1. What is Ecology?

Ecology (from Greek: οἶκος, oikos, "house"; -λογία, -logia, "study of") is just the study of the inclusive nature society dealing with interactions of organisms with other organisms and with the physical environment.

In biological taxonomy, kingdom and/or regnum is a taxonomic rank in either (historically) the highest rank, or (in the new three-domain system) the rank below domain. Each kingdom is divided into smaller groups called phyla (or in some contexts these are called "divisions").

Currently, many textbooks from the United States use a system of six kingdoms (Animalia, Plantae, Fungi, Protista, Archaea, Bacteria) while British and Australian textbooks may describe five kingdoms (Animalia, Plantae, Fungi, Protista, and Prokaryota or Monera). The classifications of taxonomy are life, domain, kingdom, phylum, class, order, family, genus, and species.

How are organism placed into their kingdoms?•Cell type, complex or simple•Their ability to make foodThe number of cells in their body

PlantsYou are probably quite familiar with the members of this kingdom as it contains all the plants that you have come to know - flowering plants, mosses, and ferns. Plants are all multicellular and consist of complex cells.

In addition plants are autotrophs, organisms that make their own food.

With over 250,000 species, the plant kingdom is the second largest kingdom. Plant species range from the tiny green mosses to giant trees.

AnimalsThe animal kingdom is the largest kingdom with over 1 million known species.

All animals consist of many complex cells. They are also heterotrophs. Members of the animal kingdom are found in the most diverse environments in the world.

ArchaebacteriaIn 1983, scientists tool samples from a spot deep in the Pacific Ocean where hot gases and molten rock boiled into the ocean form the Earth’s interior. To their surprise they discovered unicellular (one cell) organisms in the samples. These organisms are today classified in the kingdom, Archaebacteria.

Archaebacteria are found in extreme environments such as hot boiling water and thermal vents under conditions with no oxygen or highly acid environments.

Finding Archaebacteria: The hot springs of Yellowstone National Park, USA, were among the first places Archaebacteria were discovered. The biologists pictured above are immersing microscope slides in the boiling pool onto which some archaebacteria might be captured for study.

EubacteriaLike archaebacteria, eubacteria are complex and single celled. Most bacteria are in the EUBACTERIA kingdom. They are the kinds found everywhere and are the ones people are most familiar with.

Eubacteria are classified in their own kingdom because their chemical makeup is different.

Most eubacteria are helpful. Some produce vitamins and foods like yogurt. However, these eubacteria, Streptococci pictured above, can give you strep throat!

Fungi Fun Facts about Fungi

Some fungi taste great and others can kill you!

Mushrooms, mold and mildew are all examples of organisms in the kingdom fungi. Most fungi are multicellular and consists of many complex cells.

Fungi are organisms that biologists once confused with plants, however, unlike plants, fungi cannot make their own food. Most obtain their food from parts of plants that are decaying in the soil.

ProtistsSlime molds and algae are protists. Sometimes they are called the odds and ends kingdom because its members are so different from one another. Protists include all microscopic organisms that are not bacteria, not animals, not plants and not fungi.

Most protists are unicellular. You may be wondering why those protists are not classified in the Archaebacteria or Eubacteria kingdoms. It is because, unlike bacteria, protists are complex cells.

These delicate looking diatoms are classified in the protist kingdom.

5 Kingdoms and the Evolutionary Relationships

MONERA

PROTISTA

FUNGIANIMALIAPLANTAE

Classifications of Three Representative Species

  HUMAN HONEY BEE RED OAK

Kingdom Animalia Animalia Plantae

Phylum(Division)

Chordata Arthropoda Anthophyta

Class Mammalia Insecta Dicotyledones

Order Primates Hymenoptera Fagales

Family Hominidae Apidae Fagaceae

Genus Homo Apis Quercus

Species Homo sapiens Apis mellifera Quercus rubra

Organism

Organ AtomMolecule

Organelle

CellTissue

Population - Group of interacting and interbreeding organism of the same species.

Community - Different populations(groups of different species) living together interacting as competitors, predator and prey, or symbiotically.

Ecosystem - Organisms and their physical and chemical environments together in a particular area. "The smallest units that can sustain life in isolation from all but atmospheric surroundings."

Biosphere - Thin film on the surface of the Earth in which all life exists, the union of every ecosystems on earth. This is a highly ordered system, held together by the energy of the sun.

We have learned that Biology is hierarchical having at least these levels:

Hierarchy of Biology Biosphere Biome

Ecosystem Community Population  Organism 

Organ Systems Organs Tissues Cells

Organelles Molecules

You might notice above that the level of organism is highlighted, which is perfectly appropriate for this course! So, while biology has all of those levels of organization, we focus in this course mostly upon the individual organism. The big idea for today is to understand that when we look at the organisms, we also find that this single layer itself has many layers in another dimension. Rather than levels of organization, the organisms show incredible diversity that we distinguish in a process often called classification.

There are many ways that the organisms might be classified. Humans have traditionally grouped organisms into some major groupings and then subgroupings within each group. Humans love hierarchy, and so we naturally understand how to organize a complex mixture of organisms into groupings. This classification process could have placed the organisms into categories of usefulness...for example: those that provide food, those that provide fuel, those that provide clothing, those that perform work, those that provide pleasure, etc.

But of course plants and mammals can supply food, and they can provide clothing. So this kind of classification would be defective in that it would put dissimilar organisms into the same groups...and similar organisms into different groups. So classification by usefulness would be unnatural. Obviously something less practical but more natural was needed to be biologically significant.

Carolus Linnaeus (aka Carl von Linné) developed a hierarchical classification scheme that continues to be biologically useful to this day. This method compartmentalizes all of the organisms on the planet into categories based upon their characteristic features.

So their form (morphology), internal organization (anatomy), physiology (function), reproduction (sexual features and functions) are used to group similar organisms into a few major groups called kingdoms. Sorry ladies, but this was designed in a male-dominated culture, so there are no queendoms. These major groups include one for plants (named Plantae) and one for animals (named Animalia).

Kingdoms are obviously quite large and include a lot of organisms. Obviously some more classification was needed. So each kingdom was divided into some subdivisions called phyla. Each phylum was divided into classes, each class into orders, each order into families, each family into genera, each genus into species. So biological classification has layers like an onion too...it is hierarchical. The table below shows the classification names at each layer (taxon) for six specific organisms.

Domain Bacteria Archaea Eukarya Eukarya Eukarya Eukarya

Kingdom Eubacteria

Gram + Archaea

ProtistaHeterokonta

Stramenopiles Plantae Fungi Animalia

Phylum Proteobacteria Euryarchaeota Phaeophyta Anthophyta

Magnoliophyta Basidiomycota Chordata

Class γ-proteobacteria -- Phaeophyceae Dicotyledonae Hymenomycetes Mammalia

Order Enterobacteriales Halobacteriales Fucales Rosales Agaricales Primates

Family Enterobacteriace

ae Halobacteriaceae Fucaceae Rosaceae Agaricaceae Hominidae

Genus Escherichia Halobacterium Fucus Agaricus Homo

Species E. coli H. salinarum F. distichus R. multiflora A. bisporus H. sapiens

Common DH5α Halophytic archaean

Rockweed Wild Rose Mushroom Human

The rows in this table represent the layers of classification among organisms. The first column provides the name for each layer of taxonomy. The remaining columns give the taxa for each of six organisms. You might notice that in some cells of this table, there are multiple entries. In taxonomy there may be multiple names in use for the same taxon. For example, the phylum of the flowering plants is known as Anthophyta by some and Magnoliophyta by others. These two names for the same plants are called synonyms. You might notice that some taxa in a particular row of the table share similar endings (e.g. -ales for the family taxa). Again, while we might portray taxonomy as "universal" there are some taxa in use that do not conform universally.

NAMES OF ORGANISMS The lowest row in this table gives the common name of the organism in the column. Common names are, of course, not unique or universally understood and so they have little place in science. So while they are included here for illustration, in biology we tend to use only the scientific name for each species. The scientific name for a species is the combination of the Genus name and the Species epithet; it is thus a double name (a scientific binomial). You might notice that your human binomial is Homo sapiens, sometimes abbreviated H. sapiens. As a matter of common literacy for college students, you should learn your binomial and how to spell it! Remember, you needed to know your personal common name and how to spell it for first grade? Well, now we expect you to learn one more! Notice how Homo sapiens ends in the letter s; that letter must be present whether you are talking about one individual Homo sapiens or many Homo sapiens. You are expected to know and spell this correctly from now on!

The other observation you might make of scientific names is that they are Latin names often with Greek roots as well. Since these are Latin rather than English, it is proper to show them in italics in print but should be underlined in manuscript. The roots for our human binomial have meaning...Homo means self; it identifies us as the organism responsible for the taxonomy! The epithet sapiens means that we are capable of reasoning. Apparently we consider this to make us unique among the organisms...but that is somewhat controversial as you might guess. Scientific names are not made by combining a descriptive name in English with a -us suffix as is commonly observed on television cartoons. A coyote is not called Wolfus stupidus or Caninus acmeensis. The coyote's correct binomial is Canis latrans (dog barking) which makes it a member of the same genus (type of organism) as the wolf (Canis lupus--dog wolf) and the dog (Canis familiaris--dog household). In fact these three species can interbreed quite easily.

NUMBER OF ORGANISMS

A natural next question might be to quantify how big the classification task really is. How many organisms are there on Earth? This question is difficult to answer because, in spite of the many years of human observations and naming many, many organisms, we know there are many species yet undiscovered and undescribed on our planet! There is more work for your generation of scientists to do!

If we consider the commonly-described six kingdom taxonomy, reasonable estimates might be:

How Many Species? Bacteria - 10,000 Archaea - 1,000 Protista - 15,000 Plantae - 270,000 Fungi - 100,000

Animalia - 1,200,000

Another interesting question is how a biologist knows whether two organisms are different enough to be different species. In fact, this is not a trivial question. In ancient days of science, a species concept was advanced that if two organisms could successfully mate, then they were the same species. Of course for some species, sexual reproduction is unknown, so this could not be used for them. In other cases, offspring are produced but are defective. For example, if a mare horse is mated to a jack donkey they produce a mule. Because mules are usually sterile, donkeys and horses were considered to be different species. It is impractical if not impossible to do the controlled matings to carry out this kind of "test" for the millions of species listed above.

Plus it turns out that if we get away from mammals, matings between quite different species can sometimes produce not only viable offspring, but fertile ones too! If you ask a botanist to identify an oak tree on campus, there might not be a fast and direct answer. The red and black oaks mate easily but the offspring double their chromosomes spontaneously to become fertile new species! These new species can mate true to their hybrid type...but can also produce yet other "hybrid" species by mating back with the parental species. So what we see in the forest is, in fact, a hybrid swarm of strange combinations of oak species.

You can imagine the difficulty for scientists of coming up with unique names for each of the millions of species! Common names are much easier to coin, fewer are needed, they can vary from language to language, from location to location, and they are not necessarily unique. One common name for an organism is "Black-eyed Susan" but there are over 200 different species that have this common name in one place or another. So common names just do not provide the level of specificity needed for science! Official Latin binomials are unique to each species and the legitimate name is universal so that all scientists can be sure of the species used in a particular study. Having said that, however,

it is also true that as scientists study the biological literature they find that earlier binomials had been coined for a particular species. Because the earliest name has priority over later coined binomials, the binomial can be changed...and this leads to some synonyms for a species. While all scientists should change to the earliest and official binomial, sometimes the newer binomial has become so ingrained in the literature that it continues to be used. As an example of this phenomenon, I'll cite my own experience. I was working with the Morning Glory vine. When it came time to publish my work, I noticed that the plant physiologists who study this plant use a newer (deprecated) binomial, Pharbitis nil, rather than its "official" name, Ipomoea nil.

So which should I use in my paper? I decided to use the correct name in the title and most of the article, but did list the "common use" binomial as a synonym at the beginning of the manuscript. Taxonomy is a dynamic study, however! The groupings above the level of Genus are often revised as new information makes older groupings less than perfectly natural. In recent years, information from DNA or protein sequences have been used as characteristics to regroup organisms into different alliances at higher levels of taxonomy. And, as we shall see, the kingdom-level taxa have changed dramatically over the years...and will continue to change!

NUMBER OF KINGDOMS

In the early to mid-1900s biologists considered all the organisms to fall into two kingdoms...Plantae and Animalia. This first level of classification seemed easy. Organisms that could locomote (move from place to place) were animals, and those that could not move were plants. Of course this simple division was too superficial and put many sessile animals into the plant kingdom. And among the plant kingdom there were many organisms that just do not share many other attributes with plants. Obviously the plant kingdom was artificial and had to be divided into more natural groupings. So additional kingdoms were needed.

One of the earliest kingdoms to be divided out were those organisms that lacked a nucleus or organelles in their cells...the prokaryotic organisms. Kingdom Monera was the result, and it contained all the bacteria and related organisms of the prokaryotic type. So now there were three kingdoms. Among kingdom Plantae another large group with commonly-shared characteristics was distinguished. They lacked cellulose cell walls, using chitin instead. Their life history was more like animals than like flowering plants. So a fourth kingdom was separated out called Kingdom Fungi. This includes the molds, mildews, and mushrooms. They really are not plants and are, in fact, closer to animals in most of their characteristics.

Another group of organisms were really difficult to assign to any of these kingdoms. Some had characteristics leaning toward prokaryotic assignment to Monera, others had plant-like feature leaning toward Plantae, others were sort-of fungal leaning toward Fungi, and yet others were animal-like leaning toward Animalia. Making matters worse, there were organisms that had features somewhere in-between kingdoms. All of these difficult-to-classify organisms did have some features in common...they were fundamentally unicellular and aquatic. So an artificial (mixed descent) kingdom was created, Kingdom Protista, to hold them. Obviously further study of Protista has resulted in some of these species being moved to one of the other four kingdoms. Further study of this group will create newer kingdoms as well.

A bit later, further study among prokaryotic organisms discovered that Kingdom Monera was also an artificial kingdom. Some of these species have introns in their DNA, have different cell wall material, and many other features in common, but separate from the common bacteria. So Kingdom Monera was deprecated and split into two new kingdoms: Bacteria for the true bacteria and Archaea for the rest. If you have followed this discourse mathematically, we are up to six kingdoms. But we are not done! Kingdom Protista is admittedly artificial and needs a lot more study by your generation of scientists to figure out the natural relationships. Already, we have proposals to split out two more kingdoms from Protista. These two groups have bodies that are multicellular (though they behave mostly as independent single cells) in a unicellular kingdom. But they also differ in their plastid ultrastructure and biochemistry.

Kingdom Stramenopiles and will include the brown algae, chrysophytes, and diatoms. The red algae are also a unique group deserving a Kingdom perhaps called Rhodophyta. So we will soon be teaching about eight kingdoms... but there are others in the works. It has been projected that the ultimate resolution of Protista will end up in twelve or more kingdoms in total. These changes in the number of kingdoms is shown in the table below. Each row of this table represent a group of organisms. The color of the cell represents the kingdom assignment. The columns show the changes in those kingdom assignments over time, so time progresses left-to-right across this table.

Number of Kingdoms 2

3 5 6 8

Bacteria Bacteria Bacteria Bacteria Bacteria

Archaea Archaea Archaea Archaea Archaea

Archezoans Archezoans Archezoans Archezoans Archezoans

Euglenoids Euglenoids Euglenoids Euglenoids Euglenoids

Chrysophytes Chrysophytes Chrysophytes Chrysophytes Chrysophytes

Green Algae Green Algae Green Algae Green Algae Green Algae

Brown Algae Brown Algae Brown Algae Brown Algae Brown Algae

Red algae Red algae Red algae Red algae Red algae

Slime Molds Slime Molds Slime Molds Slime Molds Slime Molds

True Fungi True Fungi True Fungi True Fungi True Fungi

Bryophytes Bryophytes Bryophytes Bryophytes Bryophytes

Tracheophytes Tracheophytes Tracheophytes Tracheophytes Tracheophytes

Protozoans Protozoans Protozoans Protozoans Protozoans

Myxozoans Myxozoans Myxozoans Myxozoans Myxozoans

MulticellularAnimals

MulticellularAnimals

MulticellularAnimals

MulticellularAnimals

MulticellularAnimals

Taxonomists who tend to recognize more rather than fewer divisions are called "splitters" while those who tend to put groups together into fewer divisions are called "lumpers." It would seem that new information is supporting splitters more than the lumpers these days. But most biology textbooks certainly are written by lumpers. Authors seem to talk about six kingdoms in the taxonomy chapter, but then the book table of contents is clearly divided into two major units...plants and animals...as if there were really only two kingdoms and as if the year is 1955. This is why I am writing these pages for you here! There is no biology book in print now that takes the approaches we take here.

CLADISTICS

Why are the number of kingdoms or other levels of taxonomy so controversial? Why aren't the species groupings absolutely clear? Part of the answer to these questions lies in the simple fact that biology has so many species and that we know relatively very little about most of them. We need an army of biologists to figure out this mess of millions of species on our planet. So many of us are tied up studying just a few species, that most are almost completely unstudied. There is a lot of room for you in this field!

Another important basis for the lack of consensus and lack of clarity is that the diversity of organisms is the result of natural evolutionary processes that are not neatly or easily packaged into the boxes or onion layers of taxonomy. Because of this origin for the diversity, a new thrust in taxonomy has developed since the 1960s. This new way of thinking about taxonomic relationships has focused upon the evolutionary pathways by which species evolved and by which they are naturally related to each other. One could think of this as the study of phylogeny.

In evolution, species diverge to form a branching tree-like organization as time progresses, and so this new taxonomy is about branching patterns in evolution through time. It is called cladistic phylogeny or simply cladistics. Rather than thinking about kingdoms, phyla, classes, orders, families, genera, and species as nested containers for organisms, we think of how they are related to each other by virtue of the characteristics they share, and how they branched about by virtue of the characteristics they do not share.

A population is defined as all the organism within an area belonging to the same species. At this ecological level, ecologists are interested in the growth and regulation of population size, as well as the factors behind them.

1. Uniform Distribution – happens if there is auto competition for resources such as food, water, and species.

2. Random Distribution – distribution that can be found in places where environmental conditions are relatively uniform.

3. Clumping – most common pattern it happens due to varying environmental conditions.

Population density is the number of individuals of a certain species per unit area or volume, and population distribution is the pattern of dispersal of them within that area. They both are indispensable variables for ecologists to analyze and discover the spreading pattern of a certain species within a certain area and time.

The density and distribution of a population changes with time, due to abiotic factors(inorganic factors) as well as biotic factors(organic factors). Abiotic factors that could have an influence on a population include temperature, rainfall, type of soil and so forth; biotic factors are those that are related to other living things

Factors that affect population size

Immigration

Natality

Population Size

Mortality

Emigration

Theoretically, there exist 2 distinct and simple growth patterns, or mathematical models for population growth. In the first one, only one reproductive chance is given to members of the population during in their entire lifespan. Once mission accomplishes, they die. Many insects and annual plants reproduce in this manner. In the other model, members experience many reproductive events throughout their lifetime. Most vertebrates, and trees have this pattern of reproduction.

A community is comprised of all the various populations interacting in a area. An example of a community is a coral reef where numerous populations of fishes, crustacea and corals exist and interact. Ecologists try to know at this level how different relationships like predation and competition are influencing the organization and evolution of a community.

Communities distinguish from each other by two characteristics: composition and diversity. The composition of a community is simply a listing of the various species in the community. The diversity digs deeper than mere composition in that it involves both species richness(the number of species) as well as evenness (the relative abundance of different species).

A habitat is an environment wherein an organism lives and reproduces, while the ecological niche is the functional role the organism plays in its community, including its habitat as well as the interactions with other organisms.

Niche includes everything(e.g. resources an organism needs to meet its energy, nutrient, and survival demands) and every aspects of the way(e.g. the environmental features it needs to hunt and to escape successfully) an organism live with the environment, since it's difficult to delve into one niche completely, most observations concentrate on certain aspects of it.

Interspecific competition occurs when members of different species try to utilize the same resource like light, space, or nutrients that is in limited supply, or when their niches overlap. If it is unlimited, no competition would have been triggered. Competition leads to several possible outcomes. One of them is the extinction of one of the competitors.

In predation, one organism, called the predator feeds on another, called the prey.

The predators now are provided with plenty of prey to feed on, so the population increases as that of prey decreases. Again, the predators' increased number overconsume the prey, as the prey population declines, so does the prey population.

A symbiotic relationship, or symbiosis is one in which members of two populations interact very closely.

Parasitism resembles predation in that an organism called a parasite derives nourishment from another called the host(just as the predator derives nourishment from its prey), though parasites also take hosts as habitats and springboards to transmit themselves to other hosts. Parasites appear in all kingdoms of life. Some of the frequently heard of parasites include viruses(e.g., HIV), bacteria(e.g., strep infection), protists(e.g., malaria), fungi(e.g., rusts and smuts), plants(e.g., mistletoe), and animals(e.g., leeches).

Commensalism is a symbiotic relationship wherein one species is benefited and the other is neither benefited or harmed. Well known instances are those in which one species provides a habitat or a means of transportation for the other.

Example of Commensalism Animalia: Barnacles attach themselves to the backs of

whales and the shells of horseshoe crabs to get a free home and ticket for transportation. Remoras are fishes that attach themselves to the bellies of sharks by means of modified dorsal fin acting as a suction cup.

Plantae: Epiphytes grow in branches of tree in order to receiver light, but not to take nourishment from the trees. Instead, their roots obtain nutrients and water from the air.

Mutualism is a symbiotic relationship in which both species benefit. In many cases, mutualistic relationships help organisms obtain food or avoid predation. As with parasitism, it's possible to find examples of mutualism in all kingdoms.

Example of Mutualism Human & Bacteria: Human cannot synthesize vitamins by

themselves, but can benefit from some bacteria residing in their intestinal tract that make vitamins. Meanwhile, bacteria are provided with food.

Termites & Protozoa: Termites rely on the protozoa in their intestinal tract to digest wood.

To sum up, symbiotic relationships do occur between species, but the three patterns we provided may be too simple to embrace all the natural forms of symbiosis. We were just skimming roughly. Many other derivative forms of symbiosis are developed, look for other materials if you are interested.

Competition – limited resources are similarly used by two or more population.

2 kinds1. Intra – species competing with the

same species.2. Inter – species competing with different

population.

Species Diversity – measured in terms of number and relative abundance of species found in a community.

Three Domains:1. Species Diversity in Ecosystem – gives

attention to the ecological.2. Species Diversity in Geographic Region3. Species Diversity in Evolutionary Period

– original pattern and extention.

Species Stability – species that have existed in a community for a long period of time. It also determined by the relatively constant number of species and population size.

1. Optimum Temperature2. Abundant supply of food

and water3. Reproductive Capability

Ecosystem – a community of organism functioning together and interacting with physical environment.

Components of Ecosystem1. Abiotic Components2. Biotic Components

Abiotic components are such physical and chemical factors of an ecosystem as light, temperature, atmosphere gases(nitrogen, oxygen, carbon dioxide are the most important), water, wind, soil. These specific abiotic factors represent the geological, geographical, hydrological and climatological features of a particular ecosystem. Separately:

Water, which is at the same time an essential element to life and a milieu

Air, which provides oxygen, nitrogen, and carbon dioxide to living species and allows the dissemination of pollen and spores

Soil, at the same time source of nutriment and physical support. The salinity, nitrogen and phosphorus content, ability to retain water, and density are all influential.

Temperature, which should not exceed certain extremes, even if tolerance to heat is significant for some species

Light, which provides energy to the ecosystem through photosynthesis

Natural disasters can also be considered abiotic. According to the intermediate disturbance hypothesis, a moderate amount of disturbance does good to increase the biodiversity.

Example of Water Requirements of Plants

As we all know, water is essential for life and all organisms depend on it to survive in especially desert areas. Plants can be classified into 3 groups according to their water requirements:

Hydrophytes: plants which grow in water, e.g. water-lilies and rushes.Mesophytes: plants with average water requirements, e.g. roses, sweetpeas.Xerophytes: plants growing in dry environments where they often experience a shortage of water, e.g. cacti and often succulents.

Adaptations of plants to survive without water include reversed stomata rhythms, sunken stomata, thick cuticles, small leaves(or the absence of leaves) and the presence of water-storage tissues.

The living organisms are the biotic components of an ecosystem. In ecosystems, living things are classified after the way they get their food.

Autotrophs produce their own organic nutrients for themselves and other members of the community; therefore, they are called the producers. There are basically two kinds of autotrophs, chemoautotrophs and photoautogrophs. Chemautotrophs are bacteria that obtain energy by oxidizing inorganic compounds such as ammonia, nitrites, and sulfides , and they use this energy to synthesize carbohydrates. Photoautotrophs are photosynthesizers such as algae and green plants that produce most of the organic nutrients for the biosphere.

Heterotrophs, as consumers that are unable to produce, are constantly looking for source of organic nutrients from elsewhere. Herbivores like giraffe are animals that graze directly on plants or algae. Carnivores as wolf feed on other animals; birds that feed on insects are carnivores, and so are hawks that feed on birds. Omnivores are animals that feed both on plants and animals, as human.

Detritivores are organisms that rely on detritus, the decomposing particles of organic matter, for food. Earthworms and some beetles, termites, and maggots are all terrestrial detritivores. Nonphotosynthetic bacteria and fungi, including mushrooms, are decomposers that carry out decomposition, the breakdown of dead organic matter, including animal waste. Decomposers perform a very valuable service by releasing inorganic substances that are taken up by plants once more.

Everything needs energy to motion, living things are no exceptions. Sun is the ultimate source of energy for every ecosystem. The energy flow of an ecosystem starts the moment photosynthesizers capture sun light and transform it into a stock of organic compound like glucose that stores heat and energy for later use, and ends until the energy is used up or released into the surroundings in metabolic processes.

Photosynthesis explains how energy from the sun is captured by green plants and used to make food. Most of this energy is used to carry on the plant's life activities. The rest of the energy is passed on as food to the next level of the food chain.

These figure shows energy flow in a simple food chain. At each level of the food chain, about 90% of the energy is lost in the form of heat. The total energy passed from one level to the next is only about one-tenth of the energy received from the previous organism. Therefore, as you move up the food chain, there is less energy available. Animals located at the top of the food chain need a lot more food to meet their energy needs. NOTE!! Each organism in the food chain is only transfering one-tenth of its energy to the next organism.

Try this fun activity with your class to help make this more clear. Think of energy as root beer. The teacher will represent the sun and four students will represent the organisms in a food chain: a plant, an insect, a sparrow and a hawk. You will need a liter of root beer, graduated cylinders, and an eyedropper.

Reviewing the above diagram, we find that: •The sun has one liter of root beer (energy) to give. •Of that, the plant gets one-tenth or 100 milliliters. •The mouse gets 10 milliliters from the plant. •The hawk gets 1 milliliter from the mouse. •When the hawk dies and is decomposed by the mushroom, the mushroom gets only one-tenth of a milliliter!

When the root beer has been distributed in the correct amount to each participating student, they can drink their share. The extra root beer that the sun does not give to the plant, is likened unto the 90% energy lost to the environment. You as the teacher to simulate this energy loss, pour the remaining root beer down the drain and listen to the moans of your students!

After doing the activity, answer these questions. 1.Which organism was most satisfied by the amount of "energy" he or she received? Which organism was least satisfied? 2. What happened to the 900 milliliters from the sun that the plant didn't absorb? 3. How much "energy" was USED by the insect? 4. What consumer in the food chain is going to have to eat the most food to meet their energy needs? 5. Why can't a food chain have an infinite number of links?

You can see that because energy is lost at each step of a food chain, it takes a lot of producers to support a few top consumers. The food pyramid below shows an example of this.

Notice that if there were a 1000 units of energy at the producers level the primary consumers would receive 100 units of energy, the secondary consumers would receive 10 units of energy, and the tertiary consumer would receive 1 unit of energy. This pyramid helps to demonstrate the loss of energy from one level of the food chain to the next.

Primary productivity is the term used to describe the amount of organic matter an ecosystem produces from solar energy within a given area during a given period of time. Related to the concept, gross primary productivity is the total amount of organic matter produced by all autotrophs in an ecosystem, including that used by themselves. It is incurred through the process of photosaynthesis that is carried out by green plants, algae, and some bacteria. Net primary productivity, on the other hand, is defined as the total amount of energy fixed per unit of time minus the amount of energy expended by the metabolic activities of the photosynthetic organisms in the community, denoting the amount of organic matter produced by autotrophs that is available for heterotrophs.

Example of Primary Productivity

In tropical forests and in marshlands, between 1500 and 3000 grams of organic material are normally produced per square meter per year. Corresponding figures for other communities are: temperate forests, 1100 to 1500 grams; dry deserts, 200 grams. For such highly productive communities as estuaries, coral reefs, and sugarcane fields, the figures may range from 10 to 25 grams per day, for comparable annual yields of 3600 to 9100 grams.

Biomass, is the net weight of all organisms living in an ecosystem, which, increases as a result of its net production. Secondary productivity is defined as the rate of biomass accumulation by heterotrophs (herbivores, carnivores and detritivores).

Food webs refer to the complicated feeding relationships that exist among organisms in natural ecosystem. The ocean food web displayed below, however, is just the grazing food web that begins with green plant, or the producer.

FOOD CHAIN(just one path of energy)

FOOD WEB(everything is connected!)

Food Chains & Food WebsDo you like to play games? If you do, you will need energy. Every time you run or jump, you are using up energy in your body. How do you get the energy to play? You get energy from the food you eat. Similarly, all living things get energy from their food so that they can move and grow. As food passes through the body, some of it is digested. This process of digestion releases energy.

A food chain shows how each living thing gets its food. Some animals eat plants and some animals eat other animals. For example, a simple food chain links the trees & shrubs, the giraffes (that eat trees & shrubs), and the lions (that eat the giraffes). Each link in this chain is food for the next link. A food chain always starts with plant life and ends with an animal.1.Plants are called producers because they are able to use light energy from the Sun to produce food (sugar) from carbon dioxide and water.2.Animals cannot make their own food so they must eat plants and/or other animals. They are called consumers. There are three groups of consumers.

a. Animals that eat ONLY PLANTS are called herbivores (or primary consumers).b. Animals that eat OTHER ANIMALS are called carnivores.

- carnivores that eat herbivores are called secondary consumers- carnivores that eat other carnivores are called tertiary consumers e.g., killer whales in an ocean food web ... phytoplankton → small fishes → seals → killer whales

3. Animals and people who eat BOTH animals and plants are called omnivores.4. Then there are decomposers (bacteria and fungi) which feed on decaying matter.

These decomposers speed up the decaying process that releases mineral salts back into the food chain for absorption by plants as nutrients.

Image Map of the Nitrogen Cycle - What happens in the soil?

Do you know why there are more herbivores than carnivores?

In a food chain, energy is passed from one link to another. When a herbivore eats, only a fraction of the energy (that it gets from the plant food) becomes new body mass; the rest of the energy is lost as waste or used up by the herbivore to carry out its life processes (e.g., movement, digestion, reproduction). Therefore, when the herbivore is eaten by a carnivore, it passes only a small amount of total energy (that it has received) to the carnivore. Of the energy transferred from the herbivore to the carnivore, some energy will be "wasted" or "used up" by the carnivore. The carnivore then has to eat many herbivores to get enough energy to grow.

Because of the large amount of energy that is lost at each link, the amount of energy that is transferred gets lesser and lesser ...

1.The further along the food chain you go, the less food (and hence energy) remains available.

1.Most food chains have no more than four or five links.

There cannot be too many links in a single food chain because the animals at the end of the chain would not get enough food (and hence energy) to stay alive.

Most animals are part of more than one food chain and eat more than one kind of food in order to meet their food and energy requirements. These interconnected food chains form a food web.

The following is a possible food web:

Note that the arrows are drawn from food source to food consumers ... in other words, you can substitute the arrows with the words "eaten by"

A change in the size of one population in a food chain will affect other populations.

This interdependence of the populations within a food chain helps to maintain the balance of plant and animal populations within a community. For example, when there are too many giraffes; there will be insufficient trees and shrubs for all of them to eat. Many giraffes will starve and die. Fewer giraffes means more time for the trees and shrubs to grow to maturity and multiply. Fewer giraffes also means less food is available for the lions to eat and some lions will starve

to death. When there are fewer lions, the giraffe population will increase.

This ocean food web displayed above shows that krill and other herbivorous plankton feed on phytoplankton, the producer, while birds and fish feed on krill, but they are in fact omnivores because they also feed on plankton; squid hunts fish for food while enjoying some plankton once in a while as well. These herbivores and omnivores all provide energy and nutrients for a number of different carnivores, such as seals and whales.

This decomposer food web is modeled upon the detritus food chains that are based on mangrove leaves which fall into shallow estuarine water of South Florida. The bacteria and fungi of decay are the decomposers, but they can be food for other detritivores. Note that detritivores are not necessarily bacteria or fungi, they can also be large scavengers such as crabs and shrimps that feed on dead organisms and also the cast-off parts of them.

There are producers and consumers in a food web. Producers are those able to synthesize food for themselves, like phytoplankton; and all the others are consumers that rely on producers directly or indirectly for a living. Among these consumers, several different levels may be recognized. Primary consumer, or herbivores, feed directly on the green plants; secondary consumers, carnivores and parasites of animals, feed in turn on the herbivores. Decomposers or detritivores break down the organic matter accumulated in the bodies of other organisms.

All these levels, if we link them one to another in a straight-line manner, according to who eats whom, we have food chains. Food chains are selected single-lane food relationships in a series among organisms from a more complicated food web, as below:

Phytoplankton ==> krill ==> fish ==> seal==> whale

Diagrams like this that tell who eats whom are called food chains. And a trophic level is all the organisms that feed at a particular level in a food chain. In the grazing food web given at the beginning of the section, going from bottom to top, the phytoplanktons are primary producers(first trophic level), the first herbivores that feed on the them, namely the krills and herbivorous planktons are primary consumers(second trophic level), and the next group of animals are secondary consumers(third trophic level).

Numbers indicated in the diagram are measures of biomass, and the widths of the colored rectangles are so drawn that the proportions are respected. A plant fixes about 1% of solar energy that falls on its green parts. The successive members of a food chain, in turn, process into their own bodies about 10% of the energy available in the organisms on which they feed.

Aside from pyramids of biomass, there are also ecological pyramids of numbers and energy, more or less in the same impressive construction that slender representations of top consumers are set upon a huge foundation of that of producers. At the top of most food webs, just imagine the number of plants that have to be grown to support all human being.

Human Beings... masters of this planet?  Are we humans beings really the masters of this planet? Do we have the authority to self-righteously assume global dominance? The following article is my view to the questions. It is certainly not definitive. It is just an expression of my own thoughts and opinions.

In my view,  we should not assume that our human kind is central to the world and the planet at large. A human economic system should ideally also take into account the well being of the entire ecosystem, which is body of Mother Earth. I will tend to regard the Mother Earth as a living consciousness with her various elements (water, air, wildlife, etc) constantly seeking to remain in harmonious equilibrium. Come to think of it, isn’t this quite like the way the body of a living being functions?

Perhaps, economy should not be about humans for humans only. We tend to see ‘less-than-holistically’ and believe that money-making has little or nothing to do with the welfare of our Mother Earth and the ecosystem. But the fact is we humans do take sustenance from the atmosphere, animal and plant kingdoms; therefore we are dependent upon other species and resources on Earth. As such, human activities should be accounted for within a equation that does not place the human species upon a pedestal (which is being treated as superior); but rather assigns the ’so-called intelligent biped’ objectively with other species and elements of this diverse planet. In my opinion, the current human activities are simply too self-absorbed within our own kind. The truth of things is that everything, ‘however insignificant it may appear to be, is in actual fact, unique. “Feeling special” and “above others” are simply beliefs concocted by the human psyche, and have relevance only in a human society.

Holistic & equitable replenishment & redistribution amongst all elements and species on Earth should be the a central theme for sustainable living, instead of the human biased “competitive” model. I feel that perhaps recycling of used materials may not be enough. Humans, being the so-called intelligent life form on Earth should actively develop sciences that deal with replenishment of plants, animal kingdoms and elements, keeping resources in equilibrium.To achieve all that, perhaps the very mindset that first sets competition in motion has to be re-evaluated. Well, this ideal is certainly easier said than done.

Global Warming And Climate Change - How It Effects You And How You Can Help     The climate of the Earth is always changing. In the past it has altered as a result of natural causes. Nowadays, however, the term climate change is generally used when referring to changes in our climate which have been identified since the early part of the 1900's. The changes we've seen over recent years and those which are predicted over the next 80 years are thought to be mainly as a result of human behavior rather than due to natural changes in the atmosphere.

The greenhouse effect is a very important factor in climate change as it relates to the gases which keep the Earth warm; the extra greenhouse gases which activity create are thought to pose the strongest threat.Scientists across the World are looking at the evidence of climate change and are also using computer models to come up with predictions for our future environment and weather.

Looking at the knock-on effects of climate changes is a huge part of the researcher work and could cause a larger, more immediate effect.As we are likely to see an increase in rainfall and as a result sea levels rise, we could be more affected by flooding in the coming years and low

lying seaside areas could be the first victims of climate change.How will the health of humans and animals be affected by global warming, malaria – a disease spread by mosquitoes - for example, has been discovered in “cooler” countries which were never previously affected by the disease, and freak invasions of locusts are causing problems in agricultural areas in recent years. Wildlife also will be affected, already certain species have been found in new cooler areas as they move closer to the poles to escape the gradually growing heat – and in the sea, as sea temperatures rise what will the effects on coral be?The list of things we need to think about which will be affected by climate change is endless.

The only way to slow global warming and climate change is for humans to stop producing so much CO2 and other gasses and stop destroying our forests, which are the only things we have to produce more much needed oxygen in the air. Changing to use alternative energy sources, such as solar power, wind power, geothermal, water power and even nuclear energy are beginning to become increasingly popular.

Also building materials that are used in homes can help us to reduce the amount of energy we use – if your house has suitable insulation, and suitably glazed windows the need to use heating may be reduced by a few months a year, there fore creating less atmosphere destroying gasses

Causes Of Global Warming   One of the most serious environmental crises facing us today is global warming. It is the gradual increase of the earth and ocean temperature as a result of the build up of certain gases which trap heat in the atmosphere causing the earth to warm up. These heat-trapping gases are also called greenhouse gases.

Although carbon dioxide is said to be the cause of more than 60% of global warming, there are other substances which cause global warming as well, including methane, chlorofluorocarbons, and nitrous oxides. Did you ever asked yourself why the earth is heating up? Some may say it is a natural phenomenon, others may claim that man made the changes. As a matter of fact, natural causes and human activities are the factors which influence global warming.

Studies claim that billion years ago, long before man exists, there is already a warming of the planet. One of the natural cycles which believed to cause the rise of temperature is the sunspots cycle. For instance, explosions of the sun’s surface produces heat which can hit the earth causing intense temperatures. Another natural factor believed to affect global climate is the earth orbit and tilt.

Any changes of the earth orbit can cause the planet to move closer or farther from the sun. Therefore it is one of the culprits for global warming. Evidence proved that plate tectonics caused poles to be isolated from warm ocean currents. Thus it can affect our climate. Furthermore, another natural factor for global warming is the release of methane gas from wetlands and arctic tundra. One example of greenhouse gas involved in global warming is methane.

Although greenhouse gases occur naturally to keep the Earth temperature stable to maintain life, human activities increase the concentration of these gases in the atmosphere. As concentration of greenhouse gases in the atmosphere increases, the atmosphere is capable of absorbing more heat. As a result, the earth tends to warm up. In this case, man is believed to be a factor for global warming. The rise of Industrial Revolution dramatically increases the concentration of Carbon dioxide and other greenhouse gases in the atmosphere at rates much faster than the earth can cycle them.Transportations, factories, electricity from coal-fired power plants produce carbon dioxide and other heat-trapping gas in the atmosphere. Cutting down trees is another significant source of greenhouse gases, because fewer trees mean less conversion of carbon dioxide to oxygen. In addition, research shows that burning wood and fossil fuels such as gas, coal, and oil contributes carbon dioxide; methane is released from livestock and coal production; and agricultural and industrial processes produces nitrous oxide.

Pollution in the Modern World Leads to Modern Problems

In this modern world as scientists produce new technology for the welfare of mankind it only results in new luxuries being produced. This attitude by people towards the environment is changing because they want more and more luxuries and they are destroying the environment for this reason.

They use instruments like fridges, air conditioners etc that release C.F.C’s in the environment which in turn deplete the Ozone layer but these gadgets not used before the 19th century, according to recent researches the depletion of ozone has increased by about 50% in the 20th century. The uncontrolled deforestation to built buildings for their own accommodation is increasing the oxygen content in the atmosphere, which is leading to global warming.

The increasing riots also increase pollution as many cars are set on fire during the riots. This increases the temperature of that place as well as the global temperature; wars are also producing much type of pollutions like air, water, land, noise and radiation. The testing of missiles produce toxic radioactive gases like Radon, Xenon, So2 ,Co etc.

The increasing use of plastic bags leads to the pollution of the land and the sea. These plastic when buried in the earth do not decompose and convert that land into bad land not suitable for agriculture; throwing these plastic bags into the sea kills the fish. The use of loud speakers at late night parties, marriages Noise come from all over the place. Noise from road traffic, jet planes, jet skies, garbage trucks, construction equipment, manufacturing processes, lawn mowers, leaf blowers, and boom boxes, to name a few, are among the audible litter that are routinely broadcasted in the air or from road traffic, jet planes, jet skies, garbage trucks, construction equipment, manufacturing processes, lawn mowers, leaf blowers, and boom boxes lead to increase

in sound pollution which have many harmful effects like disturbance in sleep, deafness etc.At the end I would like to say that if this trend of modernization continues we will ultimately change the earth into a place, which will be full of pollution and unsuitable for flora and fauna.

Clean Sources of Energy to Avoid Contributing to Global Warming

Many people wonder what they can do to help dampen the effects of the climate crisis. One method of doing so incorporates the usage of ‘clean' energy; that is, energy that does not contribute to the levels of greenhouse gas present in our atmosphere. There are several sources of clean energy, and although it may cost more, the benefit on the planet's ecosystem is well worth the extra money. Commonly known as ‘green power', the Environmental Protection Agency has formed a partnership to help encourage the usage of these alternative sources of energy.

Wind energy is one option when it comes to renewable power. Large spinning turbines harvest the movement of the air, and the energy is transferred into an electricity generator for usage in any application. While it's not available everywhere, wind energy represents one of the fastest sectors of growth when it comes to alternative power sources, and it is consequently one of the most widely used alternative sources. As a matter of fact, since the year 2000, the number of wind turbines present in the United States has more than doubled!

Solarpower is another significant source of renewable energy. Solar cells known as photovoltaic's are placed on sun-catching areas such as the roof of a house. These cells turn light energy into electricity, and enough electric panels can provide power for an entire home, leaving you independent of the energy companies altogether.

Geothermal energy represents a source of energy that is not commonly discussed. Heat from underneath the earth's surface is harvested as steam, which helps to spin a turbine much in the way of wind power. The spinning motion is sent to an electricity generator, and the power can be used in any modern application.

Low impact hydropower represents another significant source of renewable energy. Incorporating the use of a turbine, hydropower is created in streams and rivers which produce enough of a force to properly spin the turbines. Many aspects of hydropower need to be approved to ensure that the turbines do not significantly effect wildlife that may be living in the area where the energy is being harvested. Most hydropower sources do not dam a river up; they operate with the river in free-flow as to minimize the effect on the environment.