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Life in General
• Living matter is organized into complex structures based on organic molecules. They have cells.
• Homeostasis is maintained by Living organisms. • Growth and development. • Reproduction and transmission of genetic information. Living
Organisms are capable of replicating themselves and Continuing their Genetic lines.
Life in General (cont’d)
• Acquisition and conversion of matter and energy from the external environment. Living Organisms are capable of integrating material from the external environment and making it a part of themselves. They are able to synthesize their own organic materials
• On this planet (at least) their is a requirement for water.
• Response to stimuli from the environment • Evolution.
Classification Systems
Classification Systems• classification is a method for organizing information • ARISTOTLE (384-322 BC) is often called the father of
biological taxonomy. • His scheme referred to common groups, such as birds,
fishes, whales, and bats, • he recognized the need for groups and group names in
the study of animals. • his system was based on the knowledge that he
possessed at the time.
Classification Systems (cont’d)
• John Ray (1627-1705) used differences in anatomy as the prime rule for classification, bringing out both the similarities and differences between groups--for example, fins or feathers.
• This is still the preferred method
Classification Systems (cont’d)
• Similar things are grouped together.• However, there are many reasonable ways of
defining similarity, and as a result many different classifications for the same things.
Classification Systems (cont’d)
• key property of classifications is that they can be nested within one another, creating an ever increasing leveled system.
• As a result any group within a classification can be split in still smaller groups .
• There is no limit to the depth of a layered classification.
Carl Linnaeus
• Linnaeus defined the biological classification system that we still use for plants and animals, and, with relatively minor changes, for fungi and microorganisms.
• It is a layered system that starts with a few categories at the highest level, and further subdivides them at each lower level.
• In the Linnaean system, to uniquely name a species it is necessary to supply both genus and species.
• In the case of animals, Linnaean classifications often reflect our "gut reactions" regarding whether an animal is similar or not.
Linnaeus (cont’d)
• biologists also classify organisms into different categories mostly by judging the levels of apparent similarity and difference that they can see.
• The assumption is that the greater the similarity, the closer they are related in a biological sense.
Classifying Organisms
• If an unknown organism is discovered, researchers begin their classification by looking for features that seem to have the same purpose as those found on other species.
• Next it will have to be determined whether or not the similarities are due to a separate evolutionary development or to a common ancestor.
• If there is a common ancestor then the two species are probably closely related and should be classified into the same or near biological categories.
Classifying Organisms (cont’d)
• Homologous structures are physical features, of different organisms, that have a similar appearance or function because they were inherited from a common ancestor that also had them.
• For example, the forelimb of a sloth, the wing of a crow, and your arm have the same functional types of bones as did our shared reptilian ancestor--these are homologous structures.
• The more such structures two organisms possess, the more likely it is that they have a close relationship.
Classifying Organisms (cont’d)
• Listing features that separate one species from another has the effect of making it look like the species and their distinctive features are fixed and eternal.
• We need to remember that they were brought about by evolutionary changes that operated not only at some time in the past, but which also continue to operate today and will surely give rise to new forms in the future.
• We also need to realize that most species are genetically varied
Biological Classification
• Biological classification is the grouping of organisms into categories that express their PHYLOGENY, or line of descent, based on information such as structure, development, biochemical functions, and evolutionary history of organisms.
• The purpose of such a classification is to provide a clear and practical way to organize and communicate information about organisms.
• Classification can show relationships between different ancient and modern groups, indicate the evolutionary pathways along which present-day organisms may have developed, and provide a basis for comparing experimental data about different plant and animal groups.
Biological Classification
• Organisms included in a group share a common genetic heritage in their genetic material, and they must be more closely related to each other than they are to the members of other groups of the same rank.
• However, classifications of organisms are modified as new information comes forward and as a result the phylogeny would change.
• Taxonomy is the method we use to group organisms. • The first scheme for classifying animals into logical
groupings may have been brought forward by Aristotle over 2,000 years ago.
• Since then many new systems have been proposed; none, however, has succeeded in fitting all plants, animals, and microorganisms into a single, completely satisfactory scheme.
Your Turn
• Complete Investigation 4a page 110 -111
Linnaeus
• Over 200 years ago Carolus Linnaeus established the first system for classifying species of plants and animals.
• He developed a categorical way of naming species and a formal hierarchy for establishing larger categories consisting of groups of species.
• Linnaeus labeled each species with a Latin double-name.
• The species name for the brown trout, for example, is Salmo trutta. The first word (with initial letter always capitalized) designates the genus (pl. genera).
• Every species belongs to a genus that may also include other species.
• We can see from its name that the trout belongs to the genus Salmo.
Linnaeus (cont’d)
• So does the closely related species Salmo Salar (Atlantic Salmon).. The second word (which always begins with a small letter) designates the species.
• A third word, indicating a sub-species may also be used, e.g. Salmo trutta caspius - the Caspian Sea Brown Trout.
• The principle of gathering categories into more specific groups is a fundamental aspect of Linnaean classification.
• The basic building block of classification is the species.• A genus is a group of related species. Genera are
grouped in families, families into orders, and so on.
Linnaean Nomenclature
• The standard nomenclature for species is attributed to Carolus LINNAEUS (1707-1778).
• The Linnaean method for classification of living things groups organisms together based on presumed similarities in structures.
• The assumption is that the more structural similarities the organisms in question share, the closer they must be in terms of evolutionary distance.
Linnaean Nomenclature (cont’d)
• The larger, more inclusive divisions of the Linnaean system (beyond species) are created by including together closely related groups of the immediately lower divisions.
• The result is a hierarchy of classification with the highest category consisting of all living things.
• The lowest category consists of a single species. • Each of the categories above species can have
numerous subcategories.
Linnaean Nomenclature (cont’d)
• Linnaeus arranged classification categories as a series of nested groups. His sequence from broadest to smallest category is: Kingdom, Phylum, Class, Order, Family, Genus, and Species.
• To remember this order you need only to remember the following:King (Kingdom) Philip (Phylum) Came (Class) Over (Order) For (Family) Good (Genus) Soup (Species)
Linnaean Nomenclature (cont’d)
• Related groups of organisms were determined by the many shared characteristics; especially those having to do with maintenance, feeding, and digestion.
Linnaean Nomenclature (cont’d)
• The basic unit in the Linnaean classification of living forms is the species.
• Each species is given a unique, two part Latin name; the name is always underlined or italicized in print.
• The name consists of the genus, which is a group of species more closely related to one another than to any other group, followed by the specific name, which identifies a particular species within a genus.
• The first letter of the genus is capitalized, while the specific name is in lowercase, as in Felis domesticus (House Cat) and Salmo salar (Atlantic Salmon).
• The binomial species name replaced the much longer descriptions of earlier classifications
Linnaean Nomenclature (cont’d)• Linnaeus named groups of organisms for the defining
characters that he noticed. • For example, the name Mammalia to the group of
animals that possess mammary glands and secrete milk to feed their young.
• He also recognized that monkeys are most nearly like humans, and as a logical consequence of strictly biological classification, humans would be grouped not only in the class Mammalia but in the same representative group as the monkeys and apes.
• Today, the decision of which species to group in a single genus is based on evolutionary relationships - that is, a genus should be a group of species all descended from a single ancestral species.
• Many biologists also consider overall anatomical resemblance in addition to strict evolutionary relatedness in making their classifications.
DEFINITION OF A SPECIES
• A Species is a group of populations that are capable of successfully breeding and producing fertile offspring.
• Animals of one species, in other words, cannot mate successfully with animals of another species (or if they do mate and have offspring the offspring are sterile) — and it is this fact of "reproductive isolation" that establishes them as members of a separate species
Binomial NomenclatureIn biology, binomial nomenclature is a standard convention used for naming species. As the word 'binomial' suggests, the scientific name of a species is formed by the combination of two terms: the genus name and the species name The first term (generic name) is always capitalized, while the specific name (trivial "name") is not; both are to be typeset in italics, e.g. Homo sapiens. The genus name can be abbreviated to its initial letter, but never omitted, (as H. sapiens) when repeated or when several species from the same genus are being listed or discussed in the same paper or report. In rare cases this abbreviation form has spread to more general use—for example the bacterium, Escherichia coli, is often referred to as just E. coli.
Binomial Nomenclature
• The importance of a standard method of naming living organisms becomes evident when you consider the multitude of names that are used for a single species as you move from locality to locality.
• Depending on where you live the term Green Pepper, Bell Pepper, Sweet Pepper or Mango are all used to describe the fruit Capsicum frutescens.
Binomial Nomenclature
Fish hawk
Osprey
(Pandion haliaetus)
Your Turn
• Find the proper scientific names for:
• Reindeer
• Caribou
• Labrador retriever
• Gorilla
• Human
• Chihuhua
Classification of Viruses• Are Virus's Living Things? • They are not classified as living organisms because they do not have a
cellular structure. • They do not have any of the structures that are found in living cells. • They consist of strands of DNA or RNA surrounded by a protein coat called
a capsid. • What are They? • Virus’s are little more than mobile genes that infect cells and cause them to
manufacture more viruses. • The capsid protects the genetic material and helps attach the virus to the
host cell • Classifying Viruses • First observed in 1935. • More than 160 groups have been identified. • They are classified mainly by the types of diseases they cause. • Different groups have different shapes.
• Viral Shapes - Polyhedral
• The Polio Virus responsible for Polio
• T4 Phage that infects E.coli
• Viral Shapes - Spherical• An example of the AIDS virus
• Viral Shapes - Cylindrical• The tobacco mosaic virus
Reproduction
• Viruses reproduce by using other organisms. • They attach to the host cell and inject their DNA
into the cell. • Virus DNA causes the cell’s metabolism to
replicate more virus DNA • New viruses are replicated and eventually burst
out of the cell. When the cell membrane breaks open it is often referred to as lyses.
• Once it breaks open the host cell dies.
Viral Diseases • There are a number of ways that viruses can infect cells. • Retroviruses (RNA viruses) use an enzyme (reverse transcriptase)
to cause the host cell to copy the viral RNA into DNA. • This new DNA instructs the cell to manufacture more viruses. • Another method is for the viral DNA to be incorporated into the host
DNA. • It remains attached as the host cell goes through many cell divisions
until it eventually completed its cycle. • While attached to the host cell it is called a provirus. • Many diseases such as AIDS and cold sores can remain inactive as
proviruses until they are triggered to complete their cycle. • People test positive for aids virus without having the symptoms of
the disease. • People who are susceptible to cold sores seem to have them come
and go at different times.
Using Viruses
• Useful pieces of genes can be copied by using viruses as a vector.
• The genes are combined with the virus DNA and when they infect cells multiple copies of the gene are made as the viruses replicate
• The multiplied genes can then be harvested.
Origin of Viruses
• Viruses are composed of genes so therefore they developed after cells.
• It is believed that they originated as fragments of genetic material that broke off from the parent chromosome.
• They survived as parasitic organisms on similar types of cells.
Virus Cell
Structural PartsProtein, Nucleic Acid Core
Nucleus, Cytoplasm, organelles, Membranes
Nucleic Acid Either DNA or RNA Both DNA and RNA
Reproduction Requires a Host CellBy Mitosis and Meiosis
Cellular Respiration No Yes
Cystallization Yes No
General Viral Information
Viruses: non-living or alive?
• A virus hijacks its host's cell machinery to create more virus particles completing the life cycle. It is the ultimate parasite!
• Viruses are somewhere between the living and non-living. They can reproduce and show inheritance, but are dependent upon their hosts, and in many ways can be treated like ordinary molecules (they can be crystallized!).
• Whether or not they are "alive", they are obligate parasites, and have no form which can reproduce independent of their host.
• Like most parasites they have a specific host range, sometimes specific to one species (or even limited cell types of one species) and sometimes more general.
Your Turn
• Read pgs. 122 – 126
• Page 126 Questions 1,2,3,5
6 methods that are utilized to classify
organisms.• Evidence from the Fossil Record
– Often Fossils can be found that illustrate a "Transition" from one species to another. When such Transitions are made it suggests commonalities between modern species. Archaeopteryx when it was discovered suggested a link between birds and reptiles.
• Anatomical Evidence – Organisms that are anatomically similar are likely to be related.
The presence of Homologous structures would suggest a reason to group organisms together. The more similar species are to one another the stronger the case for grouping them together.
• Embryological Similarity – As with the Anatomical Similarities the more similar the
organisms are during the embryological stage the stronger the case for grouping them together.
• Biochemical Similarity – Again the more similar the Biochemical makeup of the
Species the stronger the case for grouping them together
• DNA Evidence – Once more a comparison of the DNA can be used to
classify organisms. The closer the DNA the closer the relation and again the stronger the case for a similar grouping.
Modern Developments
• The approach Linnaeus took to classifying species and the majority of his taxonomic groupings remained the standard in biology for at least two centuries.
• Since the 1960s, however, a trend called cladism or cladistic taxonomy, has emerged and is expected to usurp Linnaean classification.
• In classifying species, cladists place a priority in achieving unity with the Darwinian principle of common descent.
• In essence this method seeks to establish common evolutionary patterns and group those that have a common "ancestry" together.
• This establishment of Phylogentic Relationships can be said to be the 6th means for classification.
Cladistics
In grouping species, cladists look for "procured similarities," meaning those aspects that species can be expected to share by possessing a common ancestor. This approach differs from that of phenetics, which does not address ancestry and associates species based on overall similarity.
• It also differs also from classification based on ad hoc "key characters." Cladists avail themselves of all the types of evidence available, including DNA sequences and hybridization studies, biochemistry, and traditional morphology.
• They often make use of computerized algorithms and mathematical formulae to identify the most likely phylogeny or "family tree" that relates the species they are considering.
• The science of classification has grown as knowledge and technology have grown. One leading to the other. We now know far more than Aristotle, Linnaeus, and other great Biologists of the past could have hoped to know. Projecting into the future our descendents will view our knowledge base as we view theirs. Good for their time but insufficient for ours!
• As presented in the text Biologists by in large have adopted a 6 Kingdom System of classification. The reasons for this can be distilled into an examination of the members of the former Kingdom Monera (under the 5 Kingdom System)
• Within that group it was realized that there are distinct differences between those that are known as the Archae Bacteria and the remaining members.
• For this reason the creation of a 6 Kingdom arrangement was made.
• This takes into account the unique differences and satisfies the deficiencies that the 5 Kingdom system held.
Bacteria Archaea Eukarya
Bacteria Archaea Protista Plantae Fungi Anamalia
Monera Protista Plantae Fungi Anamalia
Your Turn
• Read pgs. 122 - 126
• Page 127 Questions 2,3,4,5,6,7,8,9
Question 2• Living matter is organized into complex structures based on organic
molecules. They have cells. • Homeostasis is maintained by Living organisms. • Growth and development. • Reproduction and transmission of genetic information. Living
Organisms are capable of replicating themselves and CAcquisition and conversion of matter and energy from the external environment. Living Organisms are capable of integrating material from the external environment and making it a part of themselves. They are able to synthesize their own organic materials
• On this planet (at least) their is a requirement for water. • Response to stimuli from the environment • Evolution. • ontinuing their Genetic lines.
Question 3
• Though both exhibit characteristics of living organisms they do not have many other things (ie cell walls, movement, etc)in common
• Therefore, though they are classified a living they are not considered to be closely related
Questions 4
• The classification system is a hierarchial system, therefore, if two organisms are included in a lower classification then they must also be in the same higher taxa
• Ie all members of a family are in the same order, same class, same phylum and same kingdom
Question 5
• Though there are a number of different things scientists consider when classifying organisms in this instance the best indicator of relationships would be the anatomical similarities
• Horses and cows are adapted to be herbivores and a wolf is a predator
Question 6
• Anatomical evidence
• Biochemical evidence
• DNA evidence
• Phylogeny
• Embryonic Development
• Cladistics
• Fossil records
Question 7
• On closer inspection wing structure is about the only characteristic bats share with birds.
• The underlying structure of the wing, reproductive structures, evolution history, etc. show that bats are not closely related to birds
Question 8
• The phylogeny is the evolutionary history of the organism, it is believed that the closer in time that two organisms are related the more characteristics they will have in common
• the further back in time they are related, the less they will have in common
Question 9
• Though they do share one common characteristic, scientists use much more that simply one characteristic to classify organisms
• They combine observations and evidence from a variety of areas
Characteristics of the Kingdoms
Archaea
• differ from the true bacteria in many important respects, as well as from the eukaryotes. These differences include:
• The wall structure and chemistry. • The lipids that make up the membrane • The metabolism • Many members of this kingdom are extremophiles that
is they live in extreme environments, including water whose temperature exceeds that of boiling water such as hot spring geysers and sub sea vents.
• They are very diverse, both in form and function. Some are uni-cellular, while others form colonial arrangements.
Eubacteria
• The eubacteria are microscopic and relatively simple cells.
• They lack the nucleus and organelles of the more complex eukaryotes; however, like the cells of plants, most possess a cell wall.
• After the "archae," true bacteria are the oldest type of organism on Earth, and also the most abundant.
• They exist in soil, water, and as parasites of other organisms.
• Species and strains of bacteria cause many if not most non-hereditary diseases.
Protista
• The Kingdom Protista or Protoctista is one of the commonly recognized biological kingdoms. They include all the eukaryotes except for the plants, fungi, animals, and sometimes other groups which are
• treated in separate kingdoms. There are a few forms that are multicellular, for example the brown and red algae.
• Most though are single-celled organisms, and are typically only 0.01-0.5 mm in size, too small to be seen without a microscope.
• Protists are widespread throughout wet environments and the soil.
• Theyare able to survive dry periods by forming cysts; a few others are significant parasites.
• Traditionally they have been separated into: • Plant-like forms that contain chloroplasts, the
algae; • Fungus-like forms, the slime molds and water
molds; • Animal-like forms, the protozoa, generally
divided on the basis of structure These being: – Flagellates (e.g. Euglena) – Amoeboids (e.g. Amoeba) – Apicomplexa – Ciliates (e.g. Paramecium)
Fungi
• The Fungi (singular: fungus) are a large group of organisms.
• They include important decomposers and many parasites.
• Parasitic fungi infect animals, including us, other mammals, birds, and insects, with results varying from mild itching to death.
• Other parasitic fungi infect plants, causing disease such as Potato Blight.
• Many vascular plants are associated with mutualistic fungi, called mycorrhizae, which help with the absorption of nutrients and water. Some fungi are used as food, such as mushrooms and truffles; others are very poisonous and can cause death if eaten.
• Most fungi have vegetative bodies (called a thallus or soma) that is made up of single cell-thick filaments called hyphae.
• Generally they do not merge into a visible object, but instead form a microscopic network within the substrate, called the mycelium, through which food is absorbed.
• The fungi are absorptive heterotrophs. • The more conspicuous parts of fungi like
mushrooms are fruiting bodies, reproductive structures that produce spores.
Plantae
• This term is considerably more difficult to define than we might think.
• Our natural inclination is to regard plant as meaning a multicellular, eukaryotic organism that generally does not have sense organs or the ability to move and has, when complete, a root, stem, and leaves.
• We have to acknowledge thought that only one group, vascular plants, have "a root, stem, and leaves".
• Granted the more common plants that we encounter on a daily basis would be the vascular ones.
• Another, much broader (more inclusive) definition for plant is that it refers to anything that is photoautotrophic — that is, it is able to make its own food from light energy.
• This is a reasonable definition, and one that focuses on the role plants typically play in an ecosystem.
• Yet we must remember that there are photoautotrophs among the Prokaryotes, specifically photoautotrophic bacteria and cyanophytes. These are often referred to as the blue-green algae.
Animalia
• Animals are the group of organisms that make up the kingdom Animalia.
• Usually, they are multicellular and capable of both locomotion and responding to their surroundings.
• Unlike plants, animals do not photosynthesize, rather they consume their food: they are ingestive heterotrophs.
Plant Groups
• In order to begin to classify plants, consider the structure by which the plant absorbs water.
• Plants are either vascular or non-vascular. Vascular plants have tube-like structures that transport water from the roots to the stem to the leaves.
• Non-vascular plants absorb water only through their surfaces.
Non –Vascular Plants
• Non-vascular plants are plants that lack water-conducting vessels in their tissue known as tracheids.
• Tracheids are located in the xylem, along with wood vessels.
• They are the most important water-conducting vessels in seedless vascular plants and in gymnosperms.
Bryophytes• Bryophytes do not have a true vascular system and are
unable to pull water and nutrients up from the ground at any significant distance.
• Lacking this specialized system distinguishes bryophytes from ferns and flowering plants. It is for this reason that they are considered to be rather primitive plants.
• They are regarded as bridge between water plants like algae and higher land plants like trees.
• They are extremely dependent upon water for their survival and reproduction and are usually found in moist areas like steams and forest floors.
• They first evolved about 500 million years ago and were likely the earliest land plants.
• The lack of vascular tissue limits their size, generally keeping them under 12 centimeters high. Roots are absent in bryophytes, rather there are root-like structures known as rhizoids.
Bryophytes (cont’d)
• The word bryophyte refers to a group of plants that includes the mosses, liverworts, and hornworts. There are about 25,000 different species.
• Although small in size, they are one of the largest groups of land plants and can be found almost everywhere in the world.
• There are more species of bryophytes than the total number of conifer and fern species combined.
• A common example of the Bryophytes are Mosses. • Aside from lacking a vascular system, they have a
gametophyte-dominant life cycle, i.e. the plant's cells are haploid for most of its life cycle.
• Sporophytes (i.e. the diploid body) are short-lived and dependent on the gametophyte.
Bryophytes (cont’d)
• These plants do not flower and as a result never produce seeds.
• They reproduce by spore production• The process by which they produce spores is termed
alternation of generations.• Liverworts and mosses have been found in the fossil
record dating as far back as 300 million years ago - the Paleozoic era. As a result of an incomplete fossil record they are believed to have shared a common ancestry with the green algae.
• Bryophytes have very distinct characteristics that has allowed for the development of three distinct classes - the Hepaticae (liverworts), Anthocerotae (hornworts), and Musci (mosses).
Tracheophytes (Vascular Plants)
• The vascular plants have specialized transporting cells xylem (for transporting water and mineral nutrients) and phloem (for transporting sugars from leaves to the rest of the plant).
• When we think of plants we invariably picture vascular plants.
• Vascular plants tend to be larger and more complex than bryophytes, and have a life cycle where the sporophyte is more prominent than the gametophyte
Major evolutionary advances of the vascular plants.
Advance Green Algae Bryophytes Tracheophytes
Development of the root-stem-leaf vascular system
nonvascularized body (thallus) that may be variously shaped,no leaves, shoots, or roots
no vascular system,leaflike structures are present, but lack any vascular tissue
early vascular plants are naked, rootless vascularized stems,later vascular plants develop vascularized leaves, then roots
Reduction in the size of the gametophyte generation
wide range of life cycles, some gametophyte dominant, others sporophyte dominant
sporophyte generation dependant on gametophyte generation for food; gametophyte is free-living and photosynthetic
progressive reduction in size and complexity of the gametophyte generation, leading to its complete dependence on the sporophyte for food ,in angiosperms, 3 celled male gametophyte and a (usually) 8 celled female gametophyte
Development of seeds in some vascular plants
no seeds no seedsseed plants retain the female gametophyte on the sporophyte
Spores/Pollenspores for resisting environmental degradation
Spores that germinate into the gametophyte generation
Spores that germinate into the gametophyte generation or spores that have the gametophyte generation develop within themselves
Ferns
• Ferns are a very ancient family of plants: early fern fossils have been found before the beginning of the Mesozoic era, 360 million years ago.
• They were thriving two hundred million years before the flowering plants evolved.
• As we know them now, most ferns are leafy plants that grow in moist areas under forest canopy.
• They are "vascular plants" with well-developed internal vein structures that encourage the flow of water and nutrients.
• Unlike other vascular plants, where the adult plant grows from the seed, ferns reproduce from spores and an intermediate plant stage called a gametophyte.
Ferns (cont’d)
• There are two main differences between the ferms and other vascular plants.
• The first is that ferns are delicate plants that will only grow in areas which are moist.
• They prefer sheltered areas on the forest floor, near streams and other sources of permanent moisture.
• They cannot grow in hot dry areas like flowering plants and conifers.
• They do no have structures to prevent dessication - drying out.
Ferns (cont’d)
• The second is linked to the first: ferns reproduce differently from the conifers and flowering plants.
• It all has to do with moisture. Not just the moisture that allows the plant to live where it does, but the moisture that allows it to reproduce there. They have a more complicated method that depends on there being liquid water for the process to complete.
• The sperm cell (male gamete must "swim" to the egg). • As a result, they can only reproduce where there is
sufficient moisture: reproduction requires moisture.
• Higher plants have a very "tough" reproductive system: the pollen from the male flower is very resilient, and the female flower nurtures the seed until it is ready to grow.
• The seeds themselves are able, because of their structure, to wait for long periods in adverse conditions before they grow.
• So the higher vascular plants have evolved to occupy nearly every place on the land surface of the earth.
Seed Plants• The seed plants are divided into two groups too.
These groups are the gymnosperms and the angiosperms.
• Gymnosperms are plants which produce seeds in cones.
• One well-known type of gymnosperm is the conifer, which includes pine, fir and spruce trees.
• In this province the Gymnoserms are our dominant vegetation.
• Angiosperms are plants which make their seeds in flowers thus we call angiosperms flowering plants.
• Gymnosperms have seeds but no fruits or flowers. Gymnos means naked, sperm means seed: in other words gymnosperm equates to "naked seeds".
• Gymnosperms developed during the Paleozoic Era and became dominant during the early Mesozoic Era.
• There are over 700 living species that are placed into four divisions. These being:
• Conifers, • Cycads, • Ginkgos, and • Gnetales
• The largest, most widespread, and most familiar group are the conifers, Division Coniferophyta, that has about 550 species in 50 genera. T
• hey include many familiar trees such as Douglas firs, Black Spruce and White Spruce.
• The other three Divisions of gymnosperms are much smaller and rather obscure.
• Division Cycadophyta contains about 140 species of mainly tropical palm-like plants called cycads.
• Division Ginkgophyta contains but one species, an 80 million-year-old evolutionary leftover known as the maidenhair tree.
• Finally, Division Gnetophyta contains about 70 species, some with some very odd characteristics.
Cycads
Cycads retain some fern-like features, notably their leaf shape.
Cycads were much more prominent in the forests of the Mesozoic than they are today.
Presently, they are restricted to the tropics.
Ginkgos
The ginkgos were also a much more prominent group in the past than they are today. The sole survivor of this once hardy and varied group is Ginkgo biloba, the maidenhair tree. Extensively used as an ornamental plant, Ginkgo was thought extinct in the wild until it was discovered growing natively in a remote area of China. Ginkos have separate male and female plants. The males are more commonly planted since the females produce seeds that have a harsh odor. Pollination is by wind. Recently, Ginkgo has become the current herbal rave.
Conifers
The conifers remain the major group of gymnosperms. In this province and other regions of the world which possess similar climates and soil they are the dominant tree type. Their needle shaped leaves and other structures allow for survival in this type of environment.
•
Angiosperms
The angiosperms, were the last of the seed plant groups to evolve, and appeared over 140 million years ago during the later part of the of the Age of Dinosaurs. All Angiosperms produce flowers. Within the female parts of the flower angiosperms produce a diploid zygote and triploid endosperm. Fertilization is accomplished by a variety of pollinators, including wind, animals, and water. Two sperm are released into the female gametophyte: one fuses with the egg to produce the zygote, the other helps form the nutritive tissue known as endosperm.
• The angiosperms produce modified leaves that are grouped into flowers that in turn develop fruits and seeds.
• There are approximately 230,000 known species. Most have larger xylem cells known as vessels that improve the efficiency of their vascular systems.
• The classical view of flowering plant evolution suggests they developed from evergreen trees that produced large Magnolia-like flowers.
• Recent Fossil evidence though appears to contradict this notion and a debate among botanists has ensued.
• Regardless of their origin though it is agreed that the angiosperms underwent a significant adaptive radiation during the Cretaceous, and for the most part escaped the major extinctions that occurred at the end of the period
Invertebrates
Invertebrates
• The majority of animals on this planet are invertebrates
• 32 of the 34 phyla of animals are invertebrates
• Invertebrates lack a true defined backbone
Characteristics of Animals
• Symmetry - is the balanced distribution of duplicate body parts or shapes. The body plans of most multicellular organisms exhibit some form of symmetry, either radial symmetry or bilateral symmetry. A small minority exhibit no symmetry (are asymmetric).
• Body Cavity - (coelom) The cavity within the body of all animals higher than the coelenterates and certain primitive worms
• Digestion• Reproduction
Phylum Porifera
• Sponges – approx 5000 species• Aquatic organisms, usually marine• Usually irregularly shaped – asymmetrical ( no
plane of division)• Filter feeders – no true digestive system• Reproduction is asexual (budding) and sexual• Sexual fertilization is external - hermaphrodites• No true body cavity
Phylum Cnidaria
• Characterized by bodies that are radial symmetrical• Aquatic organisms – mostly marine• Bodies have a opening that has tentacles around it• Digestion occurs in the opening by secreting digestive
juices into the cavity and absorbing the nutrients• Reproduction is both sexual and asexual -
hermaphrodites• There is an opening but no body cavity• Sexual fertilization is external
The two different forms of a Cnidarian body
Phylum Platyhelminthes
• Flatworms – they have bilateral symmetry and show signs of cephalization (head)
• They have body tissues but do not have a true body cavity
• Single opening through which food enters and waste exits - digestion is extracelluar
• Asexual and sexual reproduction
• Fertilization is internal – hermaphrodites
Phylum Nematoda
• Roundworms – they have bilateral symmetry
• They have three layers of tissue and have a pseudocoelom (tube within a tube)
• Does not have a well developed digestive system
• One way – two openings• Sexual reproduction – internal fertilization• Hermaphrodites and separate sexes
Phylum Arthropoda
• Bilateral symmetry
• There is the presence of a true body cavity
• Digestion is in a tube with two openings and one direction
• Reproduction is sexual – with internal fertilization
• Separate sexes with a few hermaphrodites
• Scientists have identified over 1 million species
• Predict that there are over 10 million species
• Extremely diverse, thus, they can be found virtually anywhere
Why are arthropods so successful?
• Rigid, jointed external skeleton (exoskeleton)• Water proof protective armour• Site for muscle attachment• Protects against water loss
• Specialized nature of body segments• Head• Thorax• Abdomen
• Well developed nervous system• Coordinate body movement
• Diversity of structures and functions for obtaining nutrition
• Utilize plant and animal sources
