Ecology Unit

Ch 3, 4, and 6

Ch 3: The BiosphereEcology-the scientific study of interactions among organisms and their environment.

Biosphere- the combined portions of the planet in which life exists, includes land, water, air, or atmosphere.

Extends about 8km above the earths’ surface and 11 km below.

Levels of ComplexityTo study the relationships of living things, ecologists group them together based on their complexity.

Species- smallest group- organisms similar to one another that they can breed and produce new and fertile offspring

Population- group of individuals that belong to the same species and live in the same area

Communities- grouping of different populations that live together in a defined area

Ecosystem- collection of all the organism that live in a particulate place and all the nonliving things around them

Energy FlowAll living things need energy to grow and thrive.

Sunlight is the ultimate source of energy for all things

If you were ever to follow the path of energy flow backwards, you would find that it ultimately ends with the sun.

Producers/Autotrophs- organisms that can make their own chemical energy with help from the sun

Act as a source of chemical energy for other living things.

Plants, algae, and some bacteria fall into this category

Photosynthesis- process used by autotrophs to capture light energy and create chemical energy

Chemosynthesis- organisms use chemical energy to produce carbohydrates for their nourishment- like photosynthesis but without the light.

Energy Flow cont. Consumers/Heterotrophs-organisms that must consume products from their surroundings to obtain energy.

Herbivores- organisms that eat only plants and other vegetation

Carnivores- organisms that eat only meat

Omnivores- organisms that eat both meat and vegetation

Detritivores- organisms that eat dead matter

Decomposers- breakdown organic matter – bacteria and fungi

RelationshipsEnergy flows through an ecosystem in one direction, from the sun and inorganic matter, to autotrophs/producers, and then to various heterotrophs/consumers.

Food Chain - a series of steps in which organisms transfer energy be eating and being eaten.

A food chain may consist of many or a few organisms depending where the chain is occurring.

The energy flow in a food chain is one way- once it reaches the top it dies out

Relationships cont. Food Web- many food chains linked together-

Demonstrates how relationships between organisms make them dependent on each other for survival.

Shows that energy is never destroyed, merely transferred and used up until it can be recycled again.

Trophic Level- name for each step in a food chain or food web. Each consumer depends on the trophic level below it for energy.

Water CycleWater Cycle – water moves between the ocean, atmosphere, and land.

Evaporation- water changes from liquid to an atmospheric gas

Transpiration- water evaporates from the leaves of the plants

Carbon CycleCarbon Cycle- carbon is a key ingredient in all living tissue

Carbon is released into the atmosphere and cycled with oxygen through processes like photosynthesis and cell respiration.

Geological processes such as volcanoes and erosion of rocks also release carbon back into the atmosphere.

Nitrogen CycleNitrogen Cycle – nitrogen is one of the main ingredients in amino acids and proteins.

Nitrogen Gas makes up about 78% of the earth’s atmosphere

Nitrogen containing substances are recycled back into the atmosphere in waste from animals and dead and decaying matter.

denitrification- process releasing nitrogen from earth back into the atmosphere

Nitrogen fixation- converting nitrogen gas into ammonia

Phosphorous CyclePhosphorous Cycle- important for making DNA and RNA

Cycles through the dirt, water, plants, and living things.

Weather- day to day condition of the Earth’s atmosphere at a particular time and place

Climate- average year to year conditions of temperature and precipitation in a particular area

Carbon dioxide, methane, water vapor, and other gases trap heat energy in the Earth’s atmosphere and maintain the Earth’s temperature- Greenhouse Effect

Differences in latitude and angle that the sun is hitting the earth creates three main climate zones,

Polar Zones – cold areas near the poles of the Earth where the suns rays barely hit

Temperate Zones- sit between polar zones and the middle. More affected by climate change throughout the year as the earth rotates around the sun

Tropical Zones- near the equator, where the sun shines all year round and it is almost always warm.

Ecosystems are created and changed by many different factors

Biotic factors- living factors that have an effect on other living things

Abiotic factors- physical or nonliving factors that change an ecosystem

Niche- full range of physical and biological conditions in which an organism lives and works. It’ occupation.

Community Interactions, are relationships formed between living things that change ecosystems.

Predation- one organism captures and eats the other for nourishment

Predator- organism that executes the capture and kill

Prey- organism who is hunted and eaten

Symbiosis- a relationship where two species live closely together – there are three types

Mutualism- a kind of symbiosis where both species benefit

EXAMPLE: flowers and bees

Commensalism- a kind of symbiosis where one member of the relationship receives a benefit and the other is neutral

EXAMPLE: whales and barnacles

Parasitism – a kind of symbiosis where one organism lives on or inside of the other organism. The parasite obtains all of it’s nutrients from its host sometimes causing it’s host to become weak, sick, or even die.

EXAMPLE: fleas, ticks, tapeworms, and lice.

Chapter 6: Humans in the Biosphere

Many human activities affect and change the biosphere. Even today, our Earth is very different from a mere 50 years ago.

Hunting and Gathering

For most of human history, our ancestors relied on hunting animals and gathering plants for nourishment and survival

Today there are still some groups of people who hunt and gather food, however, they now use guns or other manufactured tools instead of primitive spears or bow and arrows.

Agriculture

o Early humans quickly learned how to grow foods, wait for them to ripen, and find many different uses for them. These uses included not just food, but medicine as well.

In the early 1800s and 1900s machinery entered the world of agriculture. 

Monoculture- large single fields are used for planting the same crop year after year.

Monoculture- large single fields are used for planting the same crop year after year.

Green Revolution- around the 1950s populations boomed and a food shortage followed. Governments and scientist tried to develop ways to grow food faster and grow more of it.

Challenges:

Insects that see these huge crops as great dinner tables destroying the food supply

Industrial GrowthNew age machinery entered the world, cities sprang up quickly followed by suburbs. Forests and meadows were cleared away to make room for development. Roads seem became a necessity as cars began to become better and more common and people started to travel.

Ecologists are concerned about the effects of human activity on both local and global processes. As industry boomed so did pollution and we are finding it hard to control.

Renewable/Nonrenewable Resources

There are two ways of classifying environmental goods and resources

Renewable – can regenerate if it is alive or can be replenished by natural processes if nonliving EXAMPLE: solar energy and flowing water

Non renewable – a resource that cannot be replensiehd or renewed in any way.

EXAMPLE: fossil fuels

Sustainable Environment

Sustainable Environment- a way of using natural resources without destroying them and still providing for human needs/

Human activities affect the quality and supply of resources such as land, water, forest, fish, and air.

Problems????

Soil Erosion- the wearing away of the surface soil by wind and water.

Causes areas that were once lush with trees and plants to become literally deserts of sand and dust, a process known as desertification.

 

HELP: contour plowing reduces erosion and leaving behind stems and roots of removed plants

More Problems…..

deforestation- the excessive cutting down and removal of tress. Also leads to soil erosion which can lead to flooding in some areas.

HELP: Forestry Management- strategies to help trees reproduce and grow – also involves replanting cut down trees.

More Problems…..overfishing – harvesting fish faster than they can reproduce greatly reducing the amount of fish in oceans

bicatch- fish that were not intended to be caught by the fisherman

-yet were caught and killed as a result- dolphins, sea turtles, sharks, etc.

HELP: aquaculture- raising of aquatic animals for human consumption

-fish farms and others hatcheries help fish populations grow for the purpose of being eaten so fish are not taken out of the oceans.

Still More Problems….pollution- harmful materials that enter the biosphere through land, air and water.

smog- a mixture of chemicals hanging in the air of gas emission. Often causes breathing problems and threatens health.

Acid rain - nitrogen and sulfur compounds are released into the air by gas emission. They combine with water droplets in the air to form nitric and sulfuric acids.

HELP: reduce gas emissions 

** Humans are also starting to pollute our freshwater supplies causing us to practice caution when we drink water, and also causing some animals to lose their homes.

6-3 BiodiversityBiodiversity- the sum total of genetically based variety of all organisms in the biosphere.

Kinds of biodiversity

Ecosystem- variety of habitats, communities, and ecological processes in the living world

Species- refers to the number of different species in the world

Scientists estimate that there are 1.5 million species that we know of and millions more that we have yet to discover or name

Genetic- the sum total of the different forms of genetic information that is carried by all living things.

Threats to Biodiversity

Human activity can reduce biodiversity itself and their habitats.

Extinction- when a species disappears from all or part of it’s natural habitat

Endangered Species- a species whose population size is quickly declining and in danger of extinction.

Habitat FragmentationOne large habitat where a species lives is broken up into smaller pieces. Remaining pieces become like smaller islands causing animals to becomes isolated form one another and unable to reproduce.

Invasive Species

Introducing new and exotic animals into an area where they are not naturally found.

Causes competition between the natural and invasive animals. One must win out while the other one dies, often the natural one dies. Also causes problems for humans.

EXAMPLE: cane toad frogs in Austrailia

Conservation

New fields of sciences and research are emerging that involve finding ways to protect and manage the environment and the species in it.

Unfortunately this costs a lot of money and takes a lot of time. Some fear that it may already be too late for some animals and their homes.

Global WarmingGlobal Warming is described as the increase in the average temperature of the biosphere.  

It is believed by many that our increased burning of fossil fuels and deforestation are adding carbon compounds to the air faster than unusual.  

This is causing a higher level of heat staying in the atmosphere and causing the Earth to be hotter than in the past.

There is evidence in the ice and in the fossil records that this has happened before; however, because of our need to travel and be a productive society we are causing it to happen faster than it has before.

Effects of Global Warming

Sea level rising causing flooding

Possible development of many new organisms and new habitats

Change in growing seasons for farmers

Possible mass extinction of animals.