Ecology

• How is Earth a living planet?

• How do we study it?

Ecology: – Study of interconnectedness of living things.– How organisms interact and depend on each

other for survival– How they interact with and affect their

environments

What’s the Connection?

• Ex: Bee and Flower

• Ex: Squirrel and Oak tree

• Ex: Mosquitoes and Frogs

• Ex: Human driving a car and planet

Levels of Ecological Organization

• Ecologists study different levels within the environment

• Individual Organisms

• Populations

• Communities

• Ecosystems

• Biomes

• Biosphere

What might we study about…

Organisms: Looks at behavior of individuals

Only part of the story because individuals depend on each other for food, shelter and protection

Ex: – movements, – feeding behavior, – offspring produced, – sleep cycles, – migration patterns

• Ex: One white tailed deer

What might we study about…

Populations: group of individuals of same species

that live in same area and interbreed

– Ex: Herd of white tailed deer

– Look at how populations utilize resources.– How large is the population? Is it increasing,

declining? – What diseases may be affecting it– What are affects of pollution on population

• Why is it a good adaptation in many species for the juveniles to consume a different food source and live in a different part of the environment?

– Adaptation to reduce competition for resources!

What might we study about…

Communities: populations of different species

that interact and inhabit the same environment.

– A change in one population in a community will usually change and affect the other populations

• Ex: Forest Community

• How does an increase in hawk population affect the mouse population?

– What other affects would that have on other plant and animal species in the community?

What might we study about…

• Ecosystems: Communities of organisms interacting with each other and with their physical environment.

– Can involve hundreds of different species

• Terrestrial Ecosystems: on land– Ex: Forest, meadow, desert, taiga, tundra

• Aquatic Ecosystems: in fresh or salt water– Ex: Freshwater: Ponds, lakes, rivers, streams – Ex: Marine (salt): oceans

• What are some of the effects of deforestation on tropical rainforest ecosystems?

Characteristics of a Balanced Ecosystem

– Constant source of energy (ex: sunlight)

– Population of organisms that can store that energy in a usable form (autotrophic “producers”)

– Flow of energy from one population to another

– Way for materials and nutrients to be recycled

• Biomes: group of ecosystems with similar climates & typical organisms

Tropical Grassland Tropical Rain Forrest Desert

Temperate Deciduous Forest Taiga: Coniferous Forest Tundra

• Biosphere: portion of planet that supports life, (land, water, air)– A very thin layer of Earth’s total area, but it

extends high into atmosphere and deep into oceans (ex: The peel of an apple)

Living and Nonliving Environment

The physical environment and living

environment are connected in many ways

Some abiotic factors

How might they affect life here?

Biotic and Abiotic Factors

Biotic Factors: living things in an environmentthat affect other living things

– Ex: • Predators, parasites, worms in soil, decomposers recycle materials

Abiotic Factors: nonliving parts of environment thataffect living things

– Ex: • Light: intensity and duration (depends on latitude)• Temp: varies with latitude and altitude• Water: amount of precipitation

Short Clips: Biotic and Abiotic Factors:http://www.youtube.com/watch?v=woSO0D94VGA&safe=activehttp://www.youtube.com/watch?v=7Wfs2L5IydY&safe=active

Limiting Factors

• Resources that are available in the shortest supply

Ex: – Availability of food– Amount of moisture in the desert– Amount of usable nitrogen in soil

Energy Flow in Ecosystems

• All organisms need energy to power life’s processes

– Where does this energy come from?

– How is it transferred from one organism to another?

Trophic Levels

• Each step in a food chain or food web is called a trophic level.

– Primary producers are always in the first trophic level

Primary Producers

(First Trophic Level)

Autotrophs– Utilize energy from

either sunlight or chemical compounds to make their own food

– Usually at the base of a “food chain”

• Photosynthesis– Captures light energy using special pigments– Converts carbon dioxide and water into sugars

• Chemosynthesis– Harnesses chemical energy from inorganic

molecules such as hydrogen sulfide• Ex: Bacteria in deep sea volcanic vents

Capturing Energy

Consumers

(Second, Third, Forth Trophic Levels etc…)

Heterotrophs– Acquire energy and nutrients from eating other

organisms– Can’t make own food

Types of Consumers

Herbivores:

• (Primary Consumers) – eat plants

Carnivores: (Secondary Consumers) – usually kill and eat other animals (often eat

herbivores)

Scavengers: (Secondary/Tertiary Consumers)– Eats dead animals (both

herbivores and carnivores)

Omnivores: (Primary & Secondary consumers)– Eat both plants and animals

Decomposers: (Saprophytes)– Break down dead

material at all levels of food chain

Food Chains and Food Webs

Short Clip:

http://www.youtube.com/watch?v=3Bn7wdCP2v4&safe=active

• Food Chains: series of steps in which organisms transfer energy by eating and being eaten.

• Food Webs: show more complex feeding relationships and how they are interrelated– Link together all the food chains in an

ecosystem

Food Webs

Importance of Decomposers:– Eat both producers and consumers– Always the final consumer in any food chain or web– Help return nutrients from dead material back to

environment– Without them nutrients would remain locked within

dead organisms– Recyclers!

• Decomposers: http://www.youtube.com/watch?v=Z6V0a_7N1Mw&safe=active

• Rabbit decomposition:

• http://www.youtube.com/watch?v=jrSHku6-LFo&safe=active

Pyramids of Energy

• Show relative amount of energy available at each trophic level

• On average only 10% of the energy is transferred to the next level.

Most energy available at bottom

10% Rule• Part of the energy is lost as heat or is used

by organism to carry out life functions.

• Some food is not completely digested

Pyramids of Biomass

• Shows the total amount (mass) of living organic matter available at each level.

Pyramid of Numbers

• Shows relative numbers of organisms at each trophic level

How and Where Organisms Live

Niche: the role a species plays in it’s community

– How it uses and affects its environment.– What it feeds on– Where it lives– What preys on it

• Ex: – Grass = producer – Mushroom = decomposer– Centipede = predator– Worms = burrow through soil eating organic material

Habitat: where an organism lives it’s life– Ex: burrow, cave, lake, forest, soil

• Although several species may share a habitat, the food, shelter and other resources are divided into separate niches

• Distinct behaviors have developed to reduce competition for available resources

• Ex: Decaying Log has Many Niches– Animals feed in different ways on different

materials • Millipede: eats decaying leaves, • Worm: eats organic material in soil,• Centipede eats other insects

Competition: arises when niches overlap

– More than one species has same requirements

– Compete for same resources

– Organisms have evolved to be specialized and adapted to exist in their specific niche in an ecosystem

– Interspecific Competition:• between different species for same niche and

resources

– Intraspecific Competition: • between same species for same niche and

resources

• Niche Clips:• http://www.youtube.com/watch?v=6-

aGxYTUPu0&safe=active

• http://www.youtube.com/watch?v=z3eDLQym9qo&safe=active

• Food Chain Song: • http://www.youtube.com/watch?

v=TE6wqG4nb3M&safe=active

• Summary of Key Terms:• http://www.youtube.com/watch?

v=YvZlooi5_kE&safe=active

• Ecosystems and biomes:• http://www.youtube.com/watch?v=dTaWsFct32g