Chapter 4-5Ecology

•Studying Ecology•Describing Populations•Energy movement through the ecosystem

Chp. 4 Vocabulary (30)• Abiotic factor

• Autotroph• Biotic factor• Carnivore• Community• Consumer• Decomposer• Detrivore• Ecology• Ecosystem

• Habitat• Herbivore• Heterotroph• Omnivore• Population• Producer• Resources• Species• Biomass• Ecological

efficiency

• Food chain• Food web• Keystone

species• Primary

consumer• Primary

producer• Primary

productivity• Pyramid of

energy• Pyramid of

numbers• Secondary

consumer• Trophic level

Levels of Ecological Levels of Ecological OrganizationOrganization• Ecology – Study of how organisms interact

with each other & with their environment• Individuals Populations

Communities Ecosystems Biosphere

• Individual species – can interbreed and produce fertile offspring

• Population – members of a species that live in the same area at the same time

• Community – all of the populations in a particular area

• Ecosystem – living & nonliving

•Biotic factors – parts of the ecosystem that are living or used to be living

•Abiotic factors – parts of the ecosystem that have never been living

Biotic & Abiotic Biotic & Abiotic FactorsFactors

•Habitat – specific environment in which an organism lives

•Organisms depend on resources provided by their habitat for survival

•Resource – anything an organism needs, incl. nutrients, shelter, mates

HabitatHabitat

•For all the levels of ecological organization (individuals to biosphere), state whether it contains only biotic factors, only abiotic factors, or both. Then, write a question that an ecologist might ask when studying life at each of the levels.

•Section 4.1 Review

Small Group

What is a population?Individuals of the

same species living in a particular area

Species can consist of many populations that are geographically isolated

Population Size• The number of individual

organisms present in a given population at a given time

• This may increase, decrease, undergo cyclical change or remain the same over time

• When size decreases quickly, it could mean extinction is coming

Passenger Pigeon•Ex. of extremes of pop.

size•Once the most abundant

bird in North America•Nested & bred in the

forests of upper Midwest and southern Canada

•Deforestation led to over hunting

•Extinct by 1914

•Characteristics of the environment that limit population growth

•Can be biotic or abiotic•Ex’s: oxygen, sunlight,

nutrients, available mates, competition, …

Limiting Factors

Ecological Communities• Life requires energy!• Organisms are classified as

either producer or consumer based on how they obtain energy

• Primary producers capture energy from the sun or other chemicals and then store it in the chemical bonds of sugars

• Autotroph = self-feeder

Photosynthesis•For almost all ecosystems,

the sun is the ultimate energy source

•Primary producers include plants, algae, cyanobacteria

•Turn light energy into chemical (bonds) energy

•CO2 & H2O is converted into C6H12O6 & O2

Chemosynthesis• Deep-sea vents host entire

communities of organisms• Complete lack of sunlight• Primary producers such as

bacteria use H2S to convert CO2 & H2O into sugars

• Chemosynthesis uses a different energy source, but like photosynthesis, it uses water & carbon dioxide to produce sugars

Small Group ActivityCO2 + H2O + energy C6H12O6 +

O2

1. List examples of autotrophs2. Describe their role in energy production3. List some factors that might influence photosynthesis4. Explain why some organisms might use chemosynthesis5. Compare/contrast photosynthesis and chemosynthesis (Venn diagram)6. What is each’s source of energy?

Consumers• Organisms that rely on other

organisms for energy and nutrients• Also called heterotrophs or “other

feeder”• Use cellular respiration to release

the energy from bonds created in photosynthesis or chemosynthesis

• Consumers & Producers use O2 with glucose to release CO2 & H2O as byproducts and make ATP energy

• Primary consumers - organisms that consume producers

• Herbivores – organisms that only consume plants

• Secondary consumers – organisms that consume the primary consumers & herbivores

• Tertiary consumers eat the secondary consumers

• Carnivores – eat only other animals

• Omnivores – eat both plant and animal food

Detritivores & Decomposers• Recyclers who help nutrients

re-enter the ecosystem• Detritivores consume detritus –

nonliving organic matter like leaf litter, waste products, dead bodies (ex. millipedes, beetles)

• Large detritivores are called scavengers (ex. vultures)

• Decomposers break down nonliving matter for reuse by primary producers (ex. fungi, bacteria)

Trophic Levels• An organism’s trophic level is its

rank in a feeding hierarchy• Primary producers always make

up the community’s 1st trophic level

• 10% Rule – each trophic level contains just 10% of the energy of the trophic level below it

• You lose 90% of the original energy in the energy used in life

Biomass• Similar to available

energy, there are generally fewer organisms at higher trophic levels than at lower ones

• Biomass is the total amount of living tissue

• For every hawk, there are more snakes, still more mice, and a huge # of plants

Energy & Biomass• Energy tranfers from one trophic

level to another within a community.• Its efficiency is only about 10%.• If 1000 units of energy are available

at the producer level of the energy pyramid, about how many units are available for primary consumers?

• For secondary consumers?• For tertiary consumers?• Why do most communities have only

about 3 or 4 trophic levels?

Food Chains & Webs• Food chain – a single linear

series of feeding relationships (what eats what now) and shows how energy moves up the trophic levels (arrows point which way?)

• Feed web – a more accurate representation of feeding relationships in a community; a visual map of all the feeding relationships and energy flow

Don’t forget the decomposers, scavengers and detritivores in the

community food web.

Florida Food Webs• How are they unique?• How are they similar to other parts of the US?

• Some species have greater influence than others

• Keystone species have a strong, wide-reaching impact on the community; its removal can alter a large portion of the food web

• Exs. – sea otters, wolves, black bear, alligator.

Keystone Species

• Section 5.3 packet• Answer the following:1.Explain the difference between a

producer & a consumer. Then explain the difference between herbivors, carnivore, omnivore, detritivore, and decomposer.

2.Write a paragraph arguing that decomposers are a “keystone group.”

Small Group Work

• Ecological succession – predictable series of changes over time that occur to a community

• Two types of succession:1.Primary succession

– No life existed2.Secondary succession

– Soil already present– Removal of biota

Community Stability

• When a disturbance is so severe, there is no vegetation or soil life

• A community is built from scratch• Takes place on bare rock, sand or

sediment that is exposed for the first time

• Pioneer species – species that colonize newly exposed land first, often have spores or seeds that can travel long distance. Ex. Lichen

• Ex. – glacier retreat, volcano, dry lake

Primary Succession

• A disturbance (fire, flood, farming, paving) alters an existing community but does not destroy all living things or organic matter

• The soil remains• Occurs faster than primary

succession• Usually grasses to shrubs to

fast growing trees to hardwoods

Secondary Succession

•Succession eventually leads to a climax community

•A stable community that completes the succession process

•Ex. Beech-maple forests in the NE US, oak, spruce

Climax Communities

• Nonnative, exotic species that spreads widely in a community

• Become invasive when limiting factors are not present in their new environment (predators, parasites, competitors)

• Not all are bad• Ex. – zebra mussels, cane toad,

kudzu, honey bees

Invasive Species