Chapter 4-5 Ecology 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 Organization 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 & Abiotic Factors 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

Habitat 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

Small Group 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

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

Limiting Factors Characteristics of the environment that limit population growth Can be biotic or abiotic Ex’s: oxygen, sunlight, nutrients, available mates, competition, …

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 Activity CO2 + H2O + energy C6H12O6 + O2 1. List examples of autotrophs 2. Describe their role in energy production 3. List some factors that might influence photosynthesis 4. Explain why some organisms might use chemosynthesis 5. 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?

Keystone Species 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.

Small Group Work Section 5.3 packet Answer the following: Explain the difference between a producer & a consumer. Then explain the difference between herbivors, carnivore, omnivore, detritivore, and decomposer. Write a paragraph arguing that decomposers are a “keystone group.”

Community Stability Ecological succession – predictable series of changes over time that occur to a community Two types of succession: Primary succession No life existed Secondary succession Soil already present Removal of biota

Primary Succession 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

Secondary 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

Climax Communities 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

Invasive Species 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