1. Chapter 4-5 Ecology Studying Ecology Describing Populations
Energy movement through the ecosystem

2. 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

3. 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

4. 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

5. 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

6. 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

7. What is a population?
Individuals of the same species living in a particular area
Species can consist of many populations that are geographically isolated

8. 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

9. 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

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

11. 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

12. 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

13. 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

14. 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?

15. 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

16. 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

17. 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)

18. 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

19. 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

20. 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?

21. 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

22. Don’t forget the decomposers, scavengers and detritivores in the community food web.

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

24. 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.

25. 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.”

26. 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

27. 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

28. 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

29. 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

30. 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