1. Community Ecology

2. Ecological Niche
Ecological Niche – The role a certain species plays in an ecosystem
How does it:
Interact with other organisms
Interact with abiotic factors
What sort of things may these include?

3. Example: American Alligator

4. Alligator: Resources Resources that it uses:
Opportunistic Feeders: Fish, Turtles, Smaller Gators, Small Mammals, Birds
So what?
Gators eating these animals keeps populations of dozens of other species in check

5. Alligator: Interactions
Alligators are not aggressive unless threatened
Opportunistic feeders and will attack if hungry, and within striking range
Known to attack pets, livestock, and humans

6. Alligator: Cycling of Matter
Contribute to food chain as top predator

7. Human hunting has jeopardized alligator populations
Gators hunted for meat, skin, and for sport
Killing alligators effects the ecosystem
How?

8. Competitive Exclusion Principle
AKA – Gause’s Principle
When 2 species compete for the same resources, one is more likely to be more successful
The result will be in the second species being eliminated
Basically: 2 animals cannot occupy the same niche

9. Resource Partitioning
Some animals appear to compete for the same resources, however when examined closely, they occupy slightly different niches
Examples:
Anole Lizards in the rain forest
Warblers in the same tree

10. Character Displacement
AKA – Niche Shift
Due to resource partitioning, organisms may adapt differently to their ‘micro-niches’
This would result in less competition, and eventually evolution
divergent

11. Realized vs. Fundamental Niche
Fundamental Niche – The niche an organism occupies when no competition is present
Realized Niche – The niche an organism occupies when competition is present (NO niche overlap)

12. Energy Flow All living things need energy in order to survive
Energy flows throughout the biosphere to all living things
Energy needs to be put into a living system, otherwise it cannot function
(DNW) What energy is constantly put into the biosphere?

13. Producers Autotrophs – Organisms that produce their own food
Because they make their own food, they are also called producers

14. Producers Producers are the base of all ecosystems on earth
Producers directly and indirectly produce all the food that goes into an ecosystem

15. Producers
The most well known autotrophs used solar energy and use Photosynthesis
When sunlight is not present, autotrophs use chemicals to produce food in a process called chemosynthesis

16. Consumers
Heterotrophs – Organisms that must consume other organisms to obtain energy
These are also known as consumers
(DNW) There are many different categories of heterotrophs

17. Herbivores – Organisms that obtain energy by eating only plants

18. Carnivores – Organisms that obtain energy by consuming animals

19. Omnivores
Omnivores – Organisms that obtain energy by consuming both plants and animals

20. Scavengers/Detritivores
Scavengers/Detritivores – Organisms that feed on the tissue of dead organisms

21. Decomposers
Decomposers – Organisms that break down organic matter into simple nutrients or fertilizers

22. Trophic levels
Energy moves from one organism to another when it is eaten
Each step in this transfer of energy Is known as a trophic level
Main trophic levels
Producers
Consumers
Decomposers

23. Energy Flow It is impossible to obtain all the energy in an organism
When a rabbit eats grass, it does not obtain all of the energy in the grass
When a hawk eats the rabbit, it does not obtain all the energy in the rabbit
About 10% of energy is transferred from one trophic level to the next
This is known as the 10% law

24. Food Chain
Energy flow from 1 trophic level to the next is called a food chain
A food chain is simplified
Only one organism at each level are shown

25. Food Chains Typical food chain order: Producers (Autotrophs)
Primary consumers (Eat autotrophs)
Secondary consumers (Eat primary consumers)
Tertiary consumers (Eat secondary consumers)
Decomposers (Break down anything dead)

26. Food Chain - Example

27. Food Web Animals typically eat more than just one organism
Food webs show a greater variety in the diets of organisms

29. Arrows
The arrows point in the direction that the energy is transferred
Basically, the arrows point from the prey, to the predator

32. Ecological Pyramid
Shows the relationship between consumers and producers at different trophic levels in an ecosystem
Shows the relative amounts of energy at each trophic level
Shows what levels have the most energy and highest # of organisms

33. Ecological Pyramid

35. Symbiosis
Symbiosis – a close and permanent association between different organisms
There are three main categories of symbiosis:
Commensalism
Mutualism
Parasitism

36. Commensalism – When one organism benefits, and the other is unaffected

37. Mutualism – When both organisms benefit

38. Parasitism – When one organism benefits, and the other is harmed

39. Coevolution
Animals interacting with one another over long periods of time have led to coevolution
Examples:
Secondary Compounds
Camouflage
Aposematic (Warning) Coloration
Mimicry

40. Secondary Compounds
Secondary Compounds – Toxic chemicals produced in plants that are harmful/distasteful to herbivores
Examples:
Nicotine
Poison Oak/Ivy
Mustard oil=Toxic to insects
Hotness of Peppers

41. Camouflage
Camouflage – Any color, pattern, or shape that enables an organism to blend in with its surroundings

43. Aposomatic Coloration
A conspicuous pattern of coloration that warns other animals that they should not be eaten
Poisonous
Stinging
Bad Tasting

45. Mimicry Mimicry – When two or more species resemble one another
2 types:
Mullerian Mimicry – Animals with similar defenses have similar coloration
Batesian Mimicry – When animals with no defenses resemble organisms that do have a defense mechanism

46. Mullerian Batesian