1. Chapter 18: Ecology

2. What is Ecology??
The study of interactions that take place between organisms and their environment.
It explains how living organisms affect each other and the world they live in.

3. Habitat & Niche Habitat is the place a plant or animal lives
Niche is an organism’s total way of life—habitat and its role in environment

4. Niches A niche is determined by a limiting factor.
Limiting factor- any biotic or abiotic factor that restricts the existence of organisms in a specific environment.

5. Limiting Factors Examples of limiting factors - Amount of water
Amount of food
Temperature
Amount of space
Availability of mates

6. The Nonliving Environment
Abiotic factors- the nonliving parts of an organism’s environment.
Examples include air currents, temperature, moisture, light, and soil.
Abiotic factors affect an organism’s life.

7. The Living Environment
Biotic factors- all the living organisms that inhabit an environment.
All organisms depend on others directly or indirectly for food, shelter, reproduction, or protection.

8. Abiotic or Biotic?
Biotic

9. Abiotic or Biotic?
Abiotic

10. Abiotic or Biotic?
Abiotic

11. Abiotic or Biotic?
Biotic

12. Levels of Organization in Ecology

13. What are the Levels?
Organism
Population
Community
Ecosystem
Biosphere

14. 1st Level of Organization
Organism: An individual living thing that is made of cells, uses energy, reproduces, responds, grows, and develops

15. 2nd Level of Organization
Population: A group of organisms, all of the same species, which interbreed and live in the same place at the same time.

16. 3rd Level of Organization
Community: All the populations of different species that live in the same place at the same time.

17. 4th Level of Organization
Ecosystem: Populations of plants and animals that interact with each other in a given area with the abiotic components of that area.

18. 5th Level of Organization
Biosphere: The portion of Earth that supports life.

19. The Biosphere
Life is found in air, on land, and in fresh and salt water.
The BIOSPHERE is the portion of Earth that supports living things.

20. Energy Transfer
Producers: autotrophs that capture energy and use it to make organic molecules
*Photosynthesis
*Chemosynthesis
Biomass: organic material that has been produced in an ecosystem

21. Energy Transfer
Consumers: heterotrophs that obtain energy by consuming organic molecules made by other organisms
*Herbivores: eat producers
*Carnivores: eat other consumers
*Omnivores: eat both producers
and consumers
*Detritivores: feed on the “garbage” of an ecosystem via oral
ingestion
-Decomposer: a detritivore that
breaks down organic material by the
release of enzymes = decomposition

22. Energy Flow
Trophic Level: indicates organism’s position in a sequence of energy transfers
*1st trophic level = producers
*2nd trophic level = herbivores
*3rd+trophic level = consumers
-Higher trophic levels contain less energy,
so they support fewer individuals

23. Energy Transfer Through Trophic Levels

24. Energy Pyramids Show :
Amount of available energy decreases for higher consumers
It takes a large number of producers to support a small number of primary consumers
It takes a large number of primary consumers to support a small number of secondary consumers

25. Food Chains and Food Webs
Food Chain: single pathway of feeding relationships among organisms in an ecosystem that results in energy transfer
Food Web: Interrelated food chains in an ecosystem
On average, only 10% of the total energy consumed in one trophic level is incorporated into organisms in the next

26. Food Web

27. Ecosystem Recycling
As energy and matter flow through an ecosystem, matter must be recycled and reused.
Substances such as water, carbon, nitrogen, and phosphorus each pass between the living and nonliving worlds through biogeochemical cycles

28. The Water Cycle
Key processes in the water cycle are evaporation, transpiration, and precipitation.
Evaporation: Movement of water from soil & bodies of water (lakes, ponds, etc.) to the air (turning into gas)
Transpiration: Loss of water through a plant’s stomata; liquid water turns to gas
Precipitation: Water released from
the atmosphere (rain, snow, sleet,
hail)

29. The Water Cycle
Transpiration and evaporation remove water from Earth’s surface
The liquid water is turned into gas as it enters the atmosphere
Precipitation adds liquid water to Earth’s surface

30. The Carbon Cycle
Photosynthesis and cellular respiration are the two main steps in the carbon cycle.
Decreased rates of photosynthesis = excess CO2 in atmosphere (inversely-related)
Increased respiration = excess CO2 in atmosphere
Burning of fossil fuels = excess
CO2 in atmosphere
Decomposition/decay = adds CO2
to soil

31. Carbon Cycle

32. Nitrogen Cycle
Nitrogen-fixing bacteria are important in the nitrogen cycle because they change nitrogen gas into a usable form of nitrogen for plants.
N2 (gas) converted by bacteria into NO3 (nitrates) to be used by
plants

33. Nitrogen Cycle

34. Phosphorus Cycle
In the phosphorus cycle, phosphorus moves from phosphate deposited in rock, to the soil, to living organisms, and finally to the ocean.
MOST IMPORTANT POINT: PHOSPHORUS IS NOT IN THE ATMOSPHERE

35. Phosphorus Cycle