1. ECOLOGY

2. Ecology
The study of organisms and their interactions with the environment
The biosphere is all the land, water and air in which organisms live.
All the living parts of an environment are called biotic factors. The nonliving parts are called abiotic factors (ex: water, light, etc.)

3. Levels of Organization in the Biosphere
Population: consists of all the members of a single species that live in one area
Community: all populations that live and interact in one environment
Ecosystem: community + abiotic factors; ex: forest, desert, ocean

4. Cycles Matter is recycled within and between ecosystems
Biogeochemical cycles show how matter cycles through the biosphere
There are 4 types of cycles:
Water cycle
Carbon cycle
Nitrogen cycle
Phosphorous cycle

5. Some Terms
Habitat: type of environment in which a particular species lives
Niche: full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditions
Biodiversity: the variety of life--the different plants, animals and micro-organisms--and the ecosystems of which they are a part

6. Food Synthesis
Photosynthesis: use of light energy to make food; process used by plants, algae and some bacteria
Chemosynthesis: use of chemical energy to make food; process used by some bacteria

7. Remember
Autotrophs: use light energy to make their own food; also called producers
Heterotrophs: can’t make their own food; also called consumers

8. Types of Heterotrophs Herbivores: eat plants Carnivores: eat animals
Omnivores: eat both plants and animals
Decomposers: break down organic matter
Scavengers: eat tissues of dead animals

9. Community Interactions
Competition: organisms attempt to use an ecological resource in the same place at the same time
Symbiosis: any relationship in which 2 species live closely together
Predation: interaction in which one organism (predator) captures and feeds on another organism (prey)

10. Types of Symbiotic Relationships
Mutualism: both organisms benefit
Parasitism: one organism benefits while the other is harmed
Commensalism: one organism benefits while the other is neither harmed nor benefited

11. Food Chains
A food chain models the flow of energy through organisms in a community
The flow is in one direction
Each step in the transfer of energy and matter in an ecological community is called a trophic level
Only 10% of the energy from one level is transferred to the level above it

12. F O D C H A I N

13. Food Web
Shows how food chains are connected

14. Ecological Pyramids
Show the relationship between producers and consumers at the trophic levels in an ecosystem
There are 3 types of pyramids:
Energy Pyramid
Biomass Pyramid
Pyramid of Numbers

15. Growth Rate
Growth rate = change in the number of individuals divided by the time period
Factors that play a role in growth rate:
Birth rate
Immigration—movement of individuals into an area
Emigration—movement of individuals out of an area
Death rate

16. Exponential Growth
Occurs when individuals in a population reproduce at a constant rate
Under ideal conditions with unlimited resources, a population will grow exponentially
As resources become less available, the growth of a population slows or stops
The red bracket shows the area of the graph that represents exponential growth.

17. Carrying Capacity
The number of individuals in a population that an environment can support over a relatively long period of time
Determined by limiting factors
Limiting factors are biotic and abiotic resources in the environment that limit the size of a population
The red bracket shows the area of the graph that represents the carrying capacity.

18. Density-Dependent Limiting Factors
Factors that become limiting only when the population is large
They include:
Living space
Disease
Competition
Predation

19. Density-Independent Limiting Factors
Factors that affect all populations in the same way, regardless of their size
They include:
Weather
Seasonal cycles
Natural disasters

20. Ecological Succession
As an ecosystem changes, older inhabitants gradually die out and new organisms move in
This series of predictable changes that occurs in a community over time is called ecological succession
There are 2 types:
Primary succession
Secondary succession

21. Primary Succession Occurs where no soil exists
Ex: occurs on surfaces formed by volcanic eruptions or on bare rock exposed when glaciers melt

22. Primary Succession

23. Secondary Succession
Occurs when a disturbance of some kind changes an existing community without removing the soil
Ex: wildfires burn woodlands or field is cleared for farming and then abandoned

24. Secondary Succession

25. Biological Magnification
Buildup of a pollutant in organisms at higher trophic levels in a food chain
ppm=parts per million