1. Ecology

2. Ecology
Ecology = the study of the interactions among organisms and their environment

3. Abiotic Factors
The nonliving or physical things in an environment are called ABIOTIC factors.
Examples:
- Sunlight
- Temperature
- Rainfall
- Air
Soil
Earthquakes

4. Biotic Factors
The living or biological things in an environment are called the biotic factors.
Examples:
parasitism
disease
predators
prey
competition

5. Levels of Organization
Ecologists study organisms ranging from the various levels of organization:
Species
Population
Community
Ecosystem
Biome
Biosphere

6. Levels of Organization
Species =a group of similar organisms that can breed and produce fertile offspring

7. Levels of Organization
Population =group of organisms, all of the same species, which interbreed and live in the same area.
EX: all the turtles in Town Lake

8. Levels of Organization
Community = a collection of different populations that live together

9. Levels of Organization
Ecosystem = a collection of interacting populations and their physical surroundings (abiotic factors)

10. Levels of Organization
Biome = a group of ecosystems with the same climate and dominant communities
Tropical rain forest
Tropical dry forest
Tropical savanna
Temperate woodland
and shrubland
Desert
Temperate grassland
Boreal forest
(Taiga)
Northwestern
coniferous forest
Temperate forest
Mountains and
ice caps
Tundra

11. Levels of Organization
Biosphere= the part of the earth where life exists including land, water, air, and atmosphere
It extends from high in the atmosphere to the bottom of the oceans.
If the earth could be shrunk to the size of an apple, the biosphere would be no thicker than the apple's skin.

12. Habitat vs. Niche HABITAT - home NICHE - job
Place where an organism lives
Lots of organisms have the same habitat
NICHE - job
Role and position a species has in its environment
Organisms want a unique niche

13. Habitat vs. Niche HABITAT NICHE
Ex: red fox’s habitat is the forests’ edge, meadows, and river bank
NICHE
Ex: red fox’s niche is a predator which feeds on the small mammals etc. that is active at night

14. Symbiotic Relationships
Symbiosis = permanent (living together) relationship between two different organisms
3 types:
Mutualism
Commensalism
Parasitism

15. Symbiotic Relationships
Mutualism = when both organisms benefit from each other
EX: clownfish and sea anemone
EX: lichen
EX: flower and bee

16. Symbiotic Relationships
2. Commensalism = one organism benefits, the other is not helped or harmed
EX: pilot fish and shark
(fish eats scraps from the shark’s food)

17. Symbiotic Relationships
3. Parasitism = one organism benefits, the other is harmed
EX: tapeworms
EX: ticks

18. Predation Relationships
Predator = an animal that feeds on another animal
Prey = that animal that is killed and eaten
EX: lion (predator) hunts and eats the zebra (prey)

19. Population Size Size of a population changes over time.
Most populations stabilize rather than grow endlessly.
Why? Because of demands on the ecosystem (ex. Enough food?)

20. Limiting Factors
Limiting Factors = any environmental factors that limit the size of a population
EX:
Availability of food
Availability of water
Availability of oxygen
Availability of sunlight

21. Density- Dependent Limiting Factors
Limit the growth of a population when the pop gets to a certain size
Population density = the # of organisms in a given area

22. Density- Dependent Limiting Factors
Two Main Factors
Competition- when a pop gets big, organisms compete for available resources
EX: group of trees fighting for sunlight, soil, or water

23. Density- Dependent Limiting Factors
2. Predation – if the predator population becomes too large, there will not be enough prey to support it

24. Density-Independent Factors
Limit the growth of a population regardless of its size
EX:
Climatic events like extreme cold/heat, tidal waves, volcanoes, flooding, drought

25. Carrying Capacity
Carrying capacity = the largest population that a given environment can support over a long period of time
Important for conservationists in managing wildlife pops

26. Competition Fundamental niche Realized niche (remember:
niche = occupation
habitat = home)

27. Key features cont. Dispersion Random, even, clumped distributions
GREAT WEBSITE:

29. QUESTIONS
Which of the following is a symbiotic relationship where both organisms benefit?
a. mutualism
b. commensalism
c. altruism
d. competition

30. Questions
2. Which of the following pairs of animals are most likely to have a predator-prey relationship?
a. dog and tapeworm
b. buffalo and tickbird
c. spider and fly
d. whale and barnacle

31. Questions
3. Some species of shark allow small fish to enter their mouths without eating them. Inside the mouth, the small fish feed on debris around the teeth. The sharks get their teeth cleaned, which reduces the risk of decay and infection. Which term best categorizes this relationship?
a. predation
b. mutualism
c. commensalism
d. parasitism

32. Questions
4. Which of the following is a density-dependent limitation on population growth?
a. wildfire
b. competition
c. unlimited nutrients
d. severe drought