1. ECOLOGY
PART I

2. Definitions:
Ecology = branch of biology that deals with interactions between organisms and their environment and interactions among organisms
biotic factors = living factors in the environment
abiotic factors = physical factors in the environment
limiting factor = physical factor in the environment that limits population growth

3. Abiotic factors include:
light
intensity and duration varies with latitude
influences plant life and animal hibernation and migration
water has photic zone (where light penetrates)
water has aphotic zone (no light)
heterotrophs and chemotrophs

4. Abiotic factors include:
2. temperature
varies with latitude and altitude
Water
precipitation varies region to region
influenced by mountains and oceans

5. Abiotic factors include:
soil and minerals
soil layers
topsoil – organic matter, living organisms, plant liter (humus)
subsoil – rock particles, mineral and nutrients
rock from bedrock below

6. Biotic relationships:
populations
individuals of a certain species in an area
example = bullfrogs in a pond
community
different populations in a given area
example = bullfrogs, algae, fish in a pond
ecosystem
community and physical environment including biotic and abiotic factors

7. Biosphere:
portion of the earth’s surface where living things exist (about 20 km thick)
includes:
lithosphere – solid surfaces of the earth
hydrosphere – water (on, under, and vapor over)
atmosphere – air mass

8. Complete worksheet ECOSYSTEMS On page 2 in your packet

9. Nutritional Relationships

10. Autotrophic (producers)
Organisms that make their own food using CO2
Most use photosynthesis, a few use chemosynthesis
This provides food for the heterotrophs

11. Heterotrophs (Consumers) Organisms that cannot synthesize their own food
Herbivores
Carnivores
Omnivores
Saprobes

12. Herbivores
feed only on plants
rabbits, cattle, deer, sheep, horses

13. Carnivores feed on other animals (meat eaters)
Predators –attack and kill prey
(lions, hawks, wolves)
Scavengers – feed on dead animals that they find
(vultures, hyenas)

14. Omnivores
feed on plants and animals
(bears, humans)

15. Saprobes (decomposers)
organisms that obtain nutrients by breaking down remains of dead plants and animals
(fungi and mushrooms)

16. Predator population follows prey population
Predator – Prey Curve
Predator population follows prey population

17. Symbiotic Relationships
organisms that live in close association with each other and at least one benefits
Mutualism
Commensalism
Parasitism

18. Mutualism: both organisms benefit Termites and digestive organisms
Cows and digestive organisms
Lichens (algae and fungal cells)
Peas, clover, alfalfa (legumes) have nodules of bacteria on their roots that convert nitrogen gas into nitrogen in the soil that can be absorbed by the plants
The alga provides food for the fungus,
which then envelops the alga,
providing shelter and nutrients.

19. Commensalism one organism benefits and the other is not affected
Pilot fish and sharks
Barnacles on the body of a whale

20. Parasitism one organism benefits and the other is harmed
Parasite and host
Can cause slight damage – some can kill
Tape worm in animals
Mistletoe and Indian pipe in plants

21. Competition in ecosystems
Habitat – where an
organism lives
Niche – role of the species
in their ecosystem
When niches overlap –competition begins
Intraspecific (within a species)
Interspecific (between species)

22. ENERGY FLOW
Food Chains
Food Webs

23. producer consumer consumer consumer
Food Chains
producer consumer consumer consumer
(grass) (grasshopper) (frog) (hawk)

24. Food Webs
Shows all of the food chains in a community

25. Pyramid of Numbers

26. Lowest level is most numerous, most energy, most biomass
Pyramid of Numbers
TOP
3RD ORDER
2ND ORDER
1ST ORDER
HERBIVORS
GREEN PLANTS
NUTRIENTS
CARNIVORS
PRODUCERS
Lowest level is most numerous, most energy, most biomass

27. Numbers decrease going up the pyramid
Energy decreases going up the pyramid
Only about 10% of the total energy is passed level to level
Total biomass decreases going up the pyramid
Each level going up supports less numbers and less biomass
3rd level
Consumer
Secondary
Consumers
Primary
consumers
producers

28. Complete worksheet ECOSYSTEMS On pages 6 and 7 in your packet