1. Ecology

2. Question of the Day
Create a brief sketch including you and your community (randolph, your home(s), where you are during a normal week).
Then explain why you think it is important to know about populations.
Create a T chart for things in your environment that are alive versus things that are not alive.

3. Ecology Ecology Interaction among organisms Interactions between
organisms and their environment

4. Populations Population
The number of individuals of a species in a specific habitat
Lagos, Nigeria

5. Factors that change population size
Birth: leads to an increase
Death: leads to a decrease
Needs to be balanced for population size to remain constant
Immigration: leads to an increase
Coming into a habitat
Emmigration: leads to a decrease
Leaving a habitat

6. Changes in Pop. Size and Biodiversity
Speciation and Extinction are influenced by:
Natural causes (mutations, evolution)
Changes in climate (adaptations needed)
Human activity (deforestation, pollution)
Introduction of invasive species
Non-native species that move into a habitat and has devastating effects

7. Example of Invasive Species
Kudza Vine
Introduced from Japan for erosion control (1876) and has been growing uncontrollably ever since
Has no competitors for resources or predators
Grows (in summer) almost a foot a day

9. Australia and Its Rabbits
Rabbits were brought to Australia in for hunting and food ~ 1880s
No natural predators
Plenty of resources
Within 6 years, there hundreds of thousands
There are now about 300 million
Destroying habitats
Digs up root systems
Developing deserts

10. Rabbit Solutions Hunting Rewards Fumigation (spraying poisons)
Dynamite
Plowed
2000 mile fence
All Failed

11. Rabbit Solutions Introduced virus in 1951 (2nd invasive species)
Killed millions
But some were naturally resistant
They survived and reproduced
Bunnies are also resistant to virus (genetics)
1991, 1996: Introduced new viruses and killed many but same as above
Decision to release a new virus every two years to lessen the population (or at least keep it in check)

12. Australian Rabbits
Besides acting as an invasive species, the rabbits serve to demonstrate a second point:
Co-evolution
Two species that evolve in response to each other
Rabbits obtain immunity to virus (through genetics)
Virus evolves and begins killing again
Rabbits again obtain immunity to virus (through genetics)
This continues…

13. Food Web

14. Food Web

15. Food Webs Divided into levels known as trophic levels (feeding levels)
Composed of:
Producers
Make their own food (autotrophs)
Consumers
Must consume food (heterotroph)
Decomposers
Breaks down waste (dentritivore)

16. Producers

17. Consumers

18. Decomposers

19. Food Webs
What is your food web? Take 5 minutes to list and then map or web your food web.

20. Energy Exchange Energy is not transmitted evenly from our food
Usually only 10% of the lower trophic level makes it to the next level (most is used by the organism)

21. Complex Food Webs
Relationships between organisms are greatly intertwined
Many organisms are dependent on others for survival

22. Relationships in the Food Web
Symbiotic relationships: “living together”
Predation
Species hunt other species
Parasitism
one species benefits, one is harmed
Competition
Species “fight”/ “use” the same resources
Commensalism
one species benefit, one is unbothered
Mutualism
Both species benefit

23. Predation

24. Parasitism

25. Competition

26. Commensalism

27. Mutualism

28. Resources and Ecology Living parts of the habitat are called biotic
Any nonliving part of a habitat is known as abiotic
Rain, soil, nitrogen, carbon
Water, carbon, and nitrogen are very important for the stability of a habitat
Each is cycled through the habitat and reused

29. Nitrogen Cycle

30. Oxygen and Carbon Dioxide Cycles
Photosynthesis and cellular respiration help cycle O2 and CO2 in a habitat
Plants take in CO2 and release O2
Animals take in O2 and release CO2
Repeat, repeat, repeat

31. Carbon Cycle

32. Water Cycles

33. Biotic material is also cycled
Decomposers break down decaying organisms and add this to the soil for plant growth
Plants are then eaten by herbivores
Herbivores are eaten by carnivores
Carnivores die and decomposers consume them
The Circle of Life
Why are we the exception?