Goal 2 - Students will discover what determines a population size.

1. Goal 2 - Students will discover what determines a population size. What is competition?

2. Competition occurs whenever more than one individual or population tries to make use of the same resource.

3. Competition occurs whenever more than one individual or population tries to make use of the same resource. Roundtable: • Write down one resource that organisms compete over. • Pass your notes page to the next person in your table group. • Write down another resource on the paper that was passed to you. Do not repeat….think of something new! • We will do this a total of 4 times.

4. Limiting Factors: anything that restricts the number of individuals in a population….includes the (biotic) and (abiotic) features of the ecosystem.

5. Water

6. How many hamsters can or should live in this habitat? How many fish should live in this aquarium? Living Space

7. Mates

8. Nesting Sites and Shelter

9. Predator and Prey Predators are consumers that capture and eat other consumers. The prey is the organism that is captured by the predator.

10. Predator and Prey The deer is being eaten by the python. It is prey. The python has captured and is eating the deer.

11. Predator and Prey Predator Prey

12. Predator and Prey Predator Prey

13. Predator and Prey Predator Prey

14. Predator and Prey Alligator Python

15. Predator and Prey The alligator did get some revenge. Another alligator tried to eat the python This python swallowed the alligator. It is the predator. They were both prey

16. Symbiotic Relationships Symbiosis is a close ecological relationship between the individuals of two (or more) different species.

17. Three Types of Symbiosis • Mutualism "I WIN – YOU WIN" (+ +) • both species benefit • Commensalism "I WIN" (+ 0) •   one species benefits, the other is unaffected • Parasitism "I WIN – YOU LOSE" (+ -) • one species benefits, the other is harmed

18. Mutualism • Both organisms benefit from the relationship Otters and Kelp The otters help the kelp by eating the sea urchins which endanger it. The kelp provides and anchor for the otters while they sleep.

19. The Chital and the Tree-pie • The tree-pies help the chital by stripping the dead velvet from the antlers. This provides them with nourishment Therefore both species are benefiting from this symbiotic behavior.

20. Cleaner Fish and the Moray Eel • The cleaner fish eats parasites and food bits out of the inside of this moray eel. It gets a meal and is protected from predators by the fierce eel.

21. Commensalism • One species benefits while the other is unaffected The cattle egret and cows The cattle help the egret who look for grasshoppers and beetles that are raised by the cows. Now and then they sit on the back of a cow, looking for ticks and flies. This does not effect the cattle in any way.

22. Barnacles and Whales • Barnacles need a place to anchor. They must wait for food to come their way. Some barnacles hitch a ride on unsuspecting whales who deliver them to a food source. This does not effect the whale in any way.

23. Oak Gall Wasps and Oak Trees • The oak gall wasp stings the oak tree. The tree then grows a GALL which is a nest for the wasp’s babies. • When the larva hatch, they eat their way out of the gall. • Does not help or hurt the oak tree.

24. Parasitism • One species benefits while the other is harmed Mistletoe is an aerial parasite that has no roots of its own and lives off the tree that it attaches itself to. Without that tree it would die. It slowly chokes out the life of the host tree.

25. Bedbugs The Real Vampire!! • Bedbugs are small, nocturnal parasites that come out of hiding at night to feed on unsuspecting humans.  They feed exclusively on blood!  Their bites often result in an allergic reaction.

26. Tapeworms • The definitive host of the cucumber tapeworm is a dog or a cat (occasionally a human). Fleas and lice are the intermediate host. the dog or cat becomes contaminated when the eggs are passed in the feces, and the flea or louse ingests the eggs.  The dog or cat (or human) is infected when they ingest a flea or louse.  Hence the importance of controlling fleas on your pet!

27. Population Size • How do ecologists measure populations? • Why is it helpful to know the population size? • Indicates a healthy and growing population or a population in danger of disappearing

28. Population Density • the size of a population that occupies a specific area.

29. Measuring populations Trap-mark-release method: set traps, capture animal, mark/tag animal, release to the wild • Each time this is done, a sample count is taken and compared to previous counts Sample Counts: To estimate the number of animals in a 100-acre area, count the animals in one acre and multiply by 100.

30. Carrying Capacity • Definition: the largest number of individuals of one species that an ecosystem can support over time. • Think/Pair/Share: • How are limiting factors related to carrying capacity? • What would happen to populations if there were no limiting factors?

31. Exponential Growth • The larger the population grows, the faster it grows. • Occurs when there are little or no limiting factors • Reaches capacity when ecosystem has reached its carrying capacity for that population.