Biosphere interactions

1. Biosphere interactions March 31, 2014

2. Why are different organism’s population so different? • Why do you have a large mosquito population but a small fox population? • Interactions with biotic and abiotic factors as well as interactions within populations • Ex. Mosquitos only need water to reproduce whereas foxes need much more food to survive • Mosquitos flourish when water is present but crash when it dries out, foxes tend to stay more stable

3. What are some environmental factors that affect populations? • limiting factors – food, water, space, disease. • Ex. Fruit flies only exist when food is present, limit the amount of food and the population will drop • Organisms need space to hunt and gather food, limiting the hunting area limits the amount of food they can get • Reason why bear populations are so low

4. What happens when population out grow their resources? • Populations are controlled by their carrying capacity • The largest population that an environment can support • Whenever populations are under it they grow • Whenever population are over it they shrink • Creates a s-curve on graph

6. What about interactions within communities? • 3 types of interactions: • 1. Competition – occurs between individuals within a population • Ex. Animals that run the fastest catch food, whereas slower animals can not catch as much food. • Can also occur within communities, trees in forest have to compete to reach the available sunlight

7. 2. Predator-prey – relationship between the hunter and the hunted increase in predators decreases prey decrease in prey, decreases predator Prey have adapted different methods to combat predators ex. Camouflage, mimicry, chemicals…

8. 3. Symbiosis – whenever two different organisms live in close association with each other • 3 types • Mutualism – both benefit • Commensialism – one benefits other isn’t harmed • Parasitism – one benefits at the expense of other