Section 3: Interactions among Living Things

How Do An Organisms Adaptations Help it to Survive? ◊Natural Selection: when a trait helps an organism survive better in their environment. Those without the trait have a higher death rate. ◊Natural Selection: when a trait helps an organism survive better in their environment. Those without the trait have a higher death rate.

◊Niche: role of an organism in its habitat Type of food it eats How it gets its food What organisms it competes with How it reproduces The better suited it is to its niche the greater its chances for survival. ◊Niche: role of an organism in its habitat Type of food it eats How it gets its food What organisms it competes with How it reproduces The better suited it is to its niche the greater its chances for survival.

What are the major ways in which organism’s in an ecosystem interact? ◊Competition : Organisms competing for the same resources ◊Competition : Organisms competing for the same resources

◊Predation: predator kills prey Increase in predators--->decrease in prey Decrease in predators--->increase in prey Adaptations for predators and prey: ◊Enhanced senses ◊Camouflage ◊Warning color ◊False coloring ◊Mimicry ◊Protective covering ◊Predation: predator kills prey Increase in predators--->decrease in prey Decrease in predators--->increase in prey Adaptations for predators and prey: ◊Enhanced senses ◊Camouflage ◊Warning color ◊False coloring ◊Mimicry ◊Protective covering

Predator - Prey Interactions Year; numbers of wolves and moose ◊Reading Graphs: What variable is plotted on the x-axis? What two variables are plotted on the y- axis? ◊Reading Graphs: What variable is plotted on the x-axis? What two variables are plotted on the y- axis? Interactions Among Living Things

Predator - Prey Interactions The moose population increased and then decreased; the wolf population increased. ◊Interpreting Data: How did the moose population change between 1965 and 1972? What happened to the wolf population from 1973 through 1976? ◊Interpreting Data: How did the moose population change between 1965 and 1972? What happened to the wolf population from 1973 through 1976? Interactions Among Living Things

Predator - Prey Interactions As the moose population increased, more food was available to the wolf population and it increased. ◊Inferring: How might the change in the moose population have led to the change in the wolf population? ◊Inferring: How might the change in the moose population have led to the change in the wolf population? Interactions Among Living Things

Predator - Prey Interactions The wolf population increased. ◊Drawing Conclusions: What is one likely cause of the dip in the moose population between 1974 and 1981? ◊Drawing Conclusions: What is one likely cause of the dip in the moose population between 1974 and 1981? Interactions Among Living Things

Predator - Prey Interactions Disease would cause a decrease in the wolf population, so fewer moose would be eaten and the population could increase. ◊Predicting: How might a disease in the wolf population one year affect the moose population the next year? ◊Predicting: How might a disease in the wolf population one year affect the moose population the next year? Interactions Among Living Things

◊Symbiosis: Close relationship between 2 species ◊Symbiosis: Close relationship between 2 species

3 types of symbiotic relationships: ◊Mutualism: both species benefit ◊Ex: long eared bats and sanguaro cactus ◊Commensalism: one species benefits the other is unaffected ◊Ex: red-tailed hawk and sanguaro cactus ◊Parasitism: one species benefits while the other is harmed ◊Ex: tick and dog ◊Mutualism: both species benefit ◊Ex: long eared bats and sanguaro cactus ◊Commensalism: one species benefits the other is unaffected ◊Ex: red-tailed hawk and sanguaro cactus ◊Parasitism: one species benefits while the other is harmed ◊Ex: tick and dog

◊Mutualism: Clown fish & Sea Anemone ◊Competition: Lion & Hyena ◊Parasitism: Deer tick and human ◊Commensalism: Monarch & Milkweed ◊Predation : Lynx & Hare