Download Section 3 - mrs

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.
◊ 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
◊ 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
Interactions Among
Living Things
Predator - Prey Interactions
◊ Reading Graphs:
• What variable is
plotted on the x-axis?
What two variables
are plotted on the yaxis?
•Year; numbers of
wolves and moose
Interactions Among
Living Things
Predator - Prey Interactions
◊ Interpreting Data:
• How did the moose
population change between
1965 and 1972? What
happened to the wolf
population from 1973
through 1976?
•The moose population
increased and then decreased;
the wolf population increased.
Interactions Among
Living Things
Predator - Prey Interactions
◊ Inferring:
• How might the change
in the moose
population have led to
the change in the wolf
population?
•As the moose population
increased, more food was
available to the wolf
population and it increased.
Interactions Among
Living Things
Predator - Prey Interactions
◊ Drawing Conclusions:
• What is one likely cause of
the dip in the moose
population between 1974
and 1981?
•The wolf population
increased.
Interactions Among
Living Things
Predator - Prey Interactions
◊ Predicting:
• How might a disease in
the wolf population
one year affect the
moose population the
next year?
•Disease would cause a
decrease in the wolf
population, so fewer
moose would be eaten
and the population could
increase.
◊ 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: Clown fish &
Sea Anemone
◊ Competition: Lion
& Hyena
◊ Parasitism: Deer tick and
human
◊ Commensalism: Monarch &
Milkweed
◊ Predation: Lynx &
Hare