Download 18L- Limiting Factors - Doral Academy Preparatory

Limiting Factors
Limiting factors are things that prevent a
population from ______________ any larger.
For example, 10 rabbits may live in a habitat that
has enough water, cover and space to support 20
rabbits, but if there is only enough food for ten
rabbits, the population will not grow
any_____________. In this example,
_____________ is the limiting factor.
Food is not the only factor that may limit
_____________ growth. For example, there may
be enough food to support a thousand birds in a
certain area, but only suitable nesting sites for
one hundred. Or perhaps there is plenty of food,
water, cover and space to support a larger
population of pheasants in an area, but predators
are the limiting factor.
Limiting factors are very closely tied to carrying
capacity (how many organisms can
______________ in a habitat). Many kinds of animals can
_______________ in numbers very quickly, and may temporarily
exceed the carrying capacity of their habitat. This results in stress,
starvation, disease, predation and parasites, poor reproductive
success and damage to the habitat. For example, multiplying
muskrats can very quickly _____________ all the vegetation in a
marsh. With the vegetation gone, _______________ becomes the
limiting factor and the muskrats may starve or move to
another______________. The marsh now has a reduced
_________________ _____________________ for muskrats until
the vegetation grows back again.
Common Limiting Factors are:
1. ______________
2. ______________
3. Cover and living _____________
4. ____________________ ________________ such as
earthquakes, volcanoes, tsunamis, and forest fires.
5. ___________________
6. Natural ___________________
7. _________________________ - The Black Death is estimated
to have killed 30% – 60% of
Europe's______________________, reducing the world's
population from an estimated 450 million to between 350 and
375 million in 1400. It was probably caused by the bacterium
Yersinia pestis, which was carried by Oriental rat fleas from
China living on black rats that were regular passengers on
merchant ships traveling from ______________ to the
Mediterranean and Europe.
8. Unusual __________________ conditions such as droughts,
floods, extreme temperatures.
9. _____________________
10. ________________ for plants
Niche – One way organisms reduce competition for food and
other _____________________ is to occupy a specific niche
within a habitat. A niche is the special role an organism plays
within its borders. Different species may share the
______________ habitat, but no two can have the same
________________. For example, deer, rabbits, and squirrels may
live in the same leafy ______________, but because deer browse
higher up on_____________, rabbits graze on ______________,
and squirrels ________________ acorns, each animal occupies a
different niche.
Extinction – When all the organisms of a species ___________
the species goes extinct. Most extinction occurs due to a species
not being able to adapt to _________________ in the limiting
factors and environment. Throughout Earth’s history many
instances of widespread extinction have occurred. Mass extinction
are periods when many species of organisms died out at the
_____________ time. These extinctions usually occurred when
living things could not _____________ to sudden and severe
changes in their environment. An example is the extinction of
dinosaurs 65 million years ago.