Transcript File - Mr. Shanks` Class

F.
Endangered species
Meaning of status
1. Extinct is beyond help.
2. Extirpated can only be saved by imports.
3. Endangered is in serious trouble & we must
act fast to save these species.
4. Threatened means we have more time
before they become endangered.
5. Vulnerable means we need to be
concerned in the future.
Causes of endangerment
1. Habitat destruction Once the trees are gone, everything
that lived in them is gone as well
2. Overexploitation We are running out of many species of fish.
3. Introduction of exotic species The introduced starling has
taken nest sites from many local birds.
4. Disease, pollution, etc.
The pond still exists, but now
few things can live in it.
2] FACTORS INFLUENCING THE
STATUS OF A SPECIES
a) SIZE
b) SPECIES RANGE
c) INDIVIDUAL RANGE
d) DIET
e) BIOTIC POTENTIAL
f) HUMAN INTERACTIONS
a) SIZE
Larger animals need more food and more space.
Both eat a similar diet,
BUT one eats much more
& so needs to move more
to find more food
b) SPECIES RANGE
An animal that is found in only one place is at
risk if anything happens to that place.
The species with a smaller
range is at greater risk than
one found everywhere
c) INDIVIDUAL RANGE
How far one individual roams to find food,
mate, etc.
A larger individual
range puts the
species at greater
risk
d) DIET
A carnivore is at greater risk because its food may
become rare more readily than a herbivore’s food
e) BIOTIC POTENTIAL
Birth rate, survival to reproductive age, births per
year and births per lifetime are all part of this.
Mice breed much faster than
buffalo.
f) HUMAN INTERACTIONS
Some animals do well around people and some do not.
Some are killed
from fear.
Some are killed by cars.
Some reduce their range by avoiding humans.
Some are poisoned by pollution or purposely to kill
predators.
3. Putting all the factors together
Species A:
small, large species range, small individual
range omnivore, moderate biotic potential,
many human interactions
Five partly positive & one negative factor.
Is Species A at risk?
Species A: grey squirrel
Not at all
at risk!
Species B:
medium size, large species range, medium
individual range,omnivore, very high biotic
potential, many human interactions
Five partly positive & one negative factor.
Is Species B at risk?
Species B: Atlantic cod
On the edge of extinction
Predictions are not always easy!
The grey squirrel / human interactions
involve feeding.
The Atlantic cod / human interactions
involve killing and destroying breeding
areas.
BUT, in general, the more negative
factors, the more likely the species is to
be in trouble.
600 sites on Earth designated as places where species
are most likely to go extinct in the near future [Dec, 2005]
notice, most are tropics, only two are Canadian
answer
Endangered
questions