Download ENVIRONMENTAL IMPACT OVER TIME

ENVIRONMENTAL IMPACT
OVER TIME
Chapter 2 Section 3

What types of factors
can affect the survival
of a species?

Nonliving Influences
 Temperature
 Rainfall
 Pollution
 Fire
 Elevation
 Volcanic
 Flooding
eruption

Living Influences
 Predators
 Competition
for food
 Competition for
territory

Who are Charles
Darwin and Alfred
Wallace?


British biologists
Hypothesizing about
how so many living
things came to exist on
Earth

What was their
hypothesis?


Different, long-term,
environmental
influences on
populations produced
the variety of species
Changes happen from
generation to
generation

What did Darwin and
Wallace call this
process?


Evolution—the change
in the genetics of a
species over time.
Theory to explain how,
over time, factors can
act together and result
in a new species.

How does evolution
happen?


Natural Selection—
organisms that are
better adapted to an
environment survive
and reproduce at a
greater rate than
organisms that are not
Can produce new
organisms or new
species

What are other ways
that species can
change?

Mutation
 Changes
that occur to
DNA
 Favorable mutations—
new species
 Harmful mutations—
stop reproduction or
death to organism

Selective Breeding
 People
select animals
with desirable traits
for breeding
 Ex: Labradoodle

Adaptive Radiation
 Production
of several
species from one
ancestral species
 Occurs when
environment favors
more than one
variation
 Ex: Darwin’s finches

What are two reasons
for extinction?


Habitats are
destroyed
New species are
introduced that crowd
out or prey on existing
species