Transcript PPT_speciation.updated copy

What is a species?
What is a species?
INTERBREED
Mate together
FERTILE
Able to produce
offspring
SPECIES
A group of organisms
that can
interbreed(mate
together) and produce
fertile (able to have
children) offspring
The house mouse (mus musculus)
can mate with another house mouse
and produce fertile offspring. House
mousea isspecies
__________.
Zebras cannot breed with cats. They
species
aredifferent
_________________.
Horses can interbreed with donkeys,
but their offspring are not fertile, so
different
species
they are
_________________.
Think: same species
or different species?
2 cows can have fertile
children together
A lion and a tiger mate to
produce a liger, which cannot
have children
Horses cannot breed
with elephants
SPECIATION The process where
new species evolve
How does speciation
occur?
Speciation happens when
organisms cannot mate with
each other
Geographic isolation:
A physical barrier divides a
population so they can no longer
mate. They evolve different genes
so they no longer produce fertile
offspring.
Examples: floods, mountains
Think: is this
geographic isolation?
A population of frogs is
separated by a flood so they
can no longer mate
A population of rabbits
can mate with each
other:
A river separates a
population of horses:
Remember: species match their
environments because they adapt
through natural selection