Transcript 1) Species have great fertility. They make more offspring

He believed that species changed over time. This happened
when they changed to adapt to their habitat.
The periodically changing currents have
allowed many different species to
immigrate to the Galapagos islands.
Some, such as sea lions, fur seals, and
penguins, could swim with the help of
the currents and giant tortoises are
known to float and could have been
carried by the same currents.
The light spores of many lower
plants could have arrived in the
islands by wind along with some
vascular plants with lighter seeds.
Spiders, small insects, and tiny
land snails are frequently
transported by wind as well. Land
birds and bats, weak fliers, would
have to have been blown to the
islands, although the seabirds
would easily have flown there.
1) Species have great fertility. They make more
offspring than can grow to adulthood.
2) Populations remain roughly the same size,
with modest fluctuations.
3) Food resources are limited, but are relatively
constant most of the time.
From these three observations it may be
inferred that in such an environment there will
be a struggle for survival among individuals.
4)In sexually reproducing species, generally no
two individuals are identical. Variation is
rampant.
5) Much of this variation is heritable.
Darwin's finches (also known as
the Galápagos Finches or as
Geospizinae) are 13 or 14
separate combinatory species of
Passerine birds (related to
American Emberizidae or
Tanagers rather than European
finches) related to a group that
Charles Darwin collected on the
Galápagos Islands during the
voyage of the Beagle. Thirteen
reside on the Galápagos Islands
and one on Cocos Island.
The birds are all about the same
size (10–20 cm). The most
important differences between
species are in the size and shape
of their beaks, and the beaks are
highly adapted to different food
sources. The birds are all brownish
or black.