Download Species Change Over Time

Species Change Over Time
Sec 1.2
Evolution refers to the process
through which species change over
time.
The Change results from a change
in the genetic material.
This change can then be Passed
from one generation to the next!
Has communication changed over
time?
How so?
Why have phones changed over
time?
Early Ideas
Early 1800’s Jean Lamarck was first to
propose a model of how life evolved.
Lamarck proposed that an organism
could acquire a trait and then pass it
on to its’ offspring.
Darwin’s Observations
50 years after Lamarck, Charles
Darwin, a naturalist, spent 5 years
traveling around the world, aboard
the Beagle, studying rock
formations and collecting fossils
On the Galapagos Islands, a
group of volcanic islands,
Darwin found many differences
between plants and animals
from the mainland but also
from the various islands
Darwin observed similar looking birds
with very different beaks. These birds
are closely related finch species that
are suited to different food sources on
the island
Natural Selection
when members of a species are
better suited to their environment,
they will survive and reproduce at
a higher rate than other members
of the species
Key Principles of Natural Selection
Overproduction:
producing more offspring than the
environment could possibly
support, thus ensuring that the
strongest, best suited will live AND
reproduce offspring
Variation:
Differences in their genetics.
Mutations can occur causing a new
variation. This variation can be
passed on to the offspring.
Adaptations:
When a variation makes an individual
better able to survive than other
members of the group.
Any inherited trait that gives an
organism an advantage in its
environment
Selection:
Individuals with a particular
adaptation are more likely to
survive long enough to reproduce,
thus the trait is becoming more
popular in the next generation.
The trait has been selected for the
environment
Natural Selection
Overproduction
Producing more than can survive to ensure that the
strongest survive to adulthood and reproduction
↓
Variation
One of some organisms have it
↓
Adaptation
Those that have it use it to survive
↓
Selection
Those that survive reproduce. Others die off early.
What natural selection is NOT!!
Speciation: the evolution of a
species from an existing species
Due to
Isolation: species are
separated due to geographic
isolation, feed on different
things or reproduce at different
times of the year
neok12.com
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