Transcript Evolution and Classification Review

Evolution Review
Charles Darwin
• Father of:
– Evolution
• Evolution states: all life
as we know it came from
•A common
Ancestor
Fossil Record
• Comparing fossils from older and
younger rock layers document that
evolution has occurred.
Homologous structures
•Same physical characteristics/Bones
Analogous Structures
•Same Functions/Different Organisms
Examples:
Bird and Bat
Wings
Vestigial organs
• Organs that serve no useful function in
organisms.
• Humans: Appendix
• Whales: Pelvic Bone
Geographic Isolation:
• physical barriers
–Mountains
–Oceans
Natural Selection
• Survival of the fittest”
• Those that are better suited to their
environment (better phenotypes or
physical characteristics) survive and
reproduce successfully
Mutation
2. Mutations
• A mistake in DNA that
contributes to the
variation of a species
and is very important in
evolution.
Gene Flow
• Organism’s moving in and out
of an area to search for……..
–Hunt for food
–Living space
–Other resources
GENETIC DRIFT
• A change in the population because of
a random event, such as a catastrophe
• The smaller the population, the less
genetic variety it has.
alleles can be lost from one generation to
the next.
Based on this Cladogram, which organism
is most closely related to the Chimp?
-Mouse
Based on this Cladogram, all of the
organisms have jaws except:
-Hagfish
The Galapagos Island
• Darwin’s visit to these islands, the
differences in the animals, and his
observations that habitat can affect the
adaptations of organisms.
Behavioral Isolation
Camouflage
Allows organism to hide from predators
Artificial Selection
humans breed other animals and plants for particular traits.
Cute, but prone to genetically-based disorders.
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Inbreeding is preferential mating with relatives.
Inbreeding is a common form of non-random mating.
Inbreeding increases the frequency of homozygous genotypes
This increases the frequency of recessive genetic disorders.
The Genetic Basis of Evolution
Gene Pool
• are all of the alleles (alternate forms of genes) in
all of the individuals that make up a population.
Temporal Isolation
• These are closely related species, but the
American toad mates in the early part of
summer, while the Fowler's toad mates
later in the season.
Adaptation
• A favorable genetic change that allows an
organism to better survive.
– Ex. Venom
Embryology
• similarities in the early embryos indicated
that they descended from a common
ancestor