Evidence for Evolution Review
Hour 2 Trimester 3
Common Descent
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We have five pieces of evidence for this idea:
Homologous Structures
Fossil record
Geographic distribution of similar species
Similarities in early stage of development
Similarities in genetic sequences, DNA
The fossil record- some organisms went
through drastic change while others went
extinct or stayed relatively the same over
time.
Geographic distribution of living
species
The presence of similar but unrelated
organisms in similar environments
suggests the action of natural selection
Homologous structures
have different mature forms but develop from
the same embryonic tissues. (Some
homologous structures no longer serve
major roles in descendants. If the structures
are greatly reduced in size, they are called
vestigial organs.
Similarities in early development
The early stages, or embryos, of many
animals are very similar.
DNA Similarities
• Many sequences of DNA show common
descent of organisms. These pieces of
matching DNA code for traits found in animals
that are closely related.
Fossil Record:
The collection
of all of the
known
remains of
ancient
species
Geographic Distribution:
• Evidence for common ancestry because it
shows that organisms in similar environments
can adapt to their environments in similar
ways. Environment affects species’ traits.
Homologous Structures
• Different mature forms
(and functions) from
the same embryonic
tissues.
Co-evolution:
• is when a
species
directly
influences
the
evolution of
another
species and
both
populations
evolve in
parallel.
Cladogram:
Adaptive radiation
the pattern of adaptation that isolates a species
into two separate lineages
Flash Cards:
•Evolution
•Artificial selection
•Natural selection
•Variation
•Competition
•Fossil Record
•Embryology
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Common ancestry
Adaptive radiation
Co-evolution
Geographic
Distribution
• Homologous
Structures
• Vestigial Organs