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Bio 134
15.2 DNA: Evidence of Evolution
p. 423 - 430
Essential Question
Main Idea
Multiple lines of evidence support the theory of evolution
What did On the origin of specieshow natural selection might operate
demonstrate?
What also did it provide?
Evidence that evolution has occurred on our planet
What does a theory explain?
How some aspect of the natural world operates
What does the thory of evolution All organisms on Earth have descended from a common
state?
ancestor
What do fossils provide?
A record of species that lived long ago
Important source of information for determining the
ancestry of organism and patterns of evolution
Why is the fossil record important?
What is a transitional fossil?
Fossil that contains features shared by different species
What characterisits does the
Features of modern birds and dinosaurs as well.
Archeoptrix have?
Derived Trait
Newly evolved features, such as feathers, that do NOT
appear in the fossils of common ancestors
Ancestral Trait
More primitive features, such as teeth and tails, that do
appear in ancestral forms
Homologous structures
anatomically similar structures inherited from a common
ancestor
Example of homologous
Bird Wings and reptile limbs (similar shape and construction)
strucutres:
Vestigial structures
Structures that are reduced forms of functional structures
in other organisms.
Example of vestigial structures
Snake pelvis - attachment point for legs in nonfunctional
Kiwi wings - too small to be of use
Appendix - limited use in humans
Analogous structures
Structures that can be used for the same purpose and can
be sperficially similar in construction, but are NOT inherite
from a common ancestor..
Example of analogous structures
Embryo
Wings of an Eagle or Beetle
Early, pre-birth stage of an organisms development
Example of what was explained Island have more plant diversity than animal
by migration patterns
plants are more able to migrate from closest mainland as
seeds (by wind or birds)
Biogeography
Study of the distribution of plants and animals around
the world
What are the 5 topics that offer
evidence for evolution
1 Fossil Record
2 Comparative anatomy
3 Comparative embryology
4 Comparative biochemistry
5 Geographical distribution
What is an adaptation?
Trait shaped by natural selection that increases an
organism's reproductive success.
Fitness
Measure of the relative contribution an individual trait
makes to the next generation
The
BETTER
an organism is adapted to its environment, the
GREATER
its chances of survivaland reproductive success
Camoflauge
Morphological adaptations that allow them to blend in
with their environments
Mimicry
A morphological adaptation where one species evolves
to resemble another species
When a species of bacteria is resistant to a particular
antibiotic
What is antimicrobrial resistance?
What do many scientists think is A consequence of the evolution of big brains and upright
the reason for helplessness of
human babies?
posture