Transcript Evolution Test Review

Evolution Test Review
List and describe Darwin’s
4 Principles of Evolution
Natural Selection
• Darwin’s theory of evolution
• 4 observable principles
– Overproduction
– Genetic variation
– Adaptation (of a SPECIES)
– Selection (based on greater reproductive success)
Describe evolution using a complete
sentence
Describe evolution using a couple of
complete sentences
Organisms best suited to their environment will
survive and reproduce in greater numbers.
Over time, the species will begin to look more
and more like those organisms best suited
because their genes occur in a greater % in the
population.
Whenever one organism leaves more successful offspring than
another, in time its genes will dominate the population gene pool.
Eventually, the genotype leaving fewer offspring must become
extinct in a stable population.
Ultimately, natural selection operates by different
reproductive success among organisms of the
same species.
Principle of evolution?
Principle of evolution
Variation…same species, different phenotype
due to genetic variation in traits
Principle of Evolution?
Principle of Evolution
Overproduction..organisms produce more offspring than are
likely to survive. This ensures that some will survive and the
species continues into the next generation
Organism Trait: Giraffe Coat
how many variations of this trait to do you see?
number of spots, shape of spots, shape of spots vary on one animal, color of
spot, some spots multi-colored, background hair color, pattern of spots on the
animal, border of spots, spacing between each spot…..
Massive variation of one trait
What is the role of mutation in natural
selection?
What is the role of mutation in natural
selection?
Mutations are a source of
genetic variation.
Mutation is NOT a principle
of evolution.
What is speciation?
Describe the process that leads to speciation.
Speciation is due to Geographic Isolation
Eventually this leads
…reproductive isolation
This means new species
have evolved. Even if
You put these new
organisms “back together”
they will not reproduce
with each other because
they do not recognize
each other as the same
species.
Evidence of Evolution
What are the types of evidence used to
determine the evolutionary relationship
between species?
1. Comparative Anatomy
-homologous structures
-analogous structures
-vestigial structures
2. Embryological
3. Molecular (DNA)
4. Fossil
1. Comparative Anatomy
-homologous structures
divergent evolution
common ancestor
similar structure, different function
-analogous structures
convergent evolution
evolved in same environment (~ pressures)
similar function, different structure
Homologous or Analogous
Elephant Leg
Homologous or Analogous?
Butterfly and Bird wing
are Analogous structures
they have similar functions
but a very different
underlying structure.
Elephant Leg
Elephant Leg and Bird wings
are Homologous structures
the underlying bone structure is very similar
Homologous or Analogous?
Butterfly and Bird wing
are Analogous structures
they have similar functions
but a very different
underlying structure.
Elephant Leg
Elephant Leg and Bird wings
are Homologous structures
the underlying bone structure is very similar
Homologous or Analogous
Homologous
similar structure, different function
Function ---flying
Function-----grasping
function----crawling along the ground
What evidence is represented here?
This is a vestigial structure…
Is it considered a homologous or analogous structure?
This is a vestigial structure…
Is it considered a homologous or analogous structure?
Homologous..similar structure (limb), different function (none)
Which are most closely related?
Evidence that supports your answer.
Kingdom
Animal
Animal
Animal
Animal
Animal
Phylum
Chordata
Chordata
Chordata
Chordata
Chordata
Class
Aves
Aves
Aves
Aves
Aves
Order
Passeriformes
Pelecaniformes
Passeriformes
Passeriformes
Passeriformes
family
Fringillidae
Ardeidae
Turdidae
Corvidae
Corvidae
Genus
Cardinal
Ardea
Sialia
Corvus
Cyanocitta
1
2
3
4
5
Organisms 4 and 5
Evidence: these two organisms have similarities through
the family level of organization.
Kingdom
Animal
Animal
Animal
Animal
Animal
Phylum
Chordata
Chordata
Chordata
Chordata
Chordata
Class
Aves
Aves
Aves
Aves
Aves
Order
Passeriformes
Pelecaniformes
Passeriformes
Passiformes
Passeriformes
family
Fringillidae
Ardeidae
Turdidae
Corvidae
Corvidae
Genus
Cardinal
Ardea
Sialia
Corvus
Cyanocitta
Cardinal
Heron
Blue Bird
Crow
Blue jay
Taxonomy: the branch of science that classifies organisms based
on structural and microbiological similarities
What is the importance of genetic variation in
the survival and reproduction of a species?
What is the importance of genetic variation in the
survival and reproduction of a species?
Genetic variation allows a species to change in
response to changes in the environment.
Without these variations, a species would face
extinction if the environment changes and new
adaptations are required. Example: rock pocket
mice with pale fur and dark fur. The environment
changed to a dark, lava substrate. If there were
not variation in fur color, all pale fur mice would
have been killed by predators. No survivors over
Which organisms share the trait of seeds?
Which organisms share the trait of seeds?
Oak and Yew
Difficulty solving this?
Use the “snip” method.
Imagine you have cut the
Cladogram tree just below
the trait hash mark. Every
organism that would “fall off”
below the cut does NOT have the
trait, those that remain in the tree
above the cut HAVE the trait.
Which organisms share the trait of seeds?
Oak and Yew
These two organisms
are the only ones that remain
in the Cladogram tree when
it is cut below the “seeds”
hash mark.
Difficulty solving this?
Use the “snip” method.
Imagine you have cut the
Cladogram tree just below
the trait hash mark. Every
organism that would “fall off”
below the cut does NOT have the
trait, those that remain in the tree
above the cut HAVE the trait.
Which organisms share the trait of losing their leaves?
(loss of leaves)
Which organisms share the trait of losing their leaves?
(loss of leaves)
Psilotum