evidence of evolution & patterns of evolutionevidence of evolution 1. biogeography –plate...
TRANSCRIPT
Evidence of Evolution &
Patterns of Evolution
Honors Biology
Evidence of Evolution
1. Biogeography – Plate Tectonics
2. Fossil Record
3. Comparative Anatomy - Vestigal
Structures
4. Comparative Anatomy -
Homologous/Analogous structures
5. Embryology
6. Molecular Biochemistry
1. Biogeography
• Geographical
distribution of species.
• Organisms tend to
arise in areas where
similar organisms
lived in the past.
2. Evidence from Fossils
• Scientists study fossils to obtain a record of the successive changes organisms have undergone.
• Fossils demonstrate change over time, the change is from simple to complex, and show the relative ages of two specific fossils.
• Evidence is not complete and can be easily disrupted.
What can be learned about an organism by
studying fossil skulls?
The size of the brain
As a species evolves, the size of the brain will
enlarge.
Law of
Superposition
Fossils and the rocks in which
they appear are in
chronological order from
oldest at bottom to youngest
at top. (strongest evidence)
Dating Fossils
Relative Age
describes approximate age of fossil relative to location.
Ex. “This fossil is located beneath that fossil, so it is relatively older.”
Law of superposition
Absolute age
Age of a fossil in years
Can be calculated
using radioactive
dating
Ex. “This fossil is
approximately 1
million years old.”
3. Evidence from Adaptations Traits suited to a particular environment that
allow organisms to survive
Inuit people, who live in the extreme cold of the Arctic, have short, stout bodies that conserve heat.
Masai people, who live in the arid lands of eastern Africa, have tall, lean bodies that disperse heat well.
Examples of AdaptationsInsecticides – Over the years many insects have become
resistant to the type of insecticides we have been using.
Why?
Species change – if a insect is susceptible to the insecticide they
will die, the ones that are not survive and continue to reproduce.
Round-Up Ready Crops – crops have been genetically
engineered to be resistant to round up, allowing the spray
to be used and not controlled by what it touches
These plants can get out in the wild or crossbreed creating “super
plants” that can no longer be controlled
Antibiotics – These are used to fight bacterial infections,
but have become less successful in some cases. Why?
The bacteria that are susceptible die of, leaving on the strong ones
to grow and multiple
Bird Beak Adaptations:
Adaptation vs. Acclimation
Adaptation (Evolution)Inherited characteristics of
organisms that enhance their
survival and reproduction in a
specific environment.
Acclimation
A physical change that
allows an organism to cope
with changed condition.
4. Evidence from Comparative
Anatomy
Structural similarities link related
species
Homologous/Analogous Structures
Vestigial Structures
Demonstrate how closely related
organisms are and how close their
common ancestor might be
Comparative Anatomy
Structures:
Homologous Structures: structures that are
similar because of common ancestry and
develop similarly
Traits of Homologous Structures:
1. Same ancestor
2. Same underlying structures
3. Different Functions
4. Different Environments
Examples of Homologous Structures
Homologous Structures:Same underlying structures, different functions,
different environments & common ancestor
Comparative Anatomy Structures:
Analogous:
1. Different ancestors
“analogy”=like
2. Different underlying
structures
3. Same Function
4. Similar Environments
Homologous:
1. Same ancestor
“homo”=same
2. Same underlying
structures
3. Different
Functions
4. Different
Environments
Comparative Anatomy
Structures:
Vestigial Structures
Structures that are present but not used by organism
Structures may have been useful to ancestors
These structures show a change has occurred over time
Examples:
In humans: tailbone, appendix
In whales: pelvic bone and four chambered
stomach
In snakes: pelvic bone, limb bones
5. Comparative Embryology
• Study of structures that appear during embryonic development.
• Embryos of different vertebrates show similar embryo development
5. Comparative Biochemistry
The more DNA
sequences species
have in common,
the closer they are
related
Molecular
Connection Lab
Differences in Biochemistry
DNA and proteins (amino acids)
Mutations are changes in the DNA.
Gene flow due to Immigration/Emigration
Gene flow is any movement of genes from one
population to another.
Immigration – into a population
Emigration – out of a population
Sexual Reproduction
Patterns of Evolution
Coevolution
Convergent Evolution
Divergent Evolution
Coevolution
The change in 2 or more species that are
closely associated with each other
Example:
• Acacia ants and acacia trees
• Humming birds and plants with flowers with long
tubes
Convergent Evolution
Species from different evolutionary branches may come to resemble each other even though they are not closely related
Example:
1. Ostrich (Africa) & Emus (Australia).
2. Sidewinder (Mojave Desert) &
Horned Viper (Middle East Desert)
3. Sharks and Dolphins
Divergent Evolution
2 or more species or related population
become more and more dissimilar
Can result in a new species
Types:
Adaptive radiation: related species evolve from
a single ancestral species (Galapagos finches)
Artificial selection: breeding organisms for
specific trait (dogs)
Final Thought:
Is it possible to develop an advantageous
characteristic within your own lifetime and
pass it on to your offspring?
Explain why or why not.