Evidence of Evolution
Download
Report
Transcript Evidence of Evolution
Evidence of Evolution
Chapter 15
Part II
1. Fossil Record
Are able to observe links between modern forms and
ancestors (ex. transition species)
Relative age- age compared to other fossils by
referring to the geologic time scale and records of
known fossils
Absolute age- use of radiometric dating to date rocks
2. Biogeography
Geographical distribution of species
New organisms arise in same geographic
area where similar forms already lived
Example) Australia – has native wolves, cats,
mice, moles, and anteaters. Most mammals are
marsupials (animals evolved in isolation)
Ex) Ancient Irish Elk
Ex) European Elk
3. Anatomy and Embryology
Homologous structures- anatomical structures
that occur in different species that originated
in most recent common ancestor
may have different functions but look similar
Common Ancestor:
Human
Bat
Analogous Structuresa body part similar in function to another
organism due to environmental pressures
Ex) the wings of a fly, a moth, and a bird developed
independently as adaptations to a common function –
flying
Analogy vs. Homology
Vestigial structures- a part of an
organism with little or no function but
which had a function in an ancestral
species
Comparative Embryology- Study of
structures that appear during embryonic
development
Ex)All vertebrate embryos go though a stage in
which they have gill pouches on the sides of
their throats
NOVA | Guess the Embryo
4. Molecular Biology (DNA and Proteins)
Comparison of DNA, RNA, and amino acid
sequences
Greater the number of similarities, the more closely
the species are related through a common ancestor
Shows the common descent of the most diverse
organisms.
Amino Acid Chart
Evidence of Evolution:
fossil evidence, homologous structures, embryology,
vestigial organs, biochemical
Bones in bird’s wing and human’s arm are similar in
structure.
All organisms use ATP to transfer energy.
There are similarities in structure among the early
stages of fish, birds and humans.
Humans, unlike rabbits, have no known use for
their appendix.
Horses have increased in size and decreased in
number of toes since the Eocene.
Phylogeny
The relationships by ancestry among
groups of organism
Represented by the “Tree of Life”
Different evidence supports different
“trees”
Patterns of Evolution
1. Coevolution
2. Convergent Evolution
3. Divergent Evolution
1. Coevolution
When two or more species have evolved
adaptations that influence each other
(evolutionary “arms race”)
Examples:
Predator-prey
Parasite-host
Plant-animal pollinator (bee and flower)
Humans have developed and used
antibiotics to kill bacteria, bacteria have
evolved to become antibiotic resistant
2. Convergent Evolution
Organisms appear to be similar but are not
closely related at all
The environment selects similar traits
Result in analagous structures
Ex) dolphin and shark
3. Divergent Evolution
Two or more biological characteristics
become more and more dissimilar in
response to different habitats
Adaptive radiation- a new population in a
new environment (island) will undergo
evolution until the population fills many
parts of the environment
Ex) Galapagos finches
Caribbean Anole Lizards
Artificial Selection
The intentional breeding (by humans) of certain
traits, or combination of traits, over others