Download Evidence of Evolution

Evidence of Evolution
Evidence of Evolution
⦿ Homologous Structures:
› Similar features that originate from a
shared ancestor
› look different and have different functions
› skeletal structures (bones) very similar and
are derived from same embryological
structures
⚫ Ex: Forelimbs of animals
Evidence of Evolution
⦿ Analogous Structures:
› Structures that have similar
function, but are genetically
different (different internal
structures)
› Do NOT have a close common
ancestor
› Adaptations that have evolved
to fit similar environments
⚫ Ex: Insect wings and bird
wings
Evidence of Evolution Continued….
⦿
Vestigial Structures:
› Features that exist, but are
no longer used
› Feature that was useful to
an ancestor, but is no
longer useful to the
modern organism
› Ex:
⚫ Human appendix
⚫ Whale and snake leg
bones
Evidence of Evolution
⦿ DNA/RNA (Macromolecules) :
› Compare organisms on a molecular level by using DNA
& RNA
⚫ Determining Relatedness
⚫ Compare the strands of DNA from 2 or more different
organisms.
⚫ The more base pairs that “match” the more related you are
⚫ Differences in DNA sequences are caused by genetic mutations
⚫ Mutations that cause beneficial traits are passed onto offspring
Example:
1. Which organism is more related to a human and
why?
2. What evidence do you have to support your
answer?
Evidence of Evolution
⦿
Fossils:
› Comparing present day organisms to extinct
organisms looking for similarities.
› Relative Dating:
⚫ Using rock layers to determine the approximate age
of fossils.
⚫ Oldest layers are on the bottom, newer fossils on the
top
Evidence of Evolution
Evidence of Evolution Continued….
⦿
Embryology:
› Embryological development repeats
throughout evolutionary history
› Earliest stage of growth and
development
⚫Occurs while still in the egg or womb
Evidence of Evolution
⦿ Embryology:
› Similar genes drive the development of similar
traits during different developmental stages. (In
the animals below, the same gene gets turned on
in early development to create a tail.)
› Development of adult characteristics usually
happens in the late stages of embryology. (In the
animals below, the human tail has receded in
stage III.
›
Embryology
Review of Darwin’s Theory of Evolution
All species descended from one or a few
original types of life.
2. Environment puts pressures on organisms
which limits population growth.
1.
› Natural Selection:
⚫ Organisms best adapted to their environment tend
to survive and transmit their genetic characteristics
more so than those less adapted.
› Survival of the “fittest”.
Darwin’s Evidence
What types of evidence did Darwin use to support his
theory?
› Today’s species are related to extinct species
⚫ Fossils show changes in species over time
⚫ Use of fossils and Relative Dating
› Related species have unique adaptations
⚫ Compared the internal and external structures of
living organisms to the structures of fossils.
⚫ Darwin’s finches have beaks adapted for specific
environments and specific tasks.
Darwin’s Finches
Evidence 2.0
What types of evidence do we use today to support Darwin’s theory?
1.
Use of fossils and Relative dating and Radioactive
Dating
2.
Compared the internal and external structures of
living organisms to the structures of fossils
⚫ Vestigial Structures
⚫ Homologous Structures
3.
Embryology
⚫ comparing early developmental stages of organisms
4.
DNA
⚫ comparing the DNA base pair sequences of organisms.