Download Evolution

Evolution
• Evolution is the
change in genes in a
population over time
• Evolution helps us
understand the
history of life
• Present-day species
evolved from earlier
species
What is a population?
Members of the same
species living in a certain
location at a specific time
Evolution does NOT take
place in an individual
The changes in the genes
(sections of DNA) must
be passed on to another
generation
Types of evidence used to support the
Theory of Evolution:
A.
B.
C.
D.
E.
Biogeography
The Fossil Record
Embryology
Comparative Anatomy
Biochemical Analysis
Biogeography
• The study of where
species are located
on the Earth
• Organisms change
over time due to
environmental
changes/stresses
A. Biogeography
Organisms found on islands
share features with
species on the mainland
– Galapagos Islands
• Finch birds
• Tortoises
Islands with similar
environments have
similar species
Adaptations
Organisms change over time due
to environmental stresses
Three types of
adaptations:
• Structural
• Behavioral
• Physiological/function
B. Fossil Record
Paleontologists study records
Fossil records reveal the chronological order of
vertebrates is:
1.
2.
3.
4.
5.
FISH first appeared on Earth then came…
AMPHIBIANS
REPTILES
BIRDS
MAMMALS
Types of fossils
•
•
•
•
•
•
Imprint
Mold
Casts
Petrified samples
Frozen samples
Amber—sap from
trees
C. Comparative Embryology
• Study of early stages of development before birth
Timing of stages and new features reveals
evolution/history of ancestors
• New features in different organisms came from the
remodeling of ancestral structures
Examples:
– jaws and inner ears develop from gill slits
Gill slits in red
Gills still
present in
fish and
some
salamanders
Embryology and Fossils
• Snakes have legged
ancestors
– Some species have hind (rear)
limb buds as early embryos
– They lose the buds and develop
into legless adults
– Fossil evidence of snakes with
hind limbs exists
– Suggests snakes evolved from a
limbed ancestor
D. Comparative Anatomy
Do birds have phalanges?
Do cats have lumbar vertebrae?
Do frogs have a humerus bone?
Scientists study homologous, analogous, and
vestigial structures to show evolutionary
relationships
Homologous Structures
– Share the same pattern of
structure—arm bones
– Have a recent common
ancestor
– Come from the same part
of the embryo
– May or may not perform
the same function
Analogous Structures
– Body part different in
structure such as
wings
– Share a different origin
and development
– Yet similar in function
Vestigial Structures
Fully developed in some organisms,
yet reduced or functionless in others
Examples:
– Hip bones in snakes and hip bones in
humans
– Eyes in blind cave fish
E. Biochemical analysis
Molecular level living things are very
similar
• DNA/RNA code
• proteins for building blocks
• ATP for energy
• sugars for fuel
• genes for traits
Biochemical analysis
--Protein synthesis follows the same
process in eukaryotes
DNARNARibosomesProteins
--Roundworms share 25% of their
genes with humans
Biochemical analysis
Examples:
--Insulin may control sugar levels in
numerous species
--Animal cells and plant cells use
glucose for making energy
Evolutionary pattern of the
Animal Kingdom
ProtocellsProkaryotesEukaryotes
ProtistsInvertebratesVertebrates
Evolution Review
• What is the definition of evolution?
• What are the types of evidence for
evolution?
• Describe (explain and provide examples)
of each type of evidence.
• What is the evolutionary pattern for
members of the animal kingdom?
• Organisms are grouped based on_____?
Classification of organisms
• Organisms are
• The study of
grouped based on
classification is
similarities such
called taxonomy
phenotypes and
evolutionary history