evolution evolution is the change in genes in a population over time evolution helps us understand...
TRANSCRIPT
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. Biogeography
B. The Fossil Record
C. Embryology
D. Comparative Anatomy
E. 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
AdaptationsOrganisms 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. FISH first appeared on Earth then came…2. AMPHIBIANS3. REPTILES4. BIRDS5. 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
DNARNARibosomesProteins
--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
ProtocellsProkaryotesEukaryotes
ProtistsInvertebratesVertebrates
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 grouped based on similarities such phenotypes and evolutionary history
• The study of classification is called taxonomy