Evolution

1
Evolution

• Changes Over Time

2
Adaptations

• What are they?
• characteristics or behaviors that help an
  organism to survive

3
Evolution

• Definitions
• The accumulation of changes over generations
• The change in the frequency of a particular trait
  within a population
• Populations evolve not a single organism
• Driving Forces
• Natural Selection
• Competition

4
Whats a Species?

• Definition
• a group of organisms that can successfully
  reproduce to produce viable offspring
• At some point in time two species will split far
  enough apart that they can no longer interbreed.
  Creates a new species.

5
Charles Darwin

• Who?
• British Naturalist
• Dad wanted a Dr.
• didnt like surgery
• What?
• sailed to the Galapagos in 1831 on HMS Beagle
• 5 yr. global voyage
• published the Origin of Species

6
Did Darwin do this alone?

• Darwin used the work of others to help support
  his findings.
• Alfred Wallace
• Charles Lyell
• Waited 20 yrs between the Beagle and the Origin
  of Species.
• Why?

7
Alfred Wallace

• Who?
• Amateur scientist
• no formal training
• What
• Studied insects
• Unknowingly pushed Darwin to publish the Origin
  of Species
• Where?
• Explored the Amazon River Basin

8
Charles Lyell

• English Naturalist and geologist
• Informal research
• Found evidence that natural processes shape the
  earth over large time spans
• Gave the foundation for Darwin

9
Selective Breeding

• What?
• Selection by human hands
• choose organisms with traits we want to breed
  together.
• Examples
• Horses
• Dogs

10
Does Population Matter?

• Overpopulation drives natural selection
• Why?
• Population size increase less resources
• Survivors well adapted organisms

11
Natural Selection

• Four Steps
• Overproduction
• (overpopulation)
• Genetic Variation
• (mutation)
• Competition
• Successful reproduction

Driven by Competition
12
Punctuated Equilibrium

• Evolution is not a gradual process
• Evolution occurs in short quick bursts based on
  environmental change.

13
Natural Selection in Action

• Examples
• Insecticide Resistance
• Antibiotic Resistance
• Adaptation to Pollution
• Darwins Finches
• Can you think of any others?

14
CockroachesTough little buggers
Generation Time The period of time between the
birth of one generation and the birth of the next
15
Dirty Forest Dirty Moths
16
Speciation

• Forms when two organisms with a common ancestor
  can no longer interbreed.
• 3 steps
• Separation
• Adaptation
• Division (new species)

17
Galapagos Finches
18
Branching Trees
19
Bacteria to Humans
20
Evidence for Evolution

• The theory of evolution is supported by a variety
  of evidence.
• The Fossil Record
• Comparative Anatomy

21
Fossils

• What are they?
• solidified remains or imprints of long dead
  organisms
• Types
• Mold
• Bones

22
The Fossil Record

• What is it?
• Collection of all the fossils going back through
  time
• Problems
• Gaps
• Not everything fossilizes (sharks)

23
Back to the Sea A Whales Tail

• Family Trees
• Mesonychid
• 55 MYA
• Ambulocetus
• 50 MYA
• Rodhocetus
• 46 MYA
• Prozeuglodon
• 40 MYA

24
Whats on the Inside?

• Vestigial Structures
• Remnants of once useful structures
• not functional
• Example
• Whales
• Humans

25
Comparative Anatomy

• Many organisms have similar anatomy
• (body structure).
• We can compare
• Skeletons
• DNA
• Embryos

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Skeletal Structures

• Similar anatomy
• yet
• different functions

27
DNA

• All organisms have DNA.
• Small DNA difference between very different
  organisms
• Mutation happen at predictable rate. So we can
  use differences in DNA to determine when
  organisms last had a common ancestor

28
Embryonic Structures

• Many embryos look the same during early
  development.
• What similarities do you see?
• What does that suggest?
• Common ancestors