1. EVOLUTION! Summing it all up!

2. What is Scientific Theory?
In science, theories are statements or models that have been tested and confirmed many times.

3. They explain a wide variety of data and observations
In science, the term "Theory" does not express doubt.
They explain a wide variety of data and observations
They can be used to make predictions
They are not absolute, can be changed as new evidence is found

4. The theory of evolution is considered a UNIFYING THEORY of Biology, because it answers many questions and offers an explanation for observations

5. History of Evolution
Charles Darwin developed the THEORY OF EVOLUTION BY NATURAL SELECTION
explained how organisms changed over time  (ADAPTED)

6. Acquired Characteristics
Lamarke's Theory of Acquired Characteristics
Some thought that you would gain or lose features if you overused or didn't use them,
 PROVEN TO BE WRONG!

7. Macroevolution: Evolution of a New Species

8. Levels of Evolutionary Study
Microevolution: examines changes to the genes (alleles) within populations
Population Genetics: studies the changes in the numbers & types of alleles in a population
Examines evolution within a species.
Small changes that do not lead to new species, but can lead to new variations.
Macroevolution: examines the evolutionary changes that create new species
Speciation: the formation of new species over time

9. Macroevolution
Species: a group of organisms that can interbreed and produce fertile offspring
Speciation: the evolution of new speices (by genetic change or change in form)
Occurs when members of a similar populations can no longer interbreed!

10. Methods of Speciation
Geographic Isolation: physical barriers divide a population and prevent interbreeding
Beetles in Grassland Become Green
Beetles in Woody Habitat
Become Brown

11. Methods of Speciation
Reproductive Isolation--occurs when formerly interbreeding organisms can no longer mate & produce fertile offspring
Genetic: genetic differences are too great to breed successfully
Behavioral: mating behaviors or mating seasons don’t allow for mating
Chromosome Numbers
Polyploidy: any species with extra sets of chromosomes. Common in plants.
Can interbreed or self-fertilize, forming separate species
Hybridization: when two closely related species attempt to mate
Usually results in sterile offspring
Ex: donkey + horse = mule

12. Speed of Speciation Gradualism Punctuated Equilibrium
Idea that species originate thru a slow, gradual change of adaptations over long periods of time
Punctuated Equilibrium
Idea that species can remain stable for long periods of time until environmental changes cause many new species to appear
Speciation occurs in less than 10,000 years!

13. Patterns of Macroevolution: Divergent Evolution
Species diverge or become increasingly distinct from one ancestral species
Ex: Darwin’s finches
Also called adaptive radiation

14. Patterns of Macroevolution: Convergent Evolution
Process by which unrelated species become similar as they adapt to similar environments
Ostrich
Rhea
Emu
Australia
South
America
Africa

15. Patterns of Macroevolution: Coevolution
When species who live in close contact evolve adaptations to one another’s existence.

16. Extinction!
When all the members of a species die off or fail to reproduce
Estimated that 99% of all species that ever lived have become extinct
Most extinctions are the
result of environmental
change, can cause well
adapted species to become
poorly adapted!
If the environment changes
faster than a species can adapt,
extinction can result!

17. Microevolution

18. Processes of Microevolution
Microevolution examines the processes by which inherited traits change over time in a population
Natural Selection
Migration
Mate Choice
Mutation
Genetic Drift

19. Processes of Microevolution
Natural Selection: changes in environmental pressures can cause an increase or decrease in certain alleles (traits) in a population
Favorable alleles stay in population (selected for)
Unfavorable alleles are eliminated (selected against)
Migration: as organisms move from one population to another, their genes move with them
Causes the numbers and types of alleles within each population to change.

20. Processes of Microevolution
Mate Choice: if parents are selective (picky) or limited in their choice of mates, only a limited set of traits will be passed on
Mutation: can add a new allele to a population
Mutations are rare, and must occur in egg or sperm to be passed on
Genetic Drift: population sizes affect the change in alleles (traits) in a population
Large populations experience slower changes in alleles
Smaller populations can change more quickly

21. Changes within Populations
Microevolution:
Changes within Populations
Populations evolve NOT individuals evolve
Natural selection works on the phenotypes within a population
Individuals cannot evolve within their lifetime, because they cannot evolve a new phenotype due to a change in the environment
Evolution is brought about by breeding that occurs between organisms within a population. Natural selection maintains favorable (useful) genotypes, and eliminates unfavorable (not useful) genotypes.

22. - Explains how organisms change over time
Natural Selection
- Explains how organisms change over time
Over Production: Most organisms produce more offspring than will survive
Variation: Members of the population have variations
Selection: Certain variations will increase the likelihood of survival
Adaptation: Over-time organisms with that variation make up most of the population and may look different than their ancestors

23. Patterns of Natural Selection
Directional selection:
Favors EXTREME variations; evolution is fast
Stabilizing selection:
Favors average individuals; reduces variation
Disruptive selection:
Favors two extreme variations; no intermediate and eventually two species.

24. Stabilizing Selection
“Average” individuals are better able to survive
Alleles for the “extreme” are eliminated
A narrow range of
phenotypes is favored
resulting in a narrow
bell shaped curve

25. Directional Selection
ONE extreme is favorable, but other is not
Alleles for other extreme and normal phenotypes become less common in the population
Results in FAST
evolution!
Bell curve is shifted
off of center

26. Disruptive Selection BOTH extremes are favorable!
Results in increasingly distinct phenotypes, the “normal” phenotype is selected against
Bell curve is
‘disrupted’ and
pushed apart
into two peaks

27. Evidence for Evolution

28. Evidence for Evolution
Fossils
provide a record of early life & evolutionary history
Currently, the fossil record is incomplete (like a jigsaw puzzle w/ missing pieces)
The more fossils discovered, the clearer the evolutionary picture becomes!

29. Evidence for Evolution
Biogeography
The study of the locations of organisms around the world
Organisms in similar
environments have
similar adaptations
despite being on
completely different
continents.
Ex: Large, flightless birds

30. Evidence for Evolution
Anatomy
the way an organism is put together
Homologous structures
Analogous Structures
Vestigial Structures

31. Homologous Structures
Parts with a common evolutionary history
Ex: Organisms that have the same basic skeleton, bones are just modified for different functions
It would be unlikely
for so many animals
to have similar
structures if each
species arose
individually!

32. Analogous Structures
Body parts that are similar in function, but not evolutionary origin
Ex: Wings of a butterfly & wings of a bird

33. Vestigial Structures
Body structure that has no function in present day organisms, but was probably useful to an ancestor
Ex: Eyes on Naked Mole Rats, Appendix in humans, Wings on ostrich

34. Evidence for Evolution
Adaptations: Structural
Develop over many generations (ex: claw length, fur color, etc)
Mimicry: enables one species to resemble another species. Monarchs and Viceroys
Camouflage: enables species to blend in with their surroundings
Monarch
TOXIC!
Viceroy
TASTY!

35. Evidence for Evolution
Adaptations: Physiological
Changes in an organisms metabolic processes (occurs more rapidly)
Bacteria’s resistance to antibiotics
Insects / weeds
resistance to
certain
pesticides

36. Evidence for Evolution
Embryological
similarities between young embryos suggest evolution from a distant common ancestor

37. Evidence for Evolution
Biochemical
Provides info about relationships between individuals and species
Uses RNA & DNA sequences to construct cladograms (evolutionary diagrams)