1. EVOLUTION and SPECIATION

2. Gene Pool Combined genetic information (traits) of all members
Allele frequency is number of times traits occur

3. Variation in Populations
2 processes can
lead to this:
Mutations -
change in DNA
sequence
Gene Shuffling –
from sexual
reproduction

4. Genetic Drift changes populations
Random change in allele frequency causes an allele to become common

5. Founder Effect: a cause of genetic drift caused by a limited number of individuals separating from a parent population

6. Gene Flow: genetic exchange due to the migration of fertile individuals or gametes between populations (reduces differences between populations)

7. Nonrandom mating: inbreeding and assortive mating (both shift frequencies of different genotypes)

8. Natural Selection: environment acts upon populations and determines traits best fit for success.

9. Sexual selection
Sexual dimorphism: secondary sex characteristic distinction
Sexual selection: selection towards secondary sex characteristics that leads to sexual dimorphism

10. Genetic Change in Populations
Occurs when there is a change in the relative frequency of alleles

11. Phenotype Expression
Depends on how many genes control that trait

12. Single-Gene vs. Polygenic Traits
2 Distinct Phenotypes
Polygenic:
Many Phenotypes
(EG: tongue rolling)

13. Natural Selection: Peppered Moth

14. Conditions needed for Genetic Equilibrium

15. SPECIATION THE FORMATION OF A NEW SPECIES
IF NEW SPECIES EVOLVE, THE POPULATIONS BECOME REPRODUCTIVELY ISOLATED
REPRODUCTIVE ISOLATION – MEMEBERS OF TWO POPULATIONS CANNOT INTERBREED AND PRODUCE FERTILE OFFSPRING (HYBRIDS)

16. 3 ISOLATING MECHANISMS……..
BEHAVIORAL ISOLATION- CAPABLE OF BREEDING BUT HAVE DIFFERENCES IN COURTSHIP RITUALS (Example: MEADOWLARKS)
GEOGRAPHICAL ISOLATION – SEPARATED BY GEOGRAPHIC BARRIERS LIKE RIVERS, MOUNTAINS, OR BODIES OF WATER (Example: SQUIRREL)
TEMPORAL ISOLATION – TWO OR MORE SPECIES REPRODUCE AT DIFFERENT TIMES OR SEASONS

18. Fig. 23.6
Four species of leopard frogs: They differ in their mating calls. Hybrids are inviable (die).

19. These squirrels live on opposite sides of the Grand Canyon
These squirrels live on opposite sides of the Grand Canyon. This is an example of allopatric speciation.

20. Table 23.1a

21. Table 23.1b

22. Tigon
Result of male tiger and female lion mating in captivity. Offspring are infertile.
Separated both geographically and ecologically.

23. Liger
Result of male lion and female tiger mating in captivity. Offspring are infertile.

24. Hawaiian Honeycreepers
An possible example of adaptive radiation.
These species may have diverged from a
common ancestor (founder species).
FOUNDER SPECIES

25. SPECIATION IN DARWIN’S FINCHES
SPECIAITON IN THE GALAPAGOS FINCHES MAY HAVE OCCURRED BY:
- FOUNDING OF A NEW POPULATION,
- GEOGRAPHIC ISOLATION which led to -- REPRODUCTIVE ISOLATION and
CHANGES IN THE NEW POPULATION’S GENE POOL due to COMPETITION.

27. Evidence Cited for Evolution
Fossil Record
Geographic Distribution of Living Species
Homologous Body structures
Similarities in Embryology

28. Evidence of
Evolution?
Fossil Record provides evidence that living things have become extinct
Fossils show the history of life on earth and how different groups of organisms have survived over time

29. Marsupial Mammals Convergent Evolution Placental mammals and
Flying Squirrel
Sugar Glider
Marsupial Mammals
Convergent Evolution
and
Analogous Structures
Placental mammals
Mammalia
Rat-like common ancestor?

31. Haeckel’s Drawings