1. EVOLUTION & SPECIATION

3. VOCABULARY REVIEW EVOLUTION – CHANGE OVER TIME
NATURAL SELECTION - INDIVIDUALS BETTER ADAPTED TO THE ENVIRONMENT ARE ABLE TO SURVIVE & REPRODUCE.
A.K.A. “SURVIVAL OF THE FITTEST”

4. NEW VOCABULARY
POPULATION – GROUP OF INDIVIDUALS OF SAME SPECIES THAT INTERBREED
GENE POOL – COMMON GROUP OF ALL GENES PRESENT IN A POPULATION

5. Gene Pool Combined genetic info. of all members
Allele frequency is # of times alleles occur

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

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

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

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

10. Natural Selection: differential success in reproduction;
adapts a population to its environment

11. Evolution of Populations
Occurs when there is a change in relative frequency of alleles

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

18. Single-Gene vs. Polygenic Traits
2 Distinct Phenotypes
Polygenic: (more than one gene)
Many Phenotypes
(EG: Height)
(EG: tongue rolling)

20. Natural Selection on Polygenic Traits
Shifts to
middle range
2 extremes
1 extreme

22. SPECIATION THE FORMATION OF NEW SPECIES
AS NEW SPECIES EVOLVE, POPULATIONS BECOME REPRODUCTIVELY ISOLATED
REPRODUCTIVE ISOLATION – MEMBERS OF 2 POPULATIONS CANNOT INTERBREED & PRODUCE FERTILE OFFSPRING.

23. 3 ISOLATING MECHANISMS……..
BEHAVIORAL ISOLATION- CAPABLE OF BREEDING BUT HAVE DIFFERENCES IN COURTSHIP RITUALS (EX. MEADOWLARKS)
GEOGRAPHICAL ISOLATION – SEPARATED BY GEOGRAPHIC BARRIERS LIKE RIVERS, MOUNTAINS, OR BODIES OF WATER (EX. SQUIRREL)
TEMPORAL ISOLATION – 2 OR MORE SPECIES REPRODUCE AT DIFFERENT TIMES.

24. Table 23.1a

25. Tigon
Result of male tiger and female lion mating incaptivity. Offspring are infertile.
Separated both geographically and ecologically.

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

30. Table 23.1b

32. Fig. 23.6
Four species of leopard frogs: differ in their mating calls. Reproductive isolation.

33. 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 speciation.

34. Hawaiian Honeycreepers
An example of adaptive radiation –
these species all diverged from a
common ancestor (founder species)
FOUNDER SPECIES

35. SPECIATION IN DARWIN’S FINCHES
SPECIAITON IN THE GALAPAGOS FINCHES 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.

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

39. Evidence of
Evolution
Fossil Record provides evidence that living things have evolved
Fossils show the history of life on earth and how different groups of organisms have changed over time

43. What was early earth like?
Earth was Hot!!
Little or no oxygen
Gasses in atmosphere:
Hydrogen cyanide (poison to you!)
Hydrogen sulfide
Carbon dioxide
Carbon monoxide
Nitrogen
water

44. So how did the earth get oxygen?
Some of that oxygen was generated by photosynthetic cyanobacteria
Some came from the chemical separation of water molecules into oxygen and hydrogen.

45. Others evolved ways of using oxygen for respiration
Oxygen drove some life forms to extinction
Others evolved ways of using oxygen for respiration

46. 3rd Theory of Life Endosymbiotic theory
eukaryotic cells arose from living communities formed by prokaryotic organisms
Ancient prokaryotes entered primitive eukaryotic cells and remained there as organelles