1. HW: IP: Evolution & Genetics
Wednesday
May 3, 2017
I can:
explain how changes in DNA lead to evolution
Agenda
(10) Catalyst
(45) Biochemical Similarities in Vertebrates
(15) GN: Evolution and Genetics
(15) IP: Evolution & Genetics
Catalyst
What is the BEST type of evidence for evolution?
What type of evidence compares nucleic acids?
This type of evidence has to do with body structure.
This type of evidence has to do with development of fetuses.
HW: IP: Evolution & Genetics

3. Exit Ticket Review
The process by which organisms with favorable variations reproduce at higher rates than those without such variations is
Disruptive selection
Natural selection
Sexual selection
Directional selection

4. Exit Ticket Review
Natural selection is a mechanism that acts on individuals within a population. Which is a result of the process of natural selection?
The reproductive rate of the population decreases
Genetic similarity within the population increases
Organisms are better adapted to their environment
Adverse changes to the environment become more frequent

5. Exit Ticket Review
Darwin’s studies of the finches on the Galapagos Islands suggest that the finches’ differences in beak structure were most directly due to what?
The size of the island where the finches live
Acquired characteristics in the parent finches
Mating behaviors of the different finch species
Adaptations of the finches to varying environments

6. Exit Ticket Review
Which is the best description of how natural selection changes a species over time?
Survival of the strongest organisms in the environment
Elimination of the smallest organisms by largest organisms
Survival of the organisms genetically best adapted to the environment
Survival of the organisms that occupy the largest area in an environment

7. Exit Ticket Review
1. What is the best way to determine the evolutionary relationships between species?
A. by comparing their bone structures
B. by comparing their physical appearance
C. by comparing the amino acid sequences of their proteins
D. by comparing fossils that resemble the organisms to identify common ancestors

8. Exit Ticket Review
2. Archaeoptryx was discovered two years after Darwin published On the Origin of Species. Archaeoptryx had a long, bony tail like dinosaurs, broad wings and feather like birds, and skeletal features of both. What best describes this evidence? A. fossil B. geological C. biochemical D. embryological

9. Exit Ticket Review
3. Which could give the best biochemical evidence of evolution?
A. lipids
B. fossils
C. nucleic acids
D. carbohydrates

10. Exit Ticket Review
4. The forelimbs of living whales, dogs, humans, and bats are all similar in their arrangement and structure. What category of evidence is exemplified? A. fossils B. anatomical similarities C. biochemical comparison D. embryological comparison

11. Exit Ticket Review
5. What can be inferred from the following statement? The protein cytochrome c is found in all aerobic organisms. A. Living things have not evolved. B. All living things will evolve to be aerobic. C. Aerobic organisms evolved from a common ancestor. D. Anaerobic organisms will evolved into aerobic organisms.

12. Evolution is CHANGE over TIME
REMEMBER:
Evolution is CHANGE over TIME

13. Evolution requires these four things (VSIT):
Variation – differences between individuals in a species

14. Evolution acts on variation that is already present in a population!

15. I only eat green beetles!
Evolution requires these four things (VSIT):
Selection – some individuals have greater fitness than others in the environment and will survive better
A trait that is selected for is one that is beneficial to the organism. A detrimental trait is selected against.
I only eat green beetles!
The brown beetles have greater fitness in this environment, because they are not eaten. They are able to survive and reproduce.

16. Evolution requires these four things (VSIT):
Inheritance – the traits that result in greater fitness can be passed on to offspring

17. Evolution requires these four things (VSIT):
Time – many, many generations must pass

18. different DNA  different protein  different trait
We can now understand how evolution works better than Darwin ever could. Now we know genes are the units of heredity, and they are what explain genetic variation.
straight fur
curly fur
different DNA  different protein  different trait

19. …but where does genetic variation come from?
Genetic variation is studied at the population level.
In genetic terms, evolution is any change in the relative frequency of alleles in a population
…but where does genetic variation come from?
the relative frequency of an allele is the number of times that it occurs as a % of the total # of alleles in the gene pool

20. Genetic variation comes from two sources: mutations
does not always affect phenotype
gene shuffling during meiosis
crossing-over introduces new combinations of genes
independent assortment creates new combinations of traits

21. sometimes a mutation will not affect the phenotype because many codons code for the same amino acid

22. Remember, it is populations, not individual organisms, that can evolve.
gray squirrel
black squirrel

23. Natural selection is not the only source of evolution.
Genetic drift is the random change in allele frequency due to small population size.
aka bottleneck effect
The population of beetles is very small.
A catastrophic event kills off most of the green beetles, by chance.
Now there is a greater frequency of the brown allele than before due to genetic drift.

24. The founder effect is an example of a bottleneck effect.
a small group of individuals starts a new population with a different allele frequency from the original population

25. equal chances? When will evolution NOT occur?
The Hardy-Weinberg principle states that allele frequencies in a population will remain constant if, and only if, the following conditions are met:
1. Mating is random. (Does this happen with humans?)
equal chances?

26. 2. Population is very large (so genetic drift can’t occur).
3. No movement into or out of the population.
4. No mutations.
5. No natural selection.

27. Certain species that depend on each other can coevolve
Certain species that depend on each other can coevolve. Coevolution occurs when the evolution of one species affects the evolution of another.