Changes in the genetic makeup of populations
description
Transcript of Changes in the genetic makeup of populations
![Page 1: Changes in the genetic makeup of populations](https://reader035.fdocuments.in/reader035/viewer/2022062315/5681668e550346895dda6088/html5/thumbnails/1.jpg)
Changes in the genetic makeup of populations
![Page 2: Changes in the genetic makeup of populations](https://reader035.fdocuments.in/reader035/viewer/2022062315/5681668e550346895dda6088/html5/thumbnails/2.jpg)
Natural Selection1.Populations
tend to overproduce offspring.
![Page 3: Changes in the genetic makeup of populations](https://reader035.fdocuments.in/reader035/viewer/2022062315/5681668e550346895dda6088/html5/thumbnails/3.jpg)
Natural Selection
2. Genetic variation exists within populations
![Page 4: Changes in the genetic makeup of populations](https://reader035.fdocuments.in/reader035/viewer/2022062315/5681668e550346895dda6088/html5/thumbnails/4.jpg)
Natural Selection3. The best adapted organisms survive and reproduce in
greater numbers.
![Page 5: Changes in the genetic makeup of populations](https://reader035.fdocuments.in/reader035/viewer/2022062315/5681668e550346895dda6088/html5/thumbnails/5.jpg)
Natural Selection4. Subsequent generations
contain higher frequencies of adapted orgs.
![Page 6: Changes in the genetic makeup of populations](https://reader035.fdocuments.in/reader035/viewer/2022062315/5681668e550346895dda6088/html5/thumbnails/6.jpg)
Adaptation Inherited trait
Increases chance of survival/reproduction
Environment-specific
![Page 7: Changes in the genetic makeup of populations](https://reader035.fdocuments.in/reader035/viewer/2022062315/5681668e550346895dda6088/html5/thumbnails/7.jpg)
Natural SelectionThe environment determines success of traits
1.Overproduction2.Genetic variation3.Struggle for survival4.Differential reproduction
![Page 8: Changes in the genetic makeup of populations](https://reader035.fdocuments.in/reader035/viewer/2022062315/5681668e550346895dda6088/html5/thumbnails/8.jpg)
Natural Selection
![Page 9: Changes in the genetic makeup of populations](https://reader035.fdocuments.in/reader035/viewer/2022062315/5681668e550346895dda6088/html5/thumbnails/9.jpg)
Hardy-Weinberg Conditions
Hypothetical conditions that must exist in a population for no evolution to
occur.
![Page 10: Changes in the genetic makeup of populations](https://reader035.fdocuments.in/reader035/viewer/2022062315/5681668e550346895dda6088/html5/thumbnails/10.jpg)
Population CharacteristicsHinder Evolution(Hardy-Weinberg Conditions)
Infinitely Large
Random Mating
Equal Survival
Isolation
No mutations
Help Evolution(Natural Conditions)
Small Genetic Drift
Natural Selection
Natural Selection
Gene Flow
Mutations
POPULATION SIZE
MATING
VIABILITY
INTERACTION W/ OTHER POPS
DNA CHANGES
![Page 11: Changes in the genetic makeup of populations](https://reader035.fdocuments.in/reader035/viewer/2022062315/5681668e550346895dda6088/html5/thumbnails/11.jpg)
Genetic DriftRandom fluctuations in genetic makeup
Example: 2 red, 2 blue orgs seek shelter 50% survive. All are red Blues eliminated by chance (17%)
4 red, 4 blue head for shelter 50% survive. All are red Blues eliminated by chance (1.4%)
![Page 12: Changes in the genetic makeup of populations](https://reader035.fdocuments.in/reader035/viewer/2022062315/5681668e550346895dda6088/html5/thumbnails/12.jpg)
Genetic DriftBottleneck Effect
Catastrophe cuts pop size Decreased variety of traits Altered genetic makeup Genetic drift more likely
Founder Effect
Small group emigrates to new habitat
![Page 13: Changes in the genetic makeup of populations](https://reader035.fdocuments.in/reader035/viewer/2022062315/5681668e550346895dda6088/html5/thumbnails/13.jpg)
Gene Flow Introduction of new traits through immigration May be beneficial or insignificant New traits altered genetic makeup
![Page 14: Changes in the genetic makeup of populations](https://reader035.fdocuments.in/reader035/viewer/2022062315/5681668e550346895dda6088/html5/thumbnails/14.jpg)
Modes of Selection Stabilizing
Environment is stableInitially adaptive form
becoming more numerous from many generations of natural selection RANGE OF PHENOTYPES
MOST ADAPTIVE FORM
![Page 15: Changes in the genetic makeup of populations](https://reader035.fdocuments.in/reader035/viewer/2022062315/5681668e550346895dda6088/html5/thumbnails/15.jpg)
Modes of Selection Directional
Environment is changing (or has changed)
Formerly adaptive form is no longer adaptive
Pop evolves toward newly adaptive form
MOST ADAPTIVE FORM
RANGE OF PHENOTYPES
![Page 16: Changes in the genetic makeup of populations](https://reader035.fdocuments.in/reader035/viewer/2022062315/5681668e550346895dda6088/html5/thumbnails/16.jpg)
RANGE OF PHENOTYPES
Modes of Selection Disruptive
(Diversifying)Intermediate form is
undesirable and decreases in #
MOST ADAPTIVE
FORMS
MOST ADAPTIVE
FORMS
![Page 17: Changes in the genetic makeup of populations](https://reader035.fdocuments.in/reader035/viewer/2022062315/5681668e550346895dda6088/html5/thumbnails/17.jpg)
Evolution of the Ctukis Ctukis are creatures from a planet you’ve never
heard of. You will construct a ctuki out of a single 8½x11
sheet of paper.Do not add any materials.Put your names on the ctuki.Your ctuki must be able to asexually reproduce in class
(it should take no more than one minute).