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Please get out a half sheet of paper, not a journal, it’s not a grade. You’ll write down your answers then we will go over to check for understanding. D. A. Living things produce more offspring than will survive. There is variation among the offspring.

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Living things produce more offspring than will survive. There is variation among the offspring.

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Living things produce more offspring than will survive there is variation among the offspring

Please get out a half sheet of paper, not a journal, it’s not a grade. You’ll write down your answers then we will go over to check for understanding


Living things produce more offspring than will survive there is variation among the offspring

D

A

  • Living things produce more offspring than will survive.

  • There is variation among the offspring.

  • Offspring will compete for resources

  • Those that have advantageous traits will survive and reproduce.

  • Those that do not have advantageous traits will die and take poor trait to their grave.

C

E

B

A

E

B

C

D


Living things produce more offspring than will survive there is variation among the offspring

6. Compare the two animals listed below with the human cytochrome C protein segment. Which animal is most similar to humans?

human: A A K J L C D Y T A A L M N

organism #1:A A K T L C E Y T A A J M N

organism #2:A A K J L C D Y J A A J M N

7. Would the organism you selected probably be a mammal or a reptile? Why?

8. Besides comparing biochemical evidence (amino acids), what other evidence do scientists have that evolution has occurred?

Fossils, biogeography, homologous structures, vestigial


Living things produce more offspring than will survive there is variation among the offspring

Look at the diagram at the right to answer the next few questions.

9. What is this diagram called?

  • Family tree

  • Cladogram

  • Phylogenetic tree

  • Both B and C

    10. Which two animals are more closely related?

  • Gibbon & orangutan

  • Gibbon & human

  • Chimpanzee & bonobo

  • Bonobo & human

    11. What led you to believe that the two animals you chose in #5 were more closely related?

They are closer together on the cladogram and share the same most recent ancestor.


Types of natural selection patterns rates of evolution

Types of Natural Selection, Patterns & Rates of Evolution

Biology 102Y

SB5b. Explain the history of life in terms of biodiversity, ancestry, and the rates of evolution.

SB5e. Recognize the role of evolution to biological resistance (pesticide and antibiotic resistance).


Types of natural selection

Types of Natural Selection

  • Stabilizing- average phenotypes are favored

    • Plants- short plants can’t compete for sunlight so they die, tall plants can’t withstand winds so they die, this leaves medium height trees

  • Directional- population moves from one extreme to the other

  • Disruptive/Diversifying- extreme phenotypes are favored

    • Light and dark are favored so they survive, medium stick out and get eaten


Living things produce more offspring than will survive there is variation among the offspring

In peppered moths there are two major phenotypes- light color and dark color

  • Before the Industrial Revolution:

  • Light moths blend in, dark moths stick out, dark get eaten

  • Dark phenotype gets eaten so not very common so the dark allele is not frequent

  • After the Industrial Revolution:

  • Dark moths blend in, light moths stick out, light get eaten

  • Light phenotype gets eaten so not very common so the light allele becomes less frequent

During the Industrial Revolution large amounts of air pollution killed the lichens on the tree, exposing the dark bark underneath.

Before the Industrial Revolution light colored moths had a better chance of survival. After the Industrial Revolution dark colored moths had a better chance of survival. This change in the moth population over time is EVOLUTION of a POPULATION.


Living things produce more offspring than will survive there is variation among the offspring

Notice the peak of the blue line is over the light phenotype

Notice the peak of the red line is over the dark phenotype

This shows that the population evolved from light being more common before Industrial revolution to dark after.

This type of natural selection is called…

Change in Moth Phenotype from 1800’s-1900’s

Moth Pop-ulation

  • Directional selection

  • Diversifying selection

  • Stabilizing selection

Phenotypes of Moths


Patterns of evolution

Patterns of Evolution

1. Adaptive Radiation

  • Many species evolve from a common ancestor

  • Occurs as a result of geographic isolation- organisms are separated by a canyon or physical barrier and can’t breed together- creates new species

  • Also called divergent evolution

  • EX: one population that ended up being separated by Grand Canyon, developed into two new species- kaibab squirrel & abert squirrel

  • EX: Darwin’s finches


Patterns of evolution1

Patterns of Evolution

2. Coevolution

  • Species evolve in close relationships with other species

  • Mutualism

    • Ex: flowers & their insect pollinators

  • Predator-prey

    • Ex: cheetahs & antelope

    • Ex: plant chemical defenses & insects


Patterns of evolution2

Patterns of Evolution

3. Convergent evolution

  • Unrelated species evolve similar traits even though they live in different parts of the world.

  • Similarity in environment has led to evolution of similar traits.

  • EX: Madagascar aye-aye and New Guinea striped opossum both have elongated middle fingers. Live separately but have same structure


Rates of evolution two types

Rates of EvolutionTwo Types:

  • Gradualism

    • Small, gradual steps

    • Traits remain unchanged for millions of years

  • Punctuated Equilibrium

    • Abrupt transitions

    • Seen in fossil record

    • Rapid spurts of genetic change caused divergence quickly


What are some current trends in evolution

What are some current trends in evolution?

1. Natural Selection

  • Bacteria are becoming resistant to antibiotics b/c of the misuse of antibiotics. Bacteria are building resistance.

  • Insects are also building resistance to pesticides due to overuse & improper use of the chemicals.

  • Industrial melanism- peppered moths changed due to pollution.

  • Generally, organisms that are more general in their needs survive. A species that requires a specific food source or habitat will be less able to change.

    2. Artificial Selection

  • Genetically modified foods

  • Selective breeding in dogs & plants (crops)

http://www.pbs.org/wgbh/evolution/educators/lessons/lesson6/act1.html


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