What is evolution? i.e. the gene pool changes, individuals do not evolve

Transcription

1 What is evolution? Involves changes in populations, species, or groups of species Process by which the frequency of heritable traits (alleles) in a population changes from one generation to the next i.e. the gene pool changes, individuals do not evolve

2 Jean-Baptiste Lamarck Theory included two main ideas: 1. Use and disuse body parts can develop with increased use, unused parts weaken Turned out to be correct 2. Inheritance of acquired traits- body features acquired during the lifetime of an organism could be passed onto offspring Turned out to be incorrect only changes in genetic material can be passed on

3 This theory is incorrect

4 Fun Facts About Lamarck (to make you wonder about him)

5 Charles Darwin Published his ideas 50 years after Lamarck in The Origin of Species Theory- Natural selection or survival of the fittest was the driving force of evolution

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7 Charles Darwin ( ) Sailed around the world on the HMS Beagle

8 Random Fact: Darwin almost didn t go to go on that adventure because the ship s captain thought his nose looked weird

9 Darwin s book The Origin of Species was published about 20 years after he first wrote it (he thought church people would be mad at him) He was a Christian after all

10 Natural Selection Differences in survival and reproduction among individuals in a population i.e. some individuals possess alleles that generate traits that enable them to cope more successfully in their environment than other individuals

11 Natural Selection More successful individuals produce more offspring Superior inherited traits are adaptations to the environment and increase an individuals fitness Fitness relative ability to survive and produce offspring

12 The traits that help an organism survive in a particular environment are selected in natural selection, and those organisms can reproduce Natural Selection

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16 Darwin used the following arguments for Natural Selection: Populations have an enormous reproductive potential Population size remains stable Resources are limited Individuals compete for survival There is variation among individuals in a population Most variation is heritable Only the most fit individuals survive Evolution occurs as favorable traits accumulate in a population

17 Variation is key! What are the sources of variation? Mutations Sexual Reproduction Crossing-over Independent assortment of homologous chromosomes Random joining of gametes

18 Random Darwin Facts: Darwin made a Pro/ Con list before getting married. The phrase A companion better than a dog anyway was in the benefit column He married his first cousin (it happens sometimes I guess ) and had 10 kids (7 grew to become adults) He liked eating exotic animals, like owls, armadillos, ostrich, and puma. A mountain was named after him for his 25 th birthday because why not?

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21 This is kind of true though

22 Natural Selection Examples

23 Diurnal worms (birds eat them) Nocturnal worms (birds don t get them) Worms eat at different times of the day (some at night, some in day) Nocturnal worms won t be eaten by birds 500 babies are born, only 100 become adults Nocturnal worms survive to make more babies There will eventually be more nocturnal than diurnal worms

24 Thin coats Thick coats (and maybe medium) There are three different coat types (thick, medium, and thin) It s good to have thick fur when it s cold outside About 2 cubs are born but only one survives Bears with thicker fur will probably survive There will be more bears with thick fur surviving

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26 Last steps: Use the links in the next two slides to help you find the video and reading

27 Amoeba Sisters Video 7VM9YxmULuo

28 CK : Darwin and the Theory of Evolution Reading Link: Biology/section/10.1/ Use this link to help you find the reading so you can answer the reading guide questions