Darwin and Evolution - PowerPoint PPT Presentation

Loading...

PPT – Darwin and Evolution PowerPoint presentation | free to download - id: 708ac6-MjQ5Y



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Darwin and Evolution

Description:

Darwin and Evolution Evidence Adaptation Speciation Darwin s Voyage H.M.S. Beagle (1831) as the ship s naturalist collected plant and animal specimens ... – PowerPoint PPT presentation

Number of Views:46
Avg rating:3.0/5.0
Slides: 21
Provided by: Mand136
Learn more at: http://mysite.cherokee.k12.ga.us
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Darwin and Evolution


1
Darwin and Evolution
  • Evidence
  • Adaptation
  • Speciation

2
Darwins Voyage
  • H.M.S. Beagle (1831) as the ships naturalist
  • collected plant and animal specimens
  • collected fossils
  • some resembled organisms still alive
  • some were completely unknown

3
Darwins Voyage
  • Galapagos Islands (west of South America)
  • found giant land tortoises, marine iguanas and
    finches with differently shaped beaks

4
Darwins Voyage
  • Returned to England in 1836
  • discovered that the organisms found on the
    Galapagos were found nowhere else
  • BUT, each species looked like similar species
    found on the mainland
  • 1859 he published On the Origin of Species
  • Proposed the idea of natural selection
  • struggle for existence
  • survival of the fittest live to reproduce

5
Ideas That Influenced Darwin
  • James Hutton proposed that Earth is shaped by
    geological forces that took place over extremely
    long periods of time
  • Charles Lyell explained that processes
    occurring now have shaped Earths geological
    features over long periods of time

6
Ideas That Influenced Darwin
  • Jean-Baptiste Lamark proposed that by selective
    use or disuse of organs, organisms acquired or
    lost certain traits during their lifetime
  • These traits could be passed on to their
    offspring
  • Alfred Wallace wrote to Darwin, speculated
    about evolution by natural selection based on his
    studies of plants and animals

7
Darwins Theory
  • Variations exist in a population and are
    inherited
  • In nature, there is a tendency toward
    overproduction
  • Species compete for limited resources
  • Each individual has advantages and disadvantages

8
Darwins Theory
  • Individuals best suited to the environment
    survive and reproduce those not as well suited
    die or have fewer offspring
  • Species change over time new species appear and
    others disappear
  • Descent with modification
  • Common descent

9
Evidence for Evolution
  • Anatomy
  • Embryology
  • Biochemistry
  • Genetics

10
Anatomy
  • comparative anatomy study of structures of
    different organisms
  • vestigial organs structures that have no
    function in the living organism (appendix)
  • homologous parts similar body parts

11
Embryology and Biochemistry
  • comparative embryology study of developing
    organisms
  • embryos start out very similar, but as they
    develop, they become distinct
  • comparative biochemistry studies of organisms
    on a biochemical level (proteins, DNA)

12
Genetics
  • production of new alleles and genetic
    recombination
  • mutations
  • selective breeding
  • DNA of humans and chimps is 99 identical

13
Adaptation
  • Structural
  • Physiological
  • Behavioral

14
What is an adaptation?
  • Any trait that aids the chances of survival and
    reproduction of organisms
  • Variations vs. Adaptations
  • Adaptations are products of evolution by natural
    selection (always good)
  • Variations are the raw materials upon which
    natural selection acts (can be good or bad)

15
Complex adaptations
  • e.g. the eye
  • Does not arise overnight
  • Occurs over many, many generations
  • Does not invent, but modifies what already exists

16
Types of adaptations
  • Structural adaptations adaptations involving
    structure or anatomy (woodpeckers beak,
    anteaters snout)
  • Physiological adaptations adaptations with a
    chemical basis that is associated with an
    organisms function (spiders web, snake venom)
  • Behavioral adaptations results from the
    response of an organism to its environment
    (birds migrating, plants growing to light)

17
Human Evolution
  • Homo habilis
  • Homo erectus
  • Homo sapien

18
Primate adaptations
  • Humans are primates (so are monkeys and apes)
  • Problem-solving ability
  • Flexible shoulders and forelimbs that can be
    rotated
  • Opposable thumb

19
African origins
  • Australopithecines southern ape
  • Lucy 3.5 million years old
  • 3-4 tall and about 66 pounds
  • If she were alive today, she would not be
    considered human

20
Origin of Humans
  • Hominids modern humans
  • Handy man (Homo habilis) 1.8 million yrs ago
    made tools
  • Upright man (Homo erectus) 1 million yrs ago
    learned to make and use fire
  • Modern man (Homo sapien)
  • Neanderthals short, powerfully built
  • Cro-magnons fully modern height, skull
    structure, skeleton, teeth and brain size
About PowerShow.com