1 / 35

Charles Darwin British Naturalist 1809 -1882

Charles Darwin British Naturalist 1809 -1882. Ok so he might look a little ancient, but Darwin’s ideas are only about 150 years old.

stacy-holmes
Download Presentation

Charles Darwin British Naturalist 1809 -1882

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Charles DarwinBritish Naturalist1809 -1882 Ok so he might look a little ancient, but Darwin’s ideas are only about 150 years old.

  2. Charles Darwin studied many different plants and animals while traveling on the HMS Beagle. The Galapagos Islands is the most famous stop of the Beagle’s voyage

  3. Darwin is best known for his study of Finches. Darwin’s Finches

  4. What was it that Darwin noticed? • Darwin noticed how the beak of each finch is adapted to the way the bird usually gets food

  5. Artificial Selection(Selective Breeding) • Humans can breed animals to achieve desired characteristics. This is known as artificial selection. • Examples: cows, cattle, pigs, dogs, birds, horses, various plants, etc. Darwin already realized this…

  6. And eventually Darwin proposed this… Natural Selection • The process by which individuals that are better adapted to their environment survive and reproduce more successfully than less well adapted individuals do

  7. Natural Selection

  8. Natural selection is simply the logical result of four features of living systems: • variation - individuals in a population vary from one another • inheritance - parents pass on their traits to their offspring genetically • selection - some variants reproduce more than others • time - successful variations accumulate over many generations

  9. Organisms adapted to a particular environment may become extinct if the environment changes.

  10. Haven’t seen any of these recently have you?...

  11. Variation 5 million years ago • Slight variations (differences) in structure can increase or decrease an organisms chance for survival. 23 million years ago

  12. What Darwin didn’t know… How are traits inherited?

  13. A family tree is a type of diagram used to show your relationship to other members of your family. • Similar “trees” are used to show relationships between species • The fossil record indicates that diversity of species is developed through gradual processes over MANY generations Where are the oldest (original) ancestors located? Where did your traits come from?

  14. Where do traits come from?Sexual and Asexual Reproduction

  15. Asexual Reproduction

  16. Asexual reproduction occurs due to mitosis (cell division)

  17. Asexual Reproduction • Asexual reproduction does not involve sex cells. • Asexual reproduction requires only one parent.

  18. Asexual Reproduction • Asexual reproduction is more common among plants, but a few animals do use asexual reproduction. • Examples: • Strawberries, potatoes, quackgrass, cactus plants, bacteria, some worms, bees, starfish and the whiptail lizard

  19. Benefits of Asexual Reproduction • A single female can repopulate a population • Guarantees reproduction (no dependence on others) • Asexual reproduction produces genetically identical offspring (no new traits), unless mutations occur (random change in genes) • Rapidly increases number of organisms

  20. Problems with Asexual Reproduction • Changing environments (or disease) can cause species to become extinct because they can not adapt (no genetic variation) • Changes can only occur due to mutations

  21. Sexual Reproduction • Traits are determined by a combination of inherited characteristics from two parents

  22. Benefits of Sexual Reproduction • Beneficial properties of two organisms are combined in one individual • Allows for faster adaptation

  23. Problems with Sexual Reproduction • Beneficial traits can be lost due to the dominance of other traits • Reproduction depends on mating (two organisms) • Slower increase in number of organisms

  24. Gregor Mendel • discovered the principles of heredity about 150 years ago • Mendel studied various traits of pea plants • Color, height and shape

  25. Punnett Squares Red: R White: r • Punnett squares are used to organize all the possible combinations of offspring from particular parents Red: RR or Rr White: rr

  26. Punnett Squares Red: R White: r • Phenotype: an organisms appearance • Ex: Red or white • Genotype: the genetic makeup of an organism • Ex: RR, Rr or rr Red: RR or Rr White: rr

  27. Punnett Squares Red: R White: r • Homozygous: two of the same alleles • Ex: RR or rr • Heterozygous: two different alleles • Ex: Rr Red: RR or Rr White: rr

  28. Determining Traits • Dominant traits are represented by capital letters (S) • Recessive traits are represented by lower case letters (s) • In a combination of dominant and recessive traits, the dominant trait will be visible

  29. Determining Traits • Dominant trait: (S) = scarlet flower • Recessive trait: (s) = white flower • Only a genotype of (ss) will produce a white flower

  30. Punnett Squares Parents: TT x tt Tall: T Short: t

  31. R = round r = wrinkled Y = yellow y = green Genotype: inherited genes present Phenotype (what it looks like)

  32. Stop here before you like Punnett Squares as much as this person.

More Related