Theory of Evolution

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Theory of Evolution

• By,

Starla Gordon
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What is Evolution

• Evolution is the theory that modern organisms
  have descended from ancient organisms.

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Charles Robert
Darwin
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Darwin

• Darwin is the man who came up with the Theory of
  Evolution.
• In 1831 he went to different remote islands. The
  trip lasted for 5 years.
• 30 years later he actually published a book on
  his theory of Natural Selection.

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Diversity of Life

• 10 million species of organisms alive are today.
• It is estimated that 99.9 are now extinct.

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How many species have already died out?
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Definitions

• Fitness- the combination of physical traits and
  behavior is what helps organisms survive and
  reproduce in their environment.
• Common descent- if you look back far enough in
  time all species have shared or have common
  ancestors.

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More Definitions

• Adaptation-successful adaptations enable
  organisms to become better suited to their
  environment.
• James Hulton- In 1788 he proposed that rocks,
  mountains, valleys had been changed gradually
  by rain, heat cold.
• Fossils-preserved remains of ancient organisms.

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Definitions Again

• Geological Time Scale-over 100 years ago,
  researchers noticed that certain layers of rock
  often appeared in the same vertical order
  wherever they were found.
• Relative Dating-used to determine the age of
  fossils in different layers of rock.

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Last of The Definitions

• Radioactive decay- the break down into a
  non-radioactive element at a very steady rate.
• Half-life- a half life is the length of time
  required for half the radioactive atoms in a
  sample to decay.

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What are the definitions?

• Relative Dating?
• Radioactive Decay?
• Half-Life?
• Geological Time Scale?
• Fossils?
• James Hutton?
• Adaptations?

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Ideas that shaped
Darwins Theory of
Evolution
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The influence of Geology

• Principle of geology by Lyell
• Older earth, (big idea of the day)
• Long period of time to evolve
• Saw a volcano erupt , helped him believe in
  geological phenomenon.

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Artificial Selection

• The intervention of humans ensures that only
  individuals with the more desirable traits
  produce offspring.

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The Influence of FarmersArtificial Selection

• Plant animal breeders
• Large corn plants vs. small
• Some dairy breeds vs. others
• Inherited variations
• Farmers used variation to their advantage
• Breeding stock, only most best could mate.

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Influence of Malthus

• Thomas Malthus (1766-1834)
• Observed that babies were born faster than people
  were dying.
• Population Controls

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What were the ideas that shaped Darwin's theory
of Evolution?
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Malthusian Doctrine

• Famine

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Disease
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War
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What is the Malthusian Doctrine?
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Overcrowd

• Mature maple tree could produce thousands of
  offspring.
• Even if one survived in the same spot it would
  overcrowd.
• Mussels millions of eggs? alligators? snakes?
  turtles? only certain offspring survive.

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Evolution by Natural selection

• Wild animals show similar tendencies like what
  domestic animals have.
• Deer- competition amongst males to be a suitor.
• Taller plants will receive sunshine.
• Plants that root deeply will get water.
• Animals competition for food- bird nests

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Survival of The Fittest

• Individuals whose characteristics are well suited
  to their environment survive.
• Individuals whose characteristics are not well
  suited to their environment either die or leave
  fewer offspring.
• Rattlesnakes with no rattles

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Peppered Moths

• Beginning in the 19th century in England
• Peppered moth spend most of their time resting on
  the bark of oak tree trunks. Most of the oak
  trees in England were light brown, speckled with
  green.
• Most of the peppered moths at that time were
  light brown too.
• Some dark ones around, but few.

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Peppered Moths

• Pollution from Industrial Revolution stained
  London trees dark brown.
• Suddenly scientists noticed the population of
  dark moths increased, and the light moths
  population decreased.
• WHY? Next slide

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Peppered Moths

• Birds were the moths major predator. Birds can
  not see ones that blend in with tree trunks.
  Camouflage
• The dark moths reproduced.
• Kettlewell- scientist who studied peppered moths.

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Genetics of Evolutionary Theory

• Darwin did not understand how traits were passed
  on to each generation.

• Today we define fitness, adaptation, species, and
  process of evolutionary change in genetic terms.

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Genetics

• Mendel- working on genetic theory same time as
  Darwin.
• Genes- are the carriers of inheritable
  characteristics, are also source of random
  variation.
• Meiosis- chromosomes are copied shuffled like
  cards dealt out to gametes.

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Genetics continued

• No organism can change its DNA, because it wants
  to.
• Some physical traits passed on by DNA are
  widows peak
• tongue shape
• first finger
• ear

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Whole Organism

• In evolution the struggle for existence depends
  on the entire organism not individual genes.
• Brown eyes for example may or may not secure
  existence of organism- Entire combination

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Population

• Populations- a collection of individuals of the
  same species in a given area whose members can
  breed with one another.
• Example all fishes of a certain species in a
  single pond can be one population. Individuals
  in another pond would be a different population.

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Gene Pool

• Gene Pool-group of genes in that population. Each
  gene contains a number of alleles.
• Alleles-certain gene at a given point on a
  chromosome- for each trait-including for
  recessive trait.

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Bla Bla

• Relative Frequency- the number of times an allele
  occurs in the gene pool compared with the numbers
  of times other allele for the same gene occurs.
• Evolution is any change in the relative frequency
  of alleles in the gene pool of a population
• -eyes-still no red or pink?

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The End