Transcript Darwin and Evolution

Developing a Theory
of Evolution
Evolution
 The
processes that have changed life on
earth from it’s earliest forms to the
diverse forms found today.
A
change in the genes!!!!!!
What Influenced Darwin’s Theory?
Jean Baptiste Lamarck (1744-1829)
1st to recognize living things change over time
 made 3 incorrect assumptions:

1) DESIRE TO CHANGE
2) “Use it or Lose it”
3) Aquired traits can be inherited
Charles Lyell
(1797-1875)

A geographer- studied the forces that change the
surface of the Earth

Wrote famous book “Principles of Geology”

Showed that the Earth was VERY old and had
changed over time

Convinced Darwin Earth was older than most
believed gave the time needed for Darwin’s
Theory of evolution to occur
The Influence of Farmers &
Artificial Selection

Darwin spoke to lots of plant and animal breeders,
noticed variation occurred naturally
Farmers choose
to only breed animals
/crops with
DESIRABLE VARIATIONS


Therefore, farmers were artificially selecting
(mates/traits) so that only the best traits were
passed on via reproduction
Thomas Malthus
(1766-1834)


Observed more babies being born than people
dying… population should be growing out of control
Many species make lots of eggs/sperm BUT ONLY A
FEW OFFSPRING survive!
Ex) Salmon for 4000 eggs 1survives
]Ex) Humans
150,000 sperm only 1 fertilizes egg
Charles Darwin (1809-1882)
Darwin
 Set
sail on the H.M.S. Beagle for
5 years! (1831-1836) Surveyed
the South seas
 Was most influenced by South
America and ESPECIALLY the
Galapagos Islands!
 Collected plants and animals &
wrote detailed observations
 In 1859 Wrote “Origin of
Species” to explain his Theory of
Evolution…
Darwin’s Theory of Evolution
4 main points:
1. Over population/reproduction
 not all offspring actually survive
2. Variation Exists WITHIN species
 Not all offspring are exactly the same
3. Less “Fit” organisms die
4. More “Fit” organisms survive