Developing a Developing a Theory of Theory of EvolutionEvolution

EvolutionEvolution

The processesprocesses that have changed life on earth from it’s earliest formsearliest forms to the diverse diverse forms found today.

A changechange in the genes!!!!!!genes!!!!!!

What Influenced Darwin’s What Influenced Darwin’s Theory? Theory?

Jean Baptiste LamarckJean Baptiste Lamarck (1744-1829) 1st to recognize living things change over

time made 3 incorrect assumptions:

1) DESIRE TO CHANGE1) DESIRE TO CHANGE

2) “Use it or Lose it”2) “Use it or Lose it”

3) Aquired traits can be inherited3) Aquired traits can be inherited

Charles Lyell Charles Lyell (1797-1875)(1797-1875)

A geographer- 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 DarwinDarwin 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)Charles Darwin (1809-1882)

DarwinDarwinSet sail on the H.M.S. BeagleH.M.S. Beagle

for 5 years! (1831-1836) Surveyed the South seas

Was most influenced by Was most influenced by South America and South America and ESPECIALLY the Galapagos ESPECIALLY the Galapagos Islands!Islands!

Collected plants and animals & wrote detailed observations

In 1859 Wrote “Origin of Species” to explain his Theory of Evolution…

Darwin’s Theory of Darwin’s Theory of EvolutionEvolution4 main points:4 main points:1.1.Over population/reproduction Over population/reproduction

not all offspring actually survivenot all offspring actually survive

2.2.Variation Exists WITHIN speciesVariation Exists WITHIN speciesNot all offspring are exactly the Not all offspring are exactly the

samesame

3. Less “Fit” organisms die3. Less “Fit” organisms die

4. More “Fit” organisms survive4. More “Fit” organisms survive