Evolution Flashcards
What is evolution?
The gradual change in a species over time
Was Charles Darwin poor?
NOPE
What did Darwin study?
Medicine and Theology
What did he become instead?
A Naturalist
What disease did Darwin contract on his voyage?
Chagas disease (protozoan)
What book did he publish in 1859?
On the Orgin of Species
How many beetles did he observe in Brazilian forest?
68 different ones a day
What idea shaped Darwins thinking?
Hutton and Lyell, who fel the earth was millions of years old (actually 4.6 billion) and the earth has changed over its history to present form
What did Jean - Baptiste Lamarck propose?
That through selective use and disuse of organisms, organisms acquired or lost certain traits during their lifetimes
What was Lamarck’s Giraffe theory?
That the Giraffes need to keep stretching their necks to reach food higher up
What else did Lamarck discover?
Traits in an organisms lifetime can be passed to offspring
Thomas Malthus discovered that reporduuction rate…
is faster than death rate
Thomas Malthus discovered that population growth…
Is an exponential growth
Thomas Malthus discovered that sooner or later…
there will not be enough room to survive
Thomas Malthus discovered that war…
famine and diseases are the only forces to keep population size from outdistancing food supply
What does fossil evidence show?
Living things have been evolving on earth for millions of years
What does fossil evidence show about the geographic distribution?
The genetic distribution of organisms lines up with trhe movement of the earths crusts and that newer forms of fossilized organisms are found in the upper layers of the rock
What are homologous structures?
Structures that have similar form but different functions
What are examples of homologous structures?
Bones of forearm, flipper of whale (front), wing of a bat, and legs of a tuurtl
What are vestigial organs?
Structures which no longer have a function to the organism
What are 6 points in Darwin’s theory?
- Natural Selection
- Malthusian Doctrine
- Competition for limited resources among member in a species
- Struggle for existence
- Survival of the fittest and natural selection
- Species change over time
- Common Descent
- Adaptive radiation
What did Darwin say about Natural Selection?
Inherited variations exist between organisms
What did Darwin say about the Malthusia Doctrine?
Organisms in nature produce more offspring than can survive
What did Darwin say about Survival of the fittest?
Those members of the population with the best natural variations will survive and pass the traits on to their offspring
What did Darwin say about common descent?
Species alive today descended with modifications from past species
What did Darwin say about adaptive radiation?
It occurs when a species or a group of species evolve into many new species to fit a particular niche
What were Darwin’s finches?
Small brown birds
What were his ancestroal finches?
They evolved to adapt to open niches on the various Galapagos Islands
`What individual traits did they have each?
Some had a shorter, fate beak for cracking seeds.
Some had small pointy beaks for opening small seeds
Some had long pointy beaks for getting in creases
What is Divergent evolution?
Where two or more related populations become more and more disimilar
What does divergent evolution result in?
New species
What very important info was Darwin missing in his Theory of Evolution
- What was the source of variation?
2. How these variations passed from generation to generation
What year did scientists combine the men’s concepts?
1910
What are sources of genetic variation?
Mutation
Gene shuffling
Crossing over
Sexual reproduction
What can mutation do?
increase, decrease, or no effect on organism’s fitness
Does reproduction affect the genes frequency?
NAH
What is the founder effect?
The change in gene frequency as a result of the movement of a small group of population
