BIOL Evolution

What is evolution?

What is evolution?

A change in the allele frequencies of a population over time.

What was the state of biological sciences like before Darwin's ideas?

Perfect creation, young earth, unchanging earth, people as the best and above nature.

Why do we still care about Lamarck's ideas?

First to propose the idea of evolution.

What did people think about the age of the earth and how much it had changed?

Young earth, unchanging earth.

What is the mechanism of evolution?

Natural Selection

What is the pattern of evolution?

Common Descent (Descent with Modification)

What are the requirements for evolution by natural selection?

Heritable genetic variation, differential reproduction

What are the four principles of natural selection?

Individuals vary in their traits, differential reproduction with respect to that trait, trait is heritable, the trait with the advantage becomes more common in the population

What is variation?

Genetic differences in the population

What is inheritance?

The traits that are passed down

What is differential survival and reproduction?

The process of survival and reproduction of individuals with more favorable traits in a population

What is population change?

The size of the population changing, increasing and decreasing over time

How does natural selection lead to adaptation?

As more advantageous traits become more common, the population becomes adapted to its environment

Can selection happen without variation?

No, because there needs to be variation for selection to occur

Can evolution happen without heritability?

No, because there is no overall change if alleles cannot be passed down

Give an example of a trait in humans that shows variation but isn't heritable.

Hair color - if dyed, it won't be passed down

What is stabilizing selection?

Selection for mean trait value(s) and against extreme trait value(s). Decreases trait diversity.

What is directional selection?

Selection for one extreme trait value(s) and against the other extreme trait value(s). Does not change trait diversity.

What is diversifying selection?

Selection for both extreme trait value(s) and against the mean trait value(s). Increases trait diversity.

What is the Modern Synthesis?

Combination of Darwin's ideas about evolution with Mendel's ideas of genetics.

What is DNA?

Molecule that stores information.

What does DNA stand for?

Deoxyribonucleic acid.

What are the four bases of DNA?

Adenine, Guanine, Thymine, Cytosine.

What are alternative versions of the same gene called?

Alleles.

What is the functional unit of DNA called?

Gene.

What does a codon code for?

One amino acid.

What do some genes code for?

Proteins.

What do other genes regulate?

Expression of other genes.

What are chromosomes?

Condensed/coiled strands of DNA stored in the nucleus.

How many copies of each gene does a diploid organism have?

What is an organism's genetic material called?

Genome.

What determines an organism's phenotype?

Genes and environment.

What are the two main types of mutations?

Germline and somatic.

Do somatic mutations contribute to heritable genetic variation in populations?

No.