Evolution Flashcards
Evidence of Evolution: Same structure, different function; e.g. wing of bat, flipper of whale, arm of human.
Homologous structures
Evidence of Evolution: Structures which once had a function, but no longer do; e.g. wisdom teeth
Vestigial Structures
Evidence of Evolution: Provide a visual record of how organisms change over time.
Fossils
Evidence of Evolution: Similarities in the early development of vertebrate embryos; e.g. early embryonic development of humans and monkeys
Embryology
Evidence of Evolution: Unrelated organisms, similar physical structures; e.g. wing of bat, wing of bird, wing of butterfly.
Analogous Structures
Evidence of Evolution: # of differences in amino acid sequence; e.g. sequence of human hemoglobin identical to chimpanzee while less closely related primates have greater differences.
Molecular biology
Change in allele frequency of a species over time
Evolution
Certain animals with certain traits live to reproduce and others don’t, those traits become more common
Natural Selection
Can a theory be modified? When?
A theory can be modified when there are new discoveries that aid in understanding.
When is a theory born?
When a substantial # of hypotheses point ot the same conclusion
What is the Hardy-Weinberg Principle used for?
to predict genotype frequencies in a population
Write down the Hardy-Weinberg Principle and what each part stands for:
p^2 + 2pq + q^2
p^2 = frequency of homozygous dominant genotype
2pq = frequency of heterozygous genotype
q^2 = frequency of homozygous recessive genotype
Where did homo sapiens originate?
The Horn of Africa
Describe the relation between solar intensity and skin color - why does this happen?
The more intense the sun’s rays the darker the skin; vice versa - bc of melanin forming a protective barrier to prevent UV rays from causing thymine dimers (T-T vs. T-A)
What can thymine dimers lead to?
Skin Cancer
Melanin: Darker skinned people have more ____________. Fairer skinned people have more ____________.
- Eumelanin
- Pheomelanin
In areas with greater solar intensity, what skin colors are selected for/against - why? What are the effects?
Darker skin is selected for - higher levels of melanin protect the folic acid in the bloodstream
Lighter skin is selected against - lower levels of melanin don’t protect the folic acid from being broken down
Effects of low folic acid?
Low fertility and birth defects
In areas with less solar intensity, what skin colors are selected for/against - why? What are the effects?
Lighter skin is selected for - skin has adapted to be more efficient to produce vitamin D with less sun
Darker skin is selected against - skin needs more sun to produce vitamin D
