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Flashcards in Exam 1 Deck (41)
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1

Mutations in ______ cells are more important

sex
they are passed on to next generations.

2

Point mutation-

change in one nucleotide

3

Substitution point mutations can be ________ (silent) or ________ (meaningful)

synonymous
non-synonymous

4

Silent mutation-

codon from this mutation specifies the same amino acid as the non-mutated codon. No protein change.

5

Codon-

triplet sequence of nucleotides that specifies a particular amino acid

6

Non-synonymous (meaningful) point mutation-

missense, different amino acid, different protein.

7

Large sections of chromosomal mutations-

deletion, duplication, inversion, insertion, translocation.

8

Gene position may or may not be important in its __________

expression

9

Trisomy 21 is due to _________. Leads to ___________

-nondisjunction, extra T21 chromosome
-Down Syndrome

10

Fusion of a chromosome might be a significant effect in __________

speciation

11

Estimated number of protein coding genes in humans

25,000

12

Gross generalization: mutation rate per generation is:

10^-5 or 10^-6

13

mutation rate (_______) is too low to be main force in evolution. Between _____% of us carry a genetic mutation compared to our parents. Although mutation is too low to be main force of evolution, it is the only source of ___________

-.025 to .25
-5-44%
-new genes in a species.

14

Mutations increase genetic variability in a _________ and between __________

-population
-populations

15

Gene flow-

movement of alleles from one population to another due to mating between populations.

16

Gene flow inhibits speciation because ____________________

two populations blend their traits and they are now more similar and less likely to genetically diverge from each other.

17

Genetic drift-

random change in allele frequencies

18

The smaller the population, the more chance of significant ________

mutations

19

Two inferences we can make about genetic drift:

1. All populations evolve every generation by genetic drift
2. magnitude of evolution by genetic drift is greater in a smaller population than a larger population

20

The ultimate result of genetic drift is ___________, and all other alleles of the gene have been _______________

-fixation of an allele
-eliminated from the population

21

Bottleneck and Founder effects-

reduction in genetic variability by chance due to reduction in population size (bottleneck) or establishment of a new, founder population.

22

Natural selection-

differences among individuals in reproductive success

23

The unit of natural selection is _________; the unit of evolution is ___________

-the individual organism
-the population (or species)

24

-Adaptation- result of _________
-Individuals are subject to natural selection, whereas populations (or species) _______

-natural selection
-adapt

25

-Adaptation occurs only if differences among individuals in reproductive success have ____________

some inheritable basis.

26

Fundamental Theory of Natural Selection-

opportunity for natural selection is directly related to genetic variability in a population (or species)

27

There must be ____________________ for there to be natural selection.

genetic differences among individuals in a population (or species), and correspondingly phenotypic differences,

28

Natural selection “acts” directly on __________, and indirectly on ____________

-phenotypic variability
-genetic variability

29

Natural selection –

differential reproductive success among individuals in a population (or species).

30

Three “types” of natural selection

stabilizing selection, directional selection, and diversifying selection