biology chapter 16 Flashcards Preview

PCAT > biology chapter 16 > Flashcards

Flashcards in biology chapter 16 Deck (28):
1

evolution

the change in the genetic makeup of a population with time

2

fossils

are the most direct evidence of evolutionary change

3

actual remains

including teeth, bones, etc,. Found in rock, tar pits, ice and amber (the fossil resin of trees)

4

petrification

is the process in which minerals replace the cells of an organism

5

imprints

are impressions left by an organism, i.e. footprints

6

molds

form in hollow spaces of rocks, as the organisms within decays

7

casts

are formed by minerals deposited in molds

8

homologous structures

have the same basic anatomical features and evolutionary origins. They demonstrate similar evolutionary patters with late divergence of form due to differences in exposure to evolutionary forces

9

analogous structure

have similar functions but may have different evolutionary origins and entirely different patterns of development. Analogous organs demonstrate superficial resemblance which cannot be used as a basis for classification

10

vestigial structures

are structures that appear to be useless but apparently had some ancestral function

11

Darwin's theory of Natural Selection

1. overpopulation 2. variations 3. competition (struggle for survival) 4. natural selection 5. inheritence of the variations 6. evolution of new species

12

population

includes all members of a particular species inhabiting a given location

13

gene pool

of a population is the sum total of all the alleles for any given trait in the population

14

gene frequency

is the decimal fraction representing the presnece of an allele for all memebers of a population that have this particular gene locus.

15

p

is used for the frequency of the dominant allele of a particular gene locus

16

q

represents the frequency of the recessive allele

17

Hardy-Weinberg Principles

1. the population is very large 2. there are no mutations that affect the gene pool 3. mating between individuals in the population is random 4. there is no net migration of individuals into or out of the population 5. the genes in the population are all equally successful at reproducing

18

Hardy-Weinberg equation

p2 + 2pq + q2 = 1

19

agents of microevolutionary change

natural selection, mutation, assortive mating, genetic drift, and gene flow

20

natural selection

genotypes with favorable variations are selected through natural selection, and the frequency of favorable genes increases within the gene pool. Genotypes with low adaptive values tend to disappear

21

mutations

gene mutations change allele frequencies in a population, shifting gene equilibria

22

assortive mating

if mates are not randomly chosen, but rather selected according to criteria such as phenotype and proximity, the relative genotype ratios will be affected, and will depart from the predictions of the Hardy-Weinberg equilibrium. On the average, the allele frequencies in the gene pool remain unchanged

23

genetic drift

refers to changes in the composition of the gene pool due to chance. Genetic drift tends to be more pronounced in small populations, where it is sometimes called the founder effect

24

gene flow

migration of individuals between populations will result in a loss or gain of genes, and thus change the composition of a population's gene pool

25

speciation

is the evolution of new species, which are groups of individuals who can interbreed freely with each other, but not with members of other species.

26

deme

is a small local population

27

adaptive radiation

is the emergence of a number of lineages from a single ancestral species

28

heterotrophs

depend upon outside sources for food