genetic changes in a population over time

Question 1

gene

Answer 1

section of DNA carrying the code for a trait

Question 2

allele

Answer 2

alternate form of a gene. arise by mutation

Question 3

genotype

Answer 3

genetic makeup

Question 4

phenotype

Answer 4

observable trait

Question 5

population

Answer 5

group of individuals of the same species in the same geographic location

Question 6

what is natural selection

Answer 6

the process where organisms better adapted to their environment tend to survive and produce more

Question 7

general process of natural selection

Answer 7

1. variation exists in the population’s genotype
2. selection pressure impacts the population
3. som phenotypes have a selective advantage and are more likely to survive
4. those that survive reproduce and pass on the advantage

Question 8

selection pressure

Answer 8

factor that affects allele frequency in a population

Question 9

evolution

Answer 9

change in the genetic composition of populations over time

Question 10

gene flow

Answer 10

the transfer of alleles or genes from one population to another

Question 11

genetic drift

Answer 11

the change in frequency of alleles in a gene pool due to chance events

Question 12

bottleneck effect

Answer 12

occurs when a population size is reduced for at least one generation.
- make species more vulnerable to environmental change due to potential interbreeding

Question 13

founder effect

Answer 13

occurs when a small group of individuals from a larger population move to a new location and establish a new population

Question 14

mutations

Answer 14

changes in DNA, unpredictable and random

Question 15

point mutations

Answer 15

the mutation that adds or removes a single nucleotide from a particular point in the sequence of DNA or RNA

Question 16

substitution mutation

Answer 16

a point mutation in which one nucleotide replaces another type of nucleotide

Question 17

silent mutation

Answer 17

occurs when a substitution results in a new codon that is still coed for the same amino acid

Question 18

missense mutation

Answer 18

substitution mutation that results in a new amino acid

Question 19

nonsense mutation

Answer 19

when a substitution mutation results in the creation of a stop codon

Question 20

frameshift mutation

Answer 20

involves one or two nucleotides either being added or removed from the nucleotide sequence

Question 21

chromosomal mutations

Answer 21

when a mutation involves large sections of chromosomes or a whole chromosome

Question 22

polyloidy

Answer 22

condition in which a normally diploid cell aquires one or more additional sets of chromosomes

Question 23

block mutations

Answer 23

affect large sections of chromosomes, can result in large changes in viable offspring

Question 24

selective breeding

Answer 24

humans selectively develop particular phenotypic traits by choosing which animals or plants. will sexually reproduce and have an offspring

Question 25

steps in selective breeding

Answer 25

1. determine the desired trait
2. interbred parents who show the desired trait
3. select the offspring with the best form of the trait and interbreed these offspring
4. continue this process until the population reliably reproduces the desired trait

Question 26

antigenic drift

Answer 26

viruses can have random mutations that may give them resistance to the target of vaccination, this could lead to vaccine evasion

Question 27

antigenic shift

Answer 27

viruses will sometimes swap their DNA or RNA when they are both infecting the same cell, can allow them to change rapidly and greatly

Question 28

fossils

Answer 28

preserved remains, impressions or traces of an organism found after its death

Question 29

fossilisation

Answer 29

• fossils are most commonly
  found in sedimentary rock
• soft-bodied organisms are
  unlikely to be preserved as
  parts rapidly decay
  -burriel is essential

Question 30

idex fossils

Answer 30

used to define and identify geological periods
- relative dating

Question 31

transitional fossil

Answer 31

found between species and its ancestor

Question 32

carbon dating

Answer 32

works on any living thing, but is limited by the age of a fossil

Question 33

mass extinctions

Answer 33

large-scale extinctions following disruptive changes to the global climate

Question 34

allopatric speciation

Answer 34

occurs when a population becomes divided by a geographical barrier

Question 35

warbler finch

Answer 35

has a slender beak. migrates to an island with only seeds and few insects, it would struggle to find enough food, resulting in selection pressure and adaptations to the local environment over time

Question 36

sympatric speciation

Answer 36

occurs when there is a niche within a population
- new traits are an advantage in this niche, but not an advantage to the entire population
- new species may form

Question 37

howea palms

Answer 37

used as an example of sympatric speciation, as the palms could not have been geographically isolated from each other, being on a secluded island.

Question 38

structural morphology

Answer 38

the study of the physical makeup of external and internal structures
- gives insight into relationships between species

Question 39

homologous features

Answer 39

• features that have fundamental similarities based on common ancestry
  -involve different functions, but the similar structure suggests the organisms shared a common ancestor

Question 40

vestigial structures

Answer 40

some organisms possess structures that have little or no function
remnants of structures that had a function in ancestral species have reduced in size over time and ceased to be used

Question 41

molecular homology

Answer 41

the similarity of patterns in the nucleotide sequences of DNA or the amino acid sequences in polypeptides from different organisms is evidence for a common evolutionary origin

Question 42

determining relatedness using molecules

Answer 42

if two populations become isolated from each other, they will eventually have differences in DNA

the more mutations that accumulate in the DNA sequences between the two species, the more time will have passed since the two species diverged from their common ancestor

Question 43

differences in amino acid sequences

Answer 43

as two species diverge from a common ancestor, they accumulate different mutations in their DNA, this causes these species to accumulate differences in the amino acid sequences of their proteins
- differences in amino acids accumulate more slowly than in DNA

Question 44

phylogenetic trees

Answer 44

way of representing the relatedness of species

Question 45

mamals

Answer 45

• presence of mammary glands to produce milk to feed young.
• have neocortex in the brain, fur or hair and three middle ear bones

Question 46

primates

Answer 46

social animals that typically live in groups

• hands and feet have 5 digits, opposable thumbs/big toes, flat nails
• short nose, large eyes, large brain, relatively long gestation period

Question 47

hominoids

Answer 47

• lack tails
• wide degree of motion in the shoulder joint
  -similar skeletal features
  -similar skulls

Question 48

brian size

Answer 48

• hummans have large brains for their size, even compared to other hominoids

Question 49

limb structure

Answer 49

longer legs are more efficient for bipedalism
arms are shorter, betteer while walking

Question 50

mitochondrial DNA (mtDNA)

Answer 50

only passed on through the maternal line of sexually reproducing organisms

Question 51

country

Answer 51

an area traditionally owners and looked after by an abo language group or community

Question 52

place

Answer 52

mapped out by physical boundaries that abos occupy and are regarded as their own.