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BIO UNIT 3/4 > evolution > Flashcards

evolution Flashcards

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1
Q

what is natural selection?

A

the process of life forms having traits that batter enable them to adapt to specific environmental pressures (change in climate, predators, food) will tend to survive and produce larger amounts of offspring.

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2
Q

difference between microevolution and macro evolution

A

mircroevolution is changes of allele frequencies within a species/population over a short period of time e.g bacteria

macroevolution are major evolutionary change regarding whole taxanomic groups over longer periods of time through accumulation of mircroevolution e.g horses

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3
Q

what is evolution

A

is changes in the allele frequency of a population over successive generations

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4
Q

how does variation occur?

A

through mutation then enhanced through sexual reproduction

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5
Q

how does natural selection lead to evolution

A
  1. variation in a population
  2. more individuals produced than an be supported leadin to struggle for survival
  3. individuals with favourable characteristics outcompeting individuals lacking those characteristics
  4. favoured individuals surviving and producing offspring or more than others
  5. favourable allele passed on leading to increase in favoured allele in gene pool
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6
Q

explain what selection pressures are and examples of them

A

any feature og the environemtn which increases/decreases the fitness of a particular phenotype in a population

  • resource availability =food,shelter mates
  • environmental conditions- temp,weather, geographical location

biological factor- diseases and predators

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7
Q

pappered moths are an example of what

A

industrial melanism

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8
Q

define allopatric speciation

A

occurs when two or more popuations are separated due to geographical barriers and are prevented from breeding

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9
Q

what is speciation

A

theevolutionary process that leads to the formation of one or more new species from one species over time

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10
Q

what is gene flow and why is it important?

A

is the movement of gnes from one population to another through interbreeding

  • introducing new genes into a population
  • makes populations more genetically similar
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11
Q

examples of phycial geographical barriers

A

lakes river, mountains, valleyes, roads, deserts

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12
Q

list and breifly describe the process of speciation

A
  1. variation- all population carrying a degree of variation between individuals both pheno and genotypes
  2. isolation- geographical barriers separating population and due to different selective pressures natural selection favours differnt characteristicsc in each sub-population there fore genepools changing. also due to mutations no same mutation can occur on each

steps of evolution here

  1. reproductive isolation - 2 populations accumulate enough genetic differences that they no longer can interbreed to create fertile offspring (= new species)
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13
Q

difference between speciation and evolution

A
  • different selection pressures in each population
  • each population evolves in isolation to eachother
  • gene flow ceases
  • eventually gene pools have accumulated many differnces so that the species can no longer be the same species.
  • speciation is a process of evolution

evolution is a process that occurs over successive generations and in microevolution and macroevolution

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14
Q

explain how an advantageous allele can rise and then spread through a population

A

mutations
- through the process of mutation
- this causing a change in DNA which results in a new allele
- caused by mutagen or problem in DNA replication

natural selection
- through the process of natural selection
- there is genetic variation in the population
- individuals with the advantageous allele have higher fitness
- the individuals therefore having more offspring than those organismins with put the favourable trait.
- the offspring inherit the advantageous allele
- the frequency of the advantageous trait will therefore be slightly higher in the next generation
- therefore this allele having a higher frequency over many generations

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15
Q

list 5 ways in which genetic change occurs

A

mutation, migration, natural selection, non-random mating, genetic drift

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16
Q

what are gene pools

A

the sum of the alleles in a given population

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17
Q

describe random genetic drift

A

random genetic drift- a mechanism of evolution in whiich allele frequencies of a populationchange over generations due to chance events (death of indiv) not selection

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18
Q

describe random genetic drift

A

random genetic drift- a mechanism of evolution in whiich allele frequencies of a populationchange over generations due to chance events (death of indiv) not selection

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19
Q

describe the founder effect (genetic drift)

A

a small group of idividuals split off to start a new population
- allele in founder population dont always reflect original population
- once population has increased the genepool is representative of the founder population not the originla population

EXAMPLE: tasmanian tiger separated from mainland aus

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20
Q

describe the bottle neck effect (genetic drift)

A

a sudden durastic reduction in population size ( drought flood, fire, hunt)
surviving indiv constitutes a random genetic sample of the original population.
- population numbers may recover but gene pool will reain small therfore more suseptable to changes in environment and have an increased risk in extinction

EXAMPLE: cheetahs are all practially identical because of this.

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21
Q

list the types of fossils

A

trace= footprint, trail, burrow
mould= impression left by organism
cast = mould filled with mineral rock
true form= shells, teeth, bones

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22
Q

explain the 5 ways fossils provide evidence for the theory of evolution

A
  1. changes over time
    - size= getting larger to travel further
    - foot structure = more robust to reduce injury
    - tooth structure = more robust due to change in diet
  2. organisms becoming more complex over time = protist, invertebrate, vertebates
  3. the variety of fossil increases in upper more recent of rock
  4. no fossil records exist of any modern living plants or animals
    - this suggests that organisms are found as fossils either became exinct or evolved into species currently living
  5. missing links - the common ancestors
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23
Q

what are vesitigail organs and how does it provide evidence for evolution

A

theya re structures that have been reduced in size or has lost its function over the course of evolution

and shows evidence of relationships amoung organisms(evolved from organisms where structures had a function)

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24
Q

how does studies of comparative embryology studies provide evidence for evolution?

A

comparative embryology shows characteristics that vertebrate embryos all share. for example pharyngeal slits, post anal tail, same level of brain development, two chambered heart.

showing that these traits had a function in an ancestor with the organisms but not present i the adults. suggesting they all share a common acestor.

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25
Q

how do homologous structures provide evidence for evolution?

A

evolution suggests that species coming from a common ancestor shoul share homologous charatcers or derived from the same structure. for example the pentadactyle limb is a structure that whales, humans, bats and elephants all have they all serve a different function by have similar structure.

this suggesting that they all has a common ancestor with that structure.

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26
Q

what is the difference between analogous and homologous structures

A

Homologous structures provide evidence for common ancestry, while analogous structures show that similar selective pressures can produce similar adaptations (beneficial features).

27
Q

what are analogous structures and how do they provide evidence for evolution

A

the process where by organisims not closely related and independently evolved similar traits as a resultl og having to adapt to similar environments or ecological niches. having different structure same funtion fro example wings of bats, birds and insects

28
Q

describe the process of dna hybridisation

A
  1. 2 species dna extracted cut ito short fragments then denatured leaving single stranded copies.
  2. DNA are then cooled to allow annealing (more similar = moree bonds)
  3. strands are then reheated to the denature. the heat at which is used to denature the dna helps decide how closely related they are. more heat= more connections made.
29
Q

describe mitochondrial dna and its evidence for evolution

A

Mitochondrial DNA (mtDNA) is inherited only from the mother. Every few generations, a random mutation creeps into this familial signature. So comparison of two samples of mtDNA will show degrees of kinship and ancestral origin.

30
Q

how does ribosomal rna provide evidence for evolution

A

its inhereited from mother and is highly conserved therefore more similar rRNA the more closely related they are.

31
Q

how do protein sequences provide evidence for evolution

A

greater differences in sequences= less closely related.

Cytochrome-c ( electron transport stage of cellular respiration) is a protein used as it has a slow rate of mutation small only has about 100AA

32
Q

Define artificial selection and and the negitive impacts

A

refers to the selection by humans of animals or plants with desirable phenotypes for breeding to produce offspring with desirable characteristics.

causes changes in allel frequency in gene pool resulting in decreased biodiversity ad smaller gene pool (inbreeding depression)

inbreeding depression is the reduced biological fitness in a given population as a result of inbreeding r breeding of related individuals

33
Q

list the desirabel traits in artifical selection

A
  1. resistant to disease
  2. greater product quality
  3. increase yield
  4. tolerance to environmental conditions
  5. faster growth rate
34
Q

describe the process of artificial selection

A
  1. identify desireable traits
  2. choose parents with these traits then crossbreed them to create offspring with these traits
  3. offspring are evaluated and those with the most desireabel traits are selected as parents for th enext generation.
  4. this process is repeated for several generations till desired trait is consistantly present in population
35
Q

describe inbreeding depression and outbreeding depression

A

inbreeding is the reduction of fitness due to the breeding of closely related individuals

outbreeding is the reduction of fitness due to the breeding of 2 genetically differnt idividuals

36
Q

what is extinction

A

the process of death of all the membes of a population or species and may result in genes being perminatly lost in the gene pool

37
Q

how does biodiversity effect evolution

A

high biodiversity means there is more genetic diversity and variation this allowing a population to effectively evolve and adapt through natural selection.

low biodiversity= low ecosystem stability, resilience, inertia

38
Q

what are selection pressures

A

any feature of th environment that reduces the fitness of any particular phenotype in a population of organisms
- competition for food, mates space resources
predators, climate

habitat destruction
- land clearing: agriculture, mining housing
CLIMATE CHANGE
-effects the weather patterns, pollution
- introduced species

human activities have acclerated the rate of change in natural environments to such as extent that populations to not have enough time the adapt through natural selection.

39
Q

how do transgenic organisms have adverse effects on genetic diversity and environment

A
  • the effects on non-transgenic organisms
  • more rapid eveolution of pesticide resistant species
  • the possibily of geneflow from crop species to weeds species resulting in super weeds
40
Q

decribe evolution of resistance

A
  • variation in population
  • selection pressure ( herbicide = round up)
  • some individuals survive due to resistance to herbicide
  • survivors pass this trait to offspting
  • farmers then need to increase herbicide in order to kill weeds that have higher tolerance
41
Q

what bio technology is used in evolution?

A

bioinformatics, comparative biochemistry, comparative genomics

42
Q

what is bioinformatics

A

the science of collecting and analysing large sets of biological data using computer modeling

43
Q

what is comparative biochemistry and genomics

A

comparative biochem- the study of evolutionary relationships between organisms based of differences in genomics

comparative genomics- comparision of the genome sequences of different species. enabling identification of genes that are conserves or common among species as well as genes.

44
Q

describe what biogeography in conservation is and why its important to consider.

A

the study of geographical distribution of living things and gow those distributions relate to the environment, the origins of species and the changes that have occured over time. focusing of environmental abd human factors.

conservation areas to to be large enough tohave suitabe conditions ot maintain viable popualtions e.g wild life corridors which provide links to other conservation areas promoting gene flow

change in location could also mean that indiv could be reproductively imcompatible, outbreeding depression and reduced fitness

45
Q

why are reproductive behivors important for biologist to understand

A

so they can recreate conditions similar tohow they reproduce in wild to the zoos. if they dont replicate this it can reduce the number of indiv that reproduce

reproduction in zoos also could promote outbreeding depression

46
Q

what are population dynamics in conservation

A

understanding how and why populations change in size

  • birth death immegration and emmigration
47
Q

carbon dating is most useful for determining the objects of how old

A

less than 12 000 yrs old

48
Q

Explain why small populations are more at risk of extinction than large populations

A

larger populations have amore diverse gene pool
and can draw on alternate allelss if selection pressures change

49
Q

Describe how wildlife corridors can ensure sufficient gene flow between fragmented populations

A

wild life corridors are areaS of preserved natural ecosytem that connect wildflife reserves to on another

  • increase the size of the reserve and can supprt more indivudulas
  • they allow indiv to move between reserves, increasing mating partner selection and therfore gene flow
50
Q

Explain what may happen to the fragmented populations of a threatened species if wildlife corridors are not available

A

-reproductive isolation (no geneflow)
-genetic drift due to small population numbers
-change in selection pressures may change allele frequency
- genetic diversity may decrease in the small populations increasing threat of extinction

51
Q

Briefly explain the three (3) main processes that work simultaneously to support the evolution of species diversity.

A

natural selection
- selective pressures that favour phenotypes more adapted to its environment

speciation
- accumilation of differences from the original popoulation to form a new and distinct species

macroevolution
- the accumulation of microevolution over large taxanomic groups to form many new speces over time

52
Q

Most species of birds and frogs have evolved different calls over time to communicate and attract mates.

Explain how this is an example of a reproductive isolating mechanism.

A

Behavioural mechanism for courtship (1 mark).

Attracted to and mate with individuals that make the same sound/call (1 mark).

Ensure only mate with own species – reproductive isolation (1 mark).

53
Q

Identify and define the two different forms of speciation. Provide an example for each.

A

Allopatric speciation

Physical separation and disruption of gene flow between individuals of a species due to a geographical barrier

Eg. Finches on Galapagos Islands, Marsupials in Australia, Eucalyptus species in different climates and ecosystems.

Sympatric speciation

Evolution of two (2) or more species from a single population in the same area without physical separation.

Eg., Panther chameleon in Madagascar, frogs inhabiting the same lake/swamp, Kiwis in New Zealand.

An explanation of genetic separation occurring due to differences in mating times, discovery of new food resource, altered courtship ritual.

54
Q

define what species is

A

a group of organisms that interbreed to produce fertile offspring. individuals cannot breed with other species

55
Q

explain how species evolve by allopatric speciation

A

a geographical barrier devides population preventing gene flow and the environmental pressures on either side of the barrier are different. populations on either side are different due to natural selection. the differences will accumulate overtime and individuals are no longer able to breed.

56
Q

describe how genetic drift affects the genetic composition of populations

A
  • changes allele frequencies
  • changes are random or occur by chance
  • (causes) loss of diversity/alleles from a population
57
Q

explain how a phylogenetic tree can represent the evolutionary relationship among different species

A
  • branching of the tree represents the relationships
  • recent species are the tip of the tree
  • shared common ancestors are at the trunk of a tree
  • trees constructed from DNA data which reflect relationship
58
Q

what are different types of comparative studies of biochemistry

A

DNA sequences
- protein sequences
- dna hybridisation
- mitochondrial dna

59
Q

what causes a change in allele frequency in gene pools

A

mutation, differing selection pressures, genetic drift and changing gene flow between groups

60
Q

the early evolution and diversitification of eukaryotes required increasinf amounts of which gas?

A

oxygen

61
Q

a mutation in a dna sequence results in the substitution of ne amino acid for another in a protein production. this mutation has produced a new what in dna

A

new allele

62
Q

variation in the height of pea plants is discontinuous. variation in the heigh of wheat is continuous this suggest the height of pea plants is controlled by

A

a single allele where as height in wheat is controlled by multiple genes

63
Q

genetic differences between populations are reduced by what

A

geneflow as they allow for genes to flow between population increasing genetic variation

BIO UNIT 3/4 (12 decks)

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