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biology year 12 > speciation > Flashcards

speciation Flashcards

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1
Q

speciation extended response, 4 steps

A 
variation:
- mutation
- random assortment
- crossing over
- migration
isolation: 
allopatric or sympatric, split into 2 habitats with new environments, geographic or reproductive 
natural selection:
- favors the best suited phenotype, 
speciation:
- the 2 populations are no longer able to breed
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2
Q

antibiotic resistance

A

antibiotics: drugs that kill bacteria by interfering with the metabolic processes
- affected people are treated with antibiotics
- antibiotics kill bacteria / cure most individuals
- stop the spread of the disease
- bacterium squired resistance through mutation
- those bacteria were unaffected by the antibiotic
- antibiotic bacteria continued to reproduce
- resistant bacteria becomes more common
- natural selection favored the antibiotic resistance strains
- antibiotic represents a changed environment

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3
Q

insecticide resistance

A
  • are pesticides used to control pest insects

- form of natural selection in which the most resistance organisms survive to pass on their genes to their offspring

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4
Q

types of speciation

A

allopatric: geographical isolation, evolution of two or more species in the presence of a physical barrier
sympatric: reproductive isolation,

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5
Q

speciation

A

ancestral species diverge into 2 or more species unable to interbreed due to biological or behavioral barriers

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6
Q

reproductive barriers / sympatric

A

prezygotic: pre fertilization, different habitats, incompatible behavior
post zygotic: post fertilisation, egg and sperm fail to meet

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7
Q

ecological / microhabitats

A

species occupy different microhabitats within the same area

eg forms in forrests, frogs in streams

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8
Q

temporal isolation

A

species have different activity patterns

  • nocturnal, diurnal
  • different breeding seasons
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9
Q

behavioral isolation

A

specific calls, rituals to recognize potential mates

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10
Q

intersexual isolation

A

between 2 sexes preference by one sex for the features of the other sex

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11
Q

intrasexual selection

A

within one sex, competition between members of one sex usually males

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12
Q

conservation strategies

A

populations with reduced genetic diversity face increased risk of extinction

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13
Q

conservation planning to maintain viable gene pools includes considerations of biogeography, reproductive and population dynamics

A
  • Tasmanian devils are dying from facial tumor disease
  • spread by biting when feeding and mating
  • tumors make it difficult to eat therefore death by starvation
  • now endangered
    biogeography:
  • aim to ensure wide geographical spread to several sites to reduce effects of disease and catastrophe
  • in many institution, free ranges enclosures, zoos
    reproductive behavior:
  • mate selection: multiple making increase biodiversity
  • females must replace itself and its partner, therefore min 2 kids
  • parental care: suckled in pouch and protected until 2yr
    population dynamics:
  • aim to maintain a healthy biodiversity
  • select healthy young disease free
  • quarantine to ensure disease free then relocate
  • ensure high population, enough to cope with genetic drift
  • maximise and maintain genetic diversity
  • ensure all founding animals contribute to gene pool
  • protect food: supply and habitat
  • reduce predators
  • monitor breeding and remove devils who’s genes are well represented
  • fence protect and monitor
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14
Q

biogeography conservation

A
  • nature reserves need to be large enough and have suitable conditions
  • small populations lose genetic diversity
  • need connections between reserves so populations can exchange genes
  • exchange will boost diversity
  • populations of a species in different locations will be genetically different because they evolved in different species
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15
Q

reproductive behavior, conservation

A
  • behavior associated with mating
  • behavior may change in captivity
  • this could mean only a small population of individuals reproduce and produce surviving offspring
  • gene pool would only reflect the genes of those individuals
  • high levels of inbreeding
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16
Q

population dynamics

A
  • how and why population sizes change
  • population sizes fluctuate
  • population will loose genetic diversity when small
  • happens through genetic drift
  • conservation planning should be based around small populations
  • can identify and possible correct the factors that cause numbers to drop
17
Q

allopatric speciation

A
  • population is divided by a physical barrier such as a mountain or river
  • preventing them from moving
  • no gene flow between populations
  • evolve differently
  • different environments therefore face different selection pressures
  • natural selection will favor different traits
  • result in different allele frequencies
  • populations will adapt to different environemtns
  • genetic differences increase over time
  • eventually unable to interbreed because individuals no longer compatible
  • once they are unable to interbreed they are considered different species
  • they evolve differently in their locations
18
Q

how genetic drift changes allele frequency

A
  • random changes in allele frequency that occur as a result of chance events and not natural selection
  • can result in a loss of alleles
  • occurs in small populations
  • non - directional
19
Q

how does gene flow change allele frequency

A
  • changes in allele frequency due to migration

- occurs when alleles are added to a gene pool due to the movement of individuals from one population to another

20
Q

consequence of a deletion

A
  • proteins are essential to cell structure and function
  • proteins catalyse cheimcal reactions, provide structural support and are cell communications
  • absence of essential protein could disrupt cell structure and cause the cell to die
21
Q

how can environmental factors cause mutations

A

a mutation is a (permanent) change in the structure of DNA
 environmental factors can cause changes in the structure of DNA
 physical mutagens e.g. radiation/ultra violet light
 produce energy (that damages/changes the structure of DNA/gene)
 chemical mutagens - e.g. alcohol, smoke, mustard gas
 may substitute a base or add/remove bases or change the chemical properties of a base (depends on chemical)
 biological mutagen example of a type of virus/bacteria/microorganisms that infect cells (and damage/change DNA of the cell)
 specific example of the action of a mutagen (e.g. ultra violet light cause adjacent bases in DNA to bind together

22
Q

how can errors in meiosis cause mutations

A

 (normal meiosis) members of homologous pair go to opposite poles/different gametes
 (errors in meiosis) can result in both members of a homologous pair going to same pole/non-disjunction
 will be an extra chromosome at this pole/chromosome missing from other pole
 (results in gametes/cells) with extra or missing chromosomes
 (if gamete is fertilised can get an) individual with an extra or a missing chromosome

23
Q

why are populations with reduced genetic diversity at high risk of extinction

A

(population) cannot evolve/adapt/change/respond
 to changing environment or diverse/heterogeneous environment
 because all/most individuals are the same or there are no/few genetic differences among individuals/small gene pool
 natural selection requires/operates on differences among individuals
 disease can spread (quickly) through population
 no/few resistant individuals or all/most individuals are susceptible

24
Q

how can biotechnology reduce risk of extinction

A

monitor the gene pool of the population/DNA profiling of individuals in populations
 identify at risk populations
 can then protect or intervene
 assess the gene pool for breeding programs
 identify/select genetically suitable/more distantly related breeding
individuals (from within the population)
 introduce (genetically different) individuals from other populations
 to increase genetic diversity in the population
 genetically modify individuals/gene therapy/recombinant DNA technology
 can introduce genes from other populations/species or directly edit genes
 create genetically superior types
 (modified) individuals can better cope with a particular
threat/disease/adverse condition
 artificially propagate individuals (especially plants)
 specific example -collect eggs and sperm from endangered animal and implant embryo in common
species
 to increase the number of individuals

25
Q

bottleneck

A

when a catastrophic event occurs or when a period of adverse conditions leads to a decrease in population size and loss of alleles from a gene pool

26
Q

founder effect

A

a few individuals carry alleles to a new isolated area and a new population is formed with different allele frequencies to the original population
- decrease in variation

biology year 12 (23 decks)

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