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3: Classification & biodiversity Flashcards

classification, natural selection, biodiversity (58 cards)

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1
Q

Outline the different levels of the classification system

A

domain
kingdom
phylum
class
order
family
genus
species

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2
Q

what is the definition of species

A

species is a group of organisms with similar characteristics which interbreed to produce fertile offspring

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3
Q

what are the limitations of the definition of a species

A
  • cannot be applied to organisms that reproduce asexually
  • hybrids are as a result of different species interbreeding BUT they sometimes produce fertile offspring. BUT not counted as species
  • if the organism is are extinct then you can’t know
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4
Q

why is it often difficult to assign organisms to any one species or to identify new species

A

-there is variation within species so individuals may look different from each other
-some different species can interbreed to produce fertile offspring

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5
Q

how can gel electrophoresis be used to distinguish between species
and determine evolutionary relationships?

A

-gene is cut into fragments using enzymes and placed in gel
-electricity is applied
-nucleotides are slightly negatively charged so they move through gel towards positive side
-big fragments don’t travel very far as they are heavier
-small, lighter fragments travel faster + move further

-By comparing banding patterns, similarities and differences in DNA can be observed.

More similar banding patterns suggest closer evolutionary relationships

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6
Q

describe the 2 things can be used to distinguish between species and determine evolutionary relationships

A

DNA sequencing - reveals DNA sequences from different species which can be compared to determine ancestry by determining genetic differences between species

bioinformatics - analyses DNA/protein sequences and can compare large amounts of genetic data quickly and accurately

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7
Q

why can DNA sequencing be used to distinguish species and determine evolutionary relationships

A

because its passed from generation to generation

and can be extracted from cells and base sequences using machines

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8
Q

what is taxonomy

A

the science of classifying organisms

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9
Q

what are the 3 parts to classifying organisms (taxonomy)

A

1) hierarchal structure - species with similar characteristics whitin larger groups. No overlap between groups

2) taxation - each rank in heirarchy has a name. 8 groups

3) binomial nomenclature - 2 parts to name, Genus, species (genus is capital, species no capital)

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10
Q

what is phylogenetics

A

study of evolutionary relationships between organisms using phylogenetic trees

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11
Q

describe a phylogenetics tree from past to present and present to past

A

past to present = speciation event

present to past = common ancestor - closest to present is most recent common ancestor

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12
Q

what is the role of scientific journals in validating new evidence supporting the accepted scientific theory of evolution

A

Publishing evolutionary research (e.g. fossil discoveries, DNA evidence) ensures the data is available for scrutiny and supports the theory of evolution

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13
Q

what is the role of the peer review process and scientific
conferences in validating new evidence supporting the accepted scientific
theory of evolution.

A

research is viewed by peers to check for accuracy, validity and to prevent false claims

in scientific conferences, other researchers can challenge findings which allows rapid sharing and discussion of new evolutionary findings

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14
Q

describe 5 kingdom model

A

Proposed by Whittaker

Divided organisms into:
Prokaryotae
Protoctista
Fungi
Plantae
Animalia

each kingdom was classified based on
-cell type (eukaryotic/prokaryotic)
-nutrition method
-presence of cell wall

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15
Q

describe 3-domain model (alternative to 5 kingdom model)

A

Proposed by Carl Woese

Based on comparisons of RNA and DNA sequences

Divides life into three domains:
1) Bacteria
2) Archaea (ancient prokaryotes)
3) Eukarya (eukaryotes)

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16
Q

what is the evidence for the three domain model as an alternative to the five kingdom model

A

Molecular evidence showed Archaea are more closely related to Eukarya than to Bacteria
(eg. archaea and eukarya use same enzymes for transcription and translation)

genetic sequencing also showed major differences in cell membrane structure and response to antibiotics between archaea and bacteria

but The Five-Kingdom model grouped all prokaryotes together, which overlooked these differences

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17
Q

what is the role of the scientific community in validating the evidence for the three domain model

A

Woese’s findings were:
-Published in peer-reviewed journals
-Reviewed, tested and repeated by other scientists which gained validity
-presented at scientific conferences for discussion

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18
Q

what were darwins 3 key observations

A
  1. organisms produce many more offspring than survive to be mature individuals
  2. individuals in a species are not all identical due to crossing over, independent random assortment and random fusion of gametes
  3. natural selection results in survival of offspring with favourable characteristics
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19
Q

what does every population have

A

VARIATION

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20
Q

what is a selective pressure

A

selective pressure is an external environmental factor that acts on an individual eg water

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21
Q

outline steps of evolution by natural selection

A

1) variation within population caused by mutations
2) change in selective pressure means some have beneficial allele
3) organisms without advantageous allele die and ones with survive and reproduce
4) beneficial allele inherited
5) frequency increases

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22
Q

what is a niche

A

the abiotic and biotic things an organism interacts with

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23
Q

what are the 3 types of adaptations

A

anatomical
physiological
behavioural

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24
Q

what is anatomical adaptation, how does it help an organism

give an example

Study These Flashcards
A

anatomical - physical features of structure of organism which enhance survival by helping organisms with movement, feeding or temp control

eg cacti have spines instead of leaves to reduce water loss in a hot climate

25
what is a physiological adaptation, how does it help an organism give an example
internal body processes (chemical metabolism) that increase survival by allowing organisms to function efficiently in specific environments. eg thermophilic archaea - proteins dont denature and membrane lipids are stable at very high temps
26
what is behavioural adaptation, how does it help organism give an example
changes to behaviour of organism that improve survival by helping them escape predators, cope with conditions or reproduce successfully eg mating behaviour of birds (singing/dancing) to attract a mate and reproduce successfully eg nocturnal animals are active at night to avoid heat or predators
27
what are antibiotics made from and what do they target, why can they target them, and how do they do it
made from fungi target harmful bacteria and can because antibiotics work on peptidoglycan cell wall antibiotics prevent cell wall formation
28
why dont antibiotics work on viruses
because of capsid (protein wall), antibiotics ONLY affect peptidoglycan cell wall
29
outline steps of antibiotic resistance by natural selection
variation within bacteria caused by mutations presence of antibiotics (selective pressure) results in beneficial allele (resistance) of some bacteria resistant bacteria survive and reproduce frequency of resistant bacteria increases
30
for 2 populations of same species to become different species, what must they be
REPRODUCTIVELY ISOLATED
31
what is gene flow
gene flow = where organisms can breed from 1 population to another in same species
32
what are the 2 types of speciation and compare them
allopatric and sympatric allopatric and sympatric speciation BOTH HAVE GENE FLOW allopatric and sympatric BOTH FORM NEW SPECIES allopatric is separation by physical, geographical barrier WHEREAS sympatric has no separation by barriers allopatric has different SELECTIVE PRESSURES WHEREAS sympatric has diff types of ISOLATION
33
when does allopatric speciation happen and outline steps of it
happens when 2 populations of same species become geograhically separated eg migration/earthquakes 1) interbreeding population so gene flow 2) physical barrier so reproductively isolated so NO GENE FLOW ANYMORE 3) both populations are under different selective pressures now eg temperature so beneficial allele caused by mutation arises 4) those with beneficial allele survive + reproduce so allele frequency increases + continues being inherited until entire population has it 5) now each population is a new species 6) CANT BREED TOGETHER NO GENE FLOW because different species now
34
when does sympatric speciation happen and what causes it
when 2 populations become reproductively isolated in SAME GEOGRAPHICAL LOCATION due to: - ecological isolation = live in different ecosystems -temporal/seasonal isolation = reproduce at different times of day/season -mechanical isolation = mating difficulties due to physical characteristics -behavioural isolation = different courtship patterns -genetic isolation = gametes dont fuse
35
what are ecological, temporal/seasonal, mechanical, behavioural and genetic isolations caused by
RANDOM MUTATIONS
36
what are subspecies
populations of same species that are currently isolated and may become distinct species over many generations
37
is isolation is removed, how do subspecies breed
subspecies will interbreed as a single species
38
outline sympatric isolation steps
- no gene flow due to reproductive isolation - eg seasonal isolation BECAUSE reproduce at different times of year (HAVE TO EXPLAIN WHY E.G SEASONALLY ISOLATED) - due to random mutations - beneficial allele inhertied - frequency increases OVER MANY GENERATIONS - become different species
39
how is there an evolutionary arms race between pathogens and medicines
- variation within pathogen population caused by mutations - presence of antibiotics/medicine (selective pressure) results in beneficial allele (resistance) of some bacteria - resistant bacteria survive and reproduce resistant allele is inherited so frequency of resistant bacteria increases - over time medicine becomes less effective so new treatments must be developed
40
what are the problems of the arms race between pathogens and development of medicines
new drugs must be developed continuously because pathogens evolve rapidly due to high mutation rates misuse or overdose of antibiotics speeds up resistance
41
what is biodiversity
variation of all living organisms in a particular habitat
42
what is genetic diversity
number of alleles in a population
43
what is habitat diversity
number of species in a habitat
44
what is species abundance
number of individuals per unit area
45
what is species richness
number of different species in 1 area at 1 time
46
what is the biodiversity index and give equation
it takes abundance and species richness into consideration D = N (N-1) / Σ (n-1) N = total number of individuals n = number of organisms in each species
47
how can biodiversity be assessed at different scales
within a habitat at the species level using simpsons biodiversity index AND within a species at the genetic level by looking at the variety of alleles in the gene pool of a population
48
what are the causes of reduced biodiversity
- introduction of new species - deforestation - poaching - global warming - commercial farming
49
how does introduction of new species, deforestation and poaching reduce biodiversity
- introduction of new species: eg honeybees , competition for resources like nectar so other flying insects will decline in number - deforestation: loss of habitat so less plant species - poaching: number of individuals decrease so less reproduction
50
how does global warming and commercial farming reduce biodiversity
- global warming: droughts lead to less plants growing - commercial farming: hedgerows cut down which reduces nesting sites for many. Hedgerows provide food so less food for animals
51
explain why organic farms have a higher diversity than modern day farms
organic farms dont use herbicides there were more niches and breeding areas due to more plant areas
52
what are the ethical reasons for conservation being important to increase biodiversity
genetic resource - genes for future to cure disease biodiversity should be preserved for future generations conservation can help preserve indigenous people + their ways of life
53
what are the economic reasons for maintenance of biodiversity
1. recreation + education 2. for food, water, raw materials 3. for medicinal resources
54
what are the 2 ways to conserve, define them and give examples
1. in situ conservation - conservation in natural habitat eg protected habitats (national parks, safaris) 2. ex situ - conservation outside of natural habitat eg zoos, seedbanks
55
what are the advantages of insitu conservation
- large numbers of plants and animals can be conserved so large genetic diversity - can be popular tourist destinations which helps them to fund +educate visitors - breeding programmes
56
what are disadvantages of in situ conservation
- many important protected areas are in poor countries and it can be expensive to maintain and protect a large area - commercial and political interests eg poachers, loggers compete with conservation interests and often win
57
advantages of ex situ conservation
-well managed breeding programmes can maintain and even improve genetic diversity - animals and plants endangered in the wild can be protected in zoos and botanic gardens - since zoos are cheaper + easily accessible, they attract large numbers of visitors which helps raise funds and educate on importance of conservation
58
what are disadvantages of ex situ conservation
- zoo environment can be small and unnatural for large animals and they dont have the same social interactions - only a small number of plants + animals can be conserved with ex situ with a correspondingly low genetic diversity - young animals do not learn natural skills from observing families and peers in natural environments

Biology (5 decks)

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