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Biology Year 12 > Classification and evolution✅ > Flashcards

Classification and evolution✅ Flashcards

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1
Q

define classification and species

A

classification: the sorting of organisms into groups

species: a group of organisms that can interbreed to produce fertile offspring

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2
Q

what are the advantages of classification systems

A

analyse evolutionary relationships between organisms

predict characteristics (as species grouped together are likely to share characteristics) and identify species

share research findings (without confusion or ambiguity)

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3
Q

what are the 5 kingdoms

A

Prokaryotae, Protoctista, fungi, plantae, animalia

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4
Q

describe the prokaryotae kingdom
uni or multicellular, domain(s), organelles present, cell wall, how do they gain nutrients

A

unicellular
bacteria and archaea domains
no organelles
yes (peptidogylcan/murein) cell wall
autotrophic or heterotrophic

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5
Q

describe the protocista kingdom
uni or multicellular, domain(s), organelles present, cell wall, how do they gain nutrients

A

unicellular or multicellular
eukarya domain
yes organelles
no cell wall
autotrophic or heterotrophic

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6
Q

describe the fungi kingdom
uni or multicellular, domain(s), organelles present, cell wall, how do they gain nutrients

A

unicellular or multicellular
eukarya domain
yes organelles
yes (chitin) cell wall
saprotrophic (extracellular digestion)

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7
Q

describe the plantae kingdom
uni or multicellular, domain(s), organelles present, cell wall, how do they gain nutrients

A

multicellular
eukarya domain
yes organelles
yes (cellulose) cell wall
autotrophic

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8
Q

describe the animalia kingdom
uni or multicellular, domain(s), organelles present, cell wall, how do they gain nutrients

A

multicellular
eukarya domain
yes organelles
no cell wall
heterotrophic

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9
Q

what are 3 domain system

A

bacteria, archaea, eukarya

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10
Q

what is added to the 5 kingdom system to become the 6 kingdom system

A

archaebacteria

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11
Q

why have domains been introduced

A

Woese domain classification based on several molecular observations, which include;

bacteria cell walls contain peptidoglycan but those of archaea do not

the RNA polymerase of Archaea contains 8-10 subunits, but bacterial RNA polymerase contains only 5 subunits

archaea have rRNA that is different to the rRNA of bacteria and eukarya

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12
Q

what is phylogeny

A

the study of evolutionary relationships between organisms

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13
Q

explain why the structure of a phylogenetic tree may change over time (2 marks)

A

new evidence (such as comparative genetics)

the evolutionary relationships between species are re-evaluated

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14
Q

suggest what advantages phylogenetic classification has over traditional hierarchical taxonomic classification (3 marks)

A

evolutionary positions can be compared/ evolutionary histories can be mapped

phylogenetic trees avoid arbitrary groupings of species

the use of genetic and evolutionary comparisons enable more precise classification

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15
Q

state 2 differences between bacteria and fungi (2 marks)

A

bacteria have peptidoglycan in their cell walls/fungi have chitin in their cell walls

bacteria are always unicellular, whereas some fungi are multicellular

bacteria lack organelles

fungi can feed using saprotrophic nutrition

fungi have hyphae

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16
Q

explain why classification systems have changed over time, using the introduction of domains as an example (4 marks)

A

new evidence shows different relationships

example of new evidence (eg DNA sequencing)

2 examples of the evidence used in domain classification (eg RNA polymerase, cell wall structure, rRNA)

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17
Q

what is the three types of evidence for evolution

A

palaeontology (fossils)
comparative anatomy
comparative biochemistry

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18
Q

what evidence does palaeontology (fossils) show for evolution

A

fossils of simple organisms tend to be found in the oldest rocks, whereas more complex organisms are found in more recent rocks

plant fossils appear in older rocks, before animals which matches their ecological relationship

similarities between different fossil species reveal gradual anatomical change

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19
Q

how does comparative anatomy show evidence for evolution

A

homologous structures (anatomical features that have slight differences but same underlying structure) provide evidence of divergent evolution

the embryos of related species have similar appearances, despite considerable interspecific differences between adults. This indicates that different species have evolved from a common origin

20
Q

how does comparative biochemistry show evidence for evolution

A

the rate of mutations in DNA can be calculated. This enables evolutionary relationships to be analysed. The closer the relationship between 2 species, the fewer the differences in their DNA sequences

21
Q

what was Charles Darwin influenced by

A

Charles Lyell’s geological theories: fossils are evidence of animals living millions of years ago and natural process can result from gradual changes and accumulations

His observations on Galapagos Islands (slight difference in beaks and claws) between species on neighbouring islands developed adaptations

his studies on artificial selection by pigeon breeders enabled him to draw parallels with how natural selection might work

22
Q

what can the DNA base sequence of 2 species tell us about their evolutionary relationship (2 marks)

A

the greater the similarities in the base sequences

the closer the evolutionary relationship

23
Q

suggest why the fossil record fails to provide complete picture of evolutionary history (3 marks)

A

gaps/missing links in the record

some species do not fossilise

some fossils have been destroyed since formation

24
Q

Explain how the parallels between artificial selection and natural selection that Darwin observed (3 marks)

A

variation exists (between individuals within population)

both artificial selection and natural selection involves individuals with favoured traits breeding

in both cases the favoured traits are inherited by offspring

over many generations alleles frequencies change within the populations

25
Q

how can genetic variation be produced

A

DNA mutation
crossing over
independent assortment
random fertilisation

26
Q

how does environmental variation affect variation

A

results from a combination of environmental and genetics

EG potential height someone can grow is genes but their environment can influence whether or not they grow to this height eg poor diet

27
Q

describe how genetic variation can be introduced into a species (4 marks)

A

mutation

changes DNA base sequence

crossing over

and independent assortment of homologous chromosomes and chromatids

produce new combinations of alleles

random fertilisation/ mating (increases number of possible allele combinations)

28
Q

describe discontinuous variation
in terms of nature of the data, genetic influence, environmental influence, how it is represented and examples

A

nature: discrete values with no intermediate values

genetic influence: one gene or a small number of genes

Environmental influence: no

how is it represented: bar chat/ pie chart

examples: gender, blood groups, bacterial shape

29
Q

describe continuous variation
in terms of nature of the data, genetic influence, environmental influence, how it is represented and examples

A

nature: a range of values (i.e a continuum)

genetic influence: several genes (polygenic)

Environmental influence: yes

how is it represented: histogram

examples: height, weight, number of pollen grains produced

30
Q

what is a normal distribution curve, when does it normally occur

A

a symmetrical, bell-shaped curve where most values lie close to the mean

a trait that shows continuous variation

31
Q

what does a high standard deviation value indicate

A

that the data shows a lot of variation

32
Q

how do you calculate the standard deviation

A
  1. calculate the mean by dividing sum of measurements by number of individuals sampled
  2. mean value then subtracted from each of the measured values
  3. these differences then squared and the squared differences are added together
  4. the sum of squared differences is divided by sample size minus 1
  5. find square root of the value
33
Q

what is a students T test used for

A

to compare 2 sets of data

34
Q

how do you calculate the T value and determine the null hypothesis

A
  1. work out degrees of freedom in the test (total number of samples from both sets of data minus 2)
  2. use table of probabilities to find probability value for your T value corresponding to correct degrees of freedom
  3. the probability value tells you likelihood of the difference between 2 data sets being due to chance
  4. reject null hypothesis if there is a less than a 5% probability that the difference is due to chance. A p value of 0.05 or less tells you there is a significant difference
35
Q

what are the 3 types of adaptations

A

anatomical, behavioural, physiological

36
Q

give description and example of the anatomical adaptation

A

physical structures EG. communication, locomotion, feeding, water regulation

37
Q

give description and examples of behaviour adaptations

A

simple, innate behaviours (such as reflexes) through to more complex (learned) behaviours
EG. communication, locomotion, responding to seasonal changes

38
Q

give description and examples of physiological adaptations

A

biochemical and cellular traits (eg type of enzymes and hormones an organism produces)

EG. feeding, antibiotic resistance, adaptations to temperature

39
Q

what is convergent evolution, give some examples

A

unrelated species living in similar habitats and face similar selection pressures, results in species evolving, independent of each other, similar structures

leaves

ability to produce silk threads-weaver ants, spiders, silk moths

whales and dugongs- evolved similar tail flukes

echolocation

40
Q

what type of adaptations are these following adaptations
A: sweating
B: phototaxis
C: opposable digits
D: lactose tolerance (4 marks)

A

A: physiological
B: behavioural
C: anatomical
D: physiological

41
Q

Aye-aye lemurs (order: primates) and striped possums (order: Diprotodontia) both have elongated fingers that they use to locate invertebrates in trees. Explain why this is an example of convergent evolution (3 marks)

A

the 2 species possess similar traits

as adaptations to similar ecological niches

but the adaptations evolved independently/ at different times

42
Q

what steps are required for natural selection

A

1.Variation must exist within the population
2. presence of a selection pressure (a factor that affects the organisms chance of survival
3.Only individuals possessing traits enabling them to overcome the selection pressure will survive and reproduce
4. The gene variants (alleles) that enabled the survival in presence of selection pressure are passed on to next generation
5. Over many generations the allele frequencies in the population will change and balance of phenotypic characteristics will change accordingly to suit populations habitat
6. when series of mutations arises in a population, natural selection can result in speciation (formation of new species)

43
Q

state 3 examples of a selection pressure that bacterial species may encounter (3 marks)

A

pH changes
temperature changes
a lack of water
antibiotics
destruction by cells in their hosts immune system

44
Q

describe one example of an adaptation evolved in another species that benefited humans (2 marks)

A

eg nylonase production in flavobacterium

this enables industrial waste to be removed

45
Q

Humans have developed insecticides to kill insects, explain how a species of insect could become resistant to an insecticide (4 marks)

A

insect species has variation between its members

insecticide acts as a selection pressure

only individuals that have some resistance will survive, reproduce and pass on beneficial allele to offspring

over generations, proportion of alleles for resistance will increase and entire population will be resistant to insecticides

Biology Year 12 (8 decks)

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