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biology > 4.2.2 classification and evolution > Flashcards

4.2.2 classification and evolution Flashcards

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1
Q

what is a taxonomic group?

A

the hierarchical groups of classification - domain, kingdom, phylum, class, order, family, genus, species

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2
Q

why do scientists classify organisms?

A
  • to identify species
  • to predict characteristics
  • to find evolutionary links
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3
Q

what is a species?

A

a group of organisms that are able to reproduce to produce fertile offspring

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4
Q

what is binomial nomenclature?

A

the scientific naming of a species with a Latin name made of two parts - the first indicating the genus and the second the species

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5
Q

KINGDOM

what are the features of protoctista?

A
  • eukaryotes
  • mainly unicellular
  • nucleus and membrane-bound organelles
  • some have chloroplasts
  • some are sessile, some have cilia, flagella, amoeboid mechanisms to move
  • some are autotrophic, heterotrophic or both
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6
Q

KINGDOM

what are the features of fungi?

A
  • eukaryotes
  • unicellular or multicellular
  • nucleus and membrane-bound organelles
  • no chloroplasts
  • cell wall composed of chitin
  • no mechanisms of locomotion
  • saprophytic
  • store food as glycogen
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7
Q

KINGDOM

what are the features of plantae?

A
  • eukaryotes
  • multicellular
  • nucleus and membrane-bound organelles
  • chloroplasts
  • cell wall composed of cellulose
  • most are sessile, some have gametes that move using cilia or flagella
  • autotrophic
  • store food as starch
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8
Q

KINGDOM

what are the features of animalia?

A
  • eukaryotes
  • mainly unicellular
  • nucleus and membrane-bound organelles
  • no chloroplasts
  • move with aid of cilia, flagella or contractile proteins
  • heterotrophic
  • store food as glycogen
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9
Q

KINGDOM

what are the features of eubacteria?

A
  • prokaryotes
  • unicellular
  • no nucleus or membrane-bound organelles
  • can live in extreme environments
  • nutrients absorbed through cell wall or produced by photosynthesis
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10
Q

KINGDOM

what are the features of archaebacteria?

A
  • prokaryotes
  • unicellular
  • no nucleus or membrane-bound organelles
  • cell walls contain peptidoglycan
  • nutrients absorbed through cell wall or produced by photosynthesis
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11
Q

DOMAIN

what are features of eukarya?

A
  • eukaryotes
  • 80s ribosomes
  • RNA polymerase contains 12 proteins
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12
Q

DOMAIN

what are features of archaea?

A
  • prokaryotes
  • 70s ribosomes
  • RNA polymerase contains between 8 and 10 proteins
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13
Q

DOMAIN

what are features of bacteria?

A
  • prokaryotes
  • 70s ribosomes
  • RNA polymerase contains 5 proteins
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14
Q

what is phylogeny?

A

the evolutionary relationships between organisms

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15
Q

what are phylogenetic trees?

A

a diagram used to represent the evolutionary relationships between organisms
they are branched diagrams, which show that different species have evolved from a common ancestor

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16
Q

what are the advantages of phylogenetic classification?

A
  • takes into account evolutionary relationships that are not obvious by looking at characteristics
  • phylogeny produces a continuous tree whereas classification requires discrete taxonomical groups - means organisms are not forced into groups where they do not fit
  • it is not hierarchical - groups on the tree are represented according to evolutionary position - allows species to be compared, shows extinct species, shows different levels of diversity, shows different degrees of biological differentiation
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17
Q

why are prokaryotes classified as two separate domains?

A
  • cell walls differ - peptidoglycan not found in archaea
  • advances in biological techniques have identified large differences in composition
  • rRNA and ribosomes differ
  • old classification does not show correct phylogeny
  • archaea and eukarya have a more recent common ancestor
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18
Q

how and why have classification systems changed over time?

A
  • earliest classification systems were based off visual similarities between organisms
  • 2 kingdom system - animals (moved and eat) and plants (didn’t move or eat but grew)
  • Whittaker introduced 5 kingdom classification system (plantae, animalia, fungi, protoctista, prokaryotes) - scientific advances and the use of microscope allowed smaller detail to be observed like differences in cell structure
  • Woese introduced 3 domain and 6 kingdom classification system - advances in science allowed DNA and proteins to be studied providing evidence for evolutionary relationships
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19
Q

how did the theory of evolution develop?

A
  • Hutton - proposed principle of uniformitarianism - earth shaped by sedimentation in rivers, wind erosion, ash and lava deposits from volcanic eruptions
  • Lyell - suggested that fossils were evidence of animals that lived millions of years ago
  • Darwin - theory of evolution by natural selection - observations of finches beaks being adapted to food available on island
  • Wallace - theory of evolution by natural selection
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20
Q

what evidence is there for the theory of evolution?

A
  • palaeontology - study of fossils and fossil record
  • comparative anatomy - homologous structures (structure that appears superficially different in different organisms but has the same underlying structure) suggest a common ancestor. homologous structures provides evidence for divergent evolution (species evolved from a common ancestor, with a different set of adaptive features for a new habitat as a result of migration or loss of habitat)
  • comparative biochemistry - study differences and similarities in proteins and DNA - closely related species have most similar DNA and proteins, changes in highly conserved molecules can help identify evolutionary links such as cytochrome C and ribosomal RNA
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21
Q

what are the advantages of the fossil record?

A
  • radioisotopes can be used to date fossils
  • chronological order apparent in rock strata
  • changes can be tracked over time
  • allows relationships between extinct and living organisms to be investigated
  • studying anatomy of fossil organisms show how closely related organisms have evolved from the same ancestor
22
Q

what are the disadvantages of the fossil record?

A
  • some fossils are still undiscovered
  • many organisms decompose before they have a chance to fossilise
  • some fossils have been destroyed by volcanoes/ earthquakes
  • conditions needed for fossils to form are not often present
23
Q

what is natural selection?

A

the process by which organisms best suited to their environment survive and reproduce, passing on their characteristics to their offspring through their genes

24
Q

how does natural selection occur?

A
  1. organisms within a species show variation in characteristics caused by genetic variation - new alleles can arise by mutation
  2. organisms with characteristics best suited to a selection pressure have a greater chance of surviving and successfully reproducing
  3. less well adapted organisms die or fail to reproduce
  4. successful organisms pass allele encoding advantageous characteristic onto their offspring
  5. process repeated over every generation. over time allele increases in frequency in gene pool
25
Q

what is intraspecific variation?

A

differences between organisms within a species

26
Q

what is interspecific variation?

A

variation between members of different species

27
Q

what are the causes of variation?

A
  • genetic variation

- environmental variation

28
Q

what causes genetic variation?

A
  • alleles
  • mutations
  • meiosis - independent assortment and crossing over
  • sexual reproduction - alleles inherited from both parents
  • chance - different gametes are produced and combine
29
Q

why is there more variation in organisms that reproduce sexually than asexually?

A

asexual reproduction results in the production of clones genetically identical to parent. genetic variation can only be increased as a result of mutation

30
Q

what causes environmental variation?

A
  • disease
  • accident
  • sunlight
  • diet
31
Q

what is discontinuous variation?

A

a characteristic that can only result in certain discrete values
it is controlled by a single gene

32
Q

how is discontinuous variation represented graphically?

A

using a bar chart or pie chart

33
Q

what is continuous variation?

A

a characteristic that can take any value within a range
controlled by a number of genes
often influenced by environmental factors

34
Q

how is continuous variation represented graphically?

A

data from a frequency table is plotted on a histogram

35
Q

what are the characteristics of a normal distribution?

A
  • the mean, mode and median are the same
  • distribution has a bell shape symmetrical about the mean
  • 50% of values are below mean and 50% are above the mean
  • most values lie close to the mean
36
Q

what is normal distribution?

A

a distribution of continuous data

forms a bell-shaped curve

37
Q

what is standard deviation?

A

measure of how spread out the data is
the greater the standard deviation is, the greater the spread of data
68% of values are within 1 standard deviation of the mean in the normal distribution

38
Q

what is Student’s t test?

A

statistical test used to compare the mean values of two sets of data

39
Q

what is Spearman’s rank correlation coefficient?

A

a specific type of correlation test that compares the ranked orders of two datasets in order to consider their relationships

40
Q

what are adaptations?

A

characteristics that increase an organism’s chance of survival and reproduction in its environment

41
Q

what are anatomical adaptations?

A

physical features (internal and external)

42
Q

what are some examples of anatomical adaptations?

A
  • body coverings - hair, scales, spines, feathers for warmth, flight, protection
  • camouflage - blend in with environment to protect from predators
  • teeth - related to diet
  • mimicry - copying a dangerous animal’s appearance to trick predators
    anatomical adaptations provide evidence for convergent evolution
43
Q

what is an analogous structure?

A

structures that have adapted to perform the same function but have different genetic origin
convergent evolution - organisms evolve similarities because the organisms adapt to similar environments and similar selection pressures

44
Q

what are behavioural adaptations?

A

the way an organism acts - can be inherited or learnt

45
Q

what are some examples of behavioural adaptations?

A
  • survival behaviours (playing dead)
  • courtship to attract a mate
  • seasonal behaviours - migration or hibernation
46
Q

what are physiological adaptations?

A

processes that take place inside an organism

47
Q

what are some examples of physiological adaptations?

A
  • poison production - to kill prey or to protect against being eaten
  • antibiotic production
  • water holding
  • reflexes
  • temperature regulation
48
Q

what is convergent evolution?

A

organisms evolve similarities because the organisms adapt to similar environments or selection pressures

49
Q

what are homologous structures?

A

structure that appears superficially different in different organisms but has the same underlying structure

50
Q

what is divergent evolution?

A

species evolved from a common ancestor, with a different set of adaptive features for a new habitat as a result of migration or loss of habitat

biology (25 decks)

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