4.3 Classification and evolution Flashcards

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1
Q

why do we classify organisms

A
  • more convenient
  • to make the study of living things more manageable
  • to make it easier to identify organisms
  • to help see the relationships between species
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2
Q

what are organisms classified into

A
domain
kingdom
phylum
class
order
family
genus
species
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3
Q

what are the 3 domains

A

archaea
eubacteria
eukaryote

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4
Q

what are the 6 kingdoms

A
archaebacteria
eubacteria
plants
animals
fungi
protoctists
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5
Q

how are organisms sorted into the phylum category

A

organisms which have the same body plan (possession of backbone)

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6
Q

how are organisms sorted into the class category

A

possess same general traits (no. of legs)

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7
Q

how are organisms sorted into the order category

A

subdivision of class (omnivore, herbivore, carnivore)

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8
Q

how are organisms sorted into the family category

A

group of closely related genera

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9
Q

how are organisms sorted into the genus category

A

group of closely related species

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10
Q

how are organisms sorted into the species category

A

basic unit of classification- sorted by variation

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11
Q

describe the binomial naming system

A
  • used to name organisms
  • genus (capital letter) and species (lowercase) name are used
  • must be underlined
  • in latin so its universal
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12
Q

why does using a common name for organisms not work well

A
  • different countries call organisms differently
  • some organisms may have different common names in diff parts of a country
  • translation of languages may give different names
  • same common name may be used for different species in different parts of the world
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13
Q

define the biological definition of species

A

a group of organisms that can freely interbreed to produce fertile offspring

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14
Q

define the phlylogenetic definition of a species

A

a group of individual organisms that are very similar in appearance, anatomy, physiology, biochemistry and genetics

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15
Q

describe the features of archaea and eubacteria

A
  • no nucleus
  • have loop of DNA
  • naked DNA
  • no membrane bound organelles
  • smaller ribosomes
  • smaller cells than eukaryotes
  • may be free living or parasitic
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16
Q

describe the features of protoctists

A
  • eukaryotic
  • mostly single-celled
  • show wide variety of forms
  • show various animal/plant-like features
  • mostly free living
  • have autotrophic or heterotrophic nutrition
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17
Q

define autotrophic and heterotrophic

A

auto- can photosynthesise

hetero- can break down large molecules

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18
Q

describe the features of fungi

A
  • eukaryotic
  • exist as single cells or have mycelium that consist of hyphae
  • walls made of chitin
  • cytoplasm is multinucleate
  • mostly free living and saprophytic(cause decay or organic matter)
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19
Q

describe the features of plants

A
  • eukaryotic
  • multicellular
  • cells surrounded by cellulose cell wall
  • autotrophic
  • contain chlorophyll
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20
Q

describe the features of animals

A
  • eukaryotic
  • mulyicellular
  • heterotrophic
  • usually able to move around
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21
Q

what did Linnaeus use to classify organisms

A

observable features

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22
Q

what can we now use to classify organisms

A
biological molecules (cytochrome C)
DNA
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23
Q

how can we use cytochrome C to classify organisms

A

-its a protein found in respiration
-not identical in all species
If we compare the sequence of amino acids in cytochrome C of 2 species:
=sequences the same, must be closely related
=sequences different, not closely related
=the more differences in sequence, the less closely related

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24
Q

how can we use DNA to classify organisms

A

found in all organisms and provides genetic code-instructions for producing proteins
comparison of DNA sequences can determine how closely 2 species are related

25
Q

how are eubacteria different to archaea and eukaryote

A
  • eubacteria have different cell membrane structure
  • different enzymes for synthesising RNA
  • different mechanisms for DNA replication and synthesising RNA
26
Q

what features do archaea share with eukaryotes

A
  • similar enzymes for synthesising RNA
  • similar mechanisms for DNA replication and synthesising RNA
  • production of some proteins that bind to their DNA
27
Q

define phylogeny

A

the study of the evolutionary relationship between organisms

28
Q

describe artificial classification

A

classification done for convenience (easy to remember or to find)

  • based on only a few characteristics
  • does not reflect evolutionary relationships
  • provides limited info
  • is stable
29
Q

describe natural classification

A

organised into hierarchy

  • uses many characterises
  • reflects evolutionary relationships
  • provides lots of useful info
  • may change with advancing knowledge
30
Q

define common ancestor

A

when a species is an ancestor of two or more species later in time
they do not survive today (extinct)

31
Q

define monophyletic

A

group of organisms that descended from a common ancestor

32
Q

define classification

A

process of sorting things into groups

33
Q

define natural selection

A

the term used to explain how features of the environment apply a selective force on the reproduction of individuals in a population

proposed by Charles darwin- Galapagos island- finches had different beaks to consume different foods

34
Q

what evidence do we have for natural selection

A

fossil evidence

biological molecules

35
Q

how does fossil evidence show natural selection

A
  • old species have died out and new one have arisen
  • new species that appeared are often similar to old ones in the same place
  • many similarities between living and fossil species
  • modern species had variations-better adapted to environment
  • fossil species were larger than modern species
36
Q

how do biological molecules show natural selection

A
  • certain molecules suggest that all species arose from one original ancestor
  • closely related species separated recently
  • species that are less related have more differences in biological molecules
  • cytochrome c
  • structure of DNA
37
Q

describe the process of natural selection

A
  • variation occurs because of mutation
  • there is a selection pressure
  • organisms that are best adapted to the environment survive, they have advantageous alleles, others die
  • they reproduce and pass on alleles to offspring
  • over time, can lead to new species
38
Q

define selection pressure

A

competition for food, space, water, sunlight (climate change or something running out, use of antibiotics/pesticides)

39
Q

why is genetic variation important for evolution

A

variation due to environmental factors will not pass on to offspring

40
Q

what does a mutation cause

A

a bacterium/insect to develop resistance to a particular antibiotic/pesticide which causes variation in the population

41
Q

how can resistance occur in bacteria

A

overuse of antibiotics, misusing them (not taking a full course), using them on live stock

42
Q

how did pesticides cause an endangered species

A
  • pesticide used on crops
  • resulted in resistance to DDT in insects due to natural selection
  • small birds ate insects and this built up the food chain-more concentrated
  • perigrine falcons couldn’t lay eggs- too fragile and shattered
  • became endangered species
43
Q

define variation

A

the presence of variety-differences between individuals

44
Q

define intraspecific variation

A

variation between members of the same species

45
Q

define interspecific variation

A

differences between species

46
Q

define discontinuous variation

A

where there are distinct categories and nothing in between

47
Q

examples of discontinuous variation

A

gender
some bacteria have flagella others don’t
human blood groups
whether you can roll your tongue
It is monogenetic (controlled by one gene)

48
Q

defame continuous variation

A

variation where there are two extremes and a full range in between

49
Q

examples of continuous variation

A

-height in humans
-length of leaves on oak tree
-length of stalk of a toadstool
-number of flagella on bacteria
-body mass
-intelligence
this variation is polygenetic (controlled by a variety of genes)

50
Q

when would you use standard deviation and how would you interpret it

A

to measure the amount of variation or spread from the mean
low standard deviation indicates narrow range and greater reliability
high standard deviation indicates large range and lower reliability

51
Q

when would you use the T test and how do you interpret it

A
test used to compare two means
null hypothesis- no significant difference between the means of 2 sets
we have to accept or reject
if our value is lower, accept
if our value is higher, reject
52
Q

when would you use spearman’s rank correlation

A

used to consider the relationship between two sets of data
tells whether two sets of data are correlated
lower value than critical value=no relationship=accept null hypothesis

53
Q

define adaptation

A

a characteristic that enhances survival in the habitat

54
Q

what will a well adapted organisms be able to do

A
  • find enough food + water
  • gather enough nutrients
  • defend itself from predators and disease
  • survive physical conditions of its environment
  • respond to changes in the environment
  • have sufficient energy to allow successful reproduction
55
Q

define convergent evolution

A

the process whereby organisms not closely related independently evolve similar traits as a result of being adapted to similar environments

56
Q

what is marram grass

A

specialised plant adapted to living on sand dunes where there is little water available

57
Q

anatomical adaptations of marram grass

A
  • long roots which spread over wide area- reach deep underground and absorb water
  • leaves are curled, lower epidermis covered in hair and folded to create pits- reduces air movement and loss of water vapour
  • low density of stomata, leaf covered in thick waxy cuticle- reduces evaporation of water from cells
58
Q

behavioural adaptations of marram grass

A

responds to shortage of water by rolling leaf tight and closing stomata
when covered by sand, it will grow to reach sunlight

59
Q

physiological/ biochemical adaptations of marram grass

A
  • ability to roll leaf- tighter when less water available
  • guard cells open and close stomata
  • not salt tolerant so maintains water potential lower than other plants