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OCR A level Biology > 4.2.2 Classification and evolution > Flashcards

4.2.2 Classification and evolution Flashcards

1
Q

how many different organisms do scientists believe currently exist on earth?

A

8.7 billion

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2
Q

what are classification systems?

A

the process by which living things are sorted into groups

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3
Q

what does it mean when organisms are in the same group in the classification system?

A

they share similar characteristics

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4
Q

what is phylogeny?

A

this is the study of how closely related species are, look at evolutionary relationships

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5
Q

what is taxonomy?

A

the study of the principles behind classification (this uses differences and similarities and put them into groups)

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6
Q

why do we classify things?

A

-to identify species
-to predict characteristics
-to find evolutionary links

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7
Q

how is this single classification system utilised world wide?

A

by using a single classification system worldwide, scientists can identify links between different organisms even if they live on different continents

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8
Q

what are the seven taxonomic groups in the Linnean classification system?

A

Kingdom
Phylum
Class
Order
Family
Genus
Species

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9
Q

what happens as you move down the hierarchy of the taxonomic groups in the Linnean classification system?

A

as you move down the hierarchy there are more groups but fewer organisms in each group- the organisms in each group become more similar and share more of the same characteristics

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10
Q

describe the species taxon

A

-smallest unit of classification
-same physiology, anatomy, morphology and behaviour

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11
Q

define species

A

a species is a group of organisms that are able to reproduce fertile offspring

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12
Q

what is binomial nomenclature?

A

all species are given a name consisting of two parts

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13
Q

what is the first word of binomial nomenclature?

A

-the organisms genus
-must start with a capital letter

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14
Q

what is the second word of binomial nomenclature?

A

-the organisms species
-must start with a small letter

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15
Q

what form must the words in binomial nomenclature be in?

A

they should all be in italics and if handwritten then underlined

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16
Q

which taxon includes the most specific characteristics?

A

species

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17
Q

which taxon includes the broadest characteristics?

A

kingdom

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18
Q

which taxon includes more species, an order or a family?

A

order

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19
Q

which taxon includes only organisms that can successfully interbreed?

A

species

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20
Q

if two organisms belong to the same family, what other taxonomic groups do the organisms have in common?

A

order, class, phylum, kingdom

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21
Q

how many kingdoms are there?

A

5

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22
Q

how many kingdoms did there used to be?

A

two (plants and animals)

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23
Q

why did two kingdoms become five?

A
  • as technology improved so did scientific knowledge
    -this allowed plants to be separated into more kingdoms
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24
Q

what are the different feeding systems?

A

-autotrophic
-heterotrophic
-saprotrophic

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25
Q

define autotrophic

A

an organism that transforms inorganic molecules into organic molecules (photosynthesis)

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26
Q

define heterotrophic

A

an organisms that has to eat and digest other organisms to gain organic molecules

27
Q

define saprotrophic

A

organisms that release extra-cellular enzymes and absorb nutrients

28
Q

what are some examples of fungi?

A

-mushrooms
-yeast
-mould

29
Q

what are some examples of prokaryotes?

A

-bacteria
-blue green algae

30
Q

what are some examples of protoctists?

A

-paramecium

31
Q

what are the kingdoms?

A

-animals
-plants
-fungi
-prokaryotes
-protoctists

32
Q

what are the characteristics of animals?

A

-are eukaryotes
-are multicellular
-have heterotrophic nutrition
-have fertilised eggs that develop into a ball of cells called a blastula
-are usually able to move around

33
Q

what are the characteristics of plants?

A

-are eukaryotes
-are multicellular
-have cells surrounded by a cellulose cell wall
-produce multicellular embryos from fertilised eggs
-have autotrophic nutrition

34
Q

what are the characteristics of fungi?

A

-reproduce by spores
-are eukaryotes
-have a mycelium which consists of hyphae (made up of long threads)
-have walls made of chitin
-have cytoplasm that is multinucleate
-are mostly free living and saprophytic, they cause the decay or organic matter
-never have cilia or flagella

35
Q

what are the characteristics of prokaryotes?

A

-have no nucleus
-have a loop of naked DNA (DNA that is not associated with histone proteins) that is not arranged in linear chromosomes
-have no membrane bound organelles
-have smaller ribosomes than in other groups
-carry out respiration not in mitochondria, but on special membrane systems (mesosomes)
-have cells smaller than those of eukaryotes
-exist as single cells or small groups of cells
-cell wall contains peptidoglycon
-no visible feeding mechanisms, nutrients are absorbed through cell wall

36
Q

what were prokaryotes called before?

A

Monera

37
Q

what are the types of prokaryotes?

A

-archea
-bacteria

38
Q

why was the kingdom protoctists made?

A

they can’t be categorised into the other kingdoms

39
Q

what are the characteristics of protoctists?

A

-are eukaryotes
-are mostly single celled
-show a wide variety of forms]-show various plant like and animal like features
-are mostly free living
-have autotrophic or heterotrophic nutrition, some photosynthesise, some ingest prey, some feed using extracellular enzymes and some are parasites

40
Q

what are the ways monerans can get their food energy?

A

-saprotrophic
-parasitism
-mutualism

41
Q

what was early classification like?

A

-based on observable characteristics (morphology and anatomy)
-similarities in behaviour (live or move in water/air)

42
Q

what are some advances in technology that have helped improve classification systems?

A

-light microscope
-electron microscope
-physiology
-biochemistry

43
Q

what is used now to classify organisms?

A

-DNA
-physiology and morphology
-biochemistry

44
Q

how is DNA used in classification?

A

-the % similar DNA shows how close the evolutionary relationship is
-the higher the percentage the more closely related in evolution the organisms are and the lower the percentage the less closely related they are

45
Q

how is biochemistry used in classification?

A

the more similar the protein amino acid sequence, the more closely related the organisms are in evolution and vice versa

46
Q

what is the name of the common protein used in comparing amino acid sequences for classification?

A

cytochrome C

47
Q

what is cytochrome C?

A

a protein used in respiration, therefore, in all living organisms

48
Q

why is cytochrome C used in classification?

A

amino acid sequence is different in different organisms

49
Q

how is cytochrome C used in classification?

A

-more similar = more closely related
-less similar = less closely related

50
Q

what did Carl Woese suggest a new classification system based on?

A

-rRNA nucleotide sequences in eukaryotes and prokaryotes
-lipid structure and antibody sensitivity

51
Q

what did Carl Woese suggest about prokaryotes due to his new classification system?

A

decided prokaryotes had 2 distinct groups based on molecular structure and metabolic pathway

52
Q

what are the different domains?

A

-eukaryotes
-archaeae
-bacteria (eubacteria)

53
Q

how many ribosomes do eukaryotes have?

A

80S ribosomes

54
Q

how many ribosomes do archaeae have?

A

70S ribosomes

55
Q

how many ribosomes do bacteria have?

A

70S ribosomes

56
Q

how many proteins does eukaryotes RNA polymerase have?

A

has 12 proteins

57
Q

how many proteins does archaeae RNA polymerase have?

A

has 8-10 proteins

58
Q

how many proteins does bacteria RNA polymerase have?

A

has 5 proteins

59
Q

what is phylogeny?

A

means the evolutionary history of a species

60
Q

what is cladistics?

A

a biological system of classification based on phylogeny

61
Q

what happens as groups of organisms evolve from common ancestors?

A

they keep some of the same traits

62
Q

what does a cladogram gram show?

A

shows how those traits diverge between species

63
Q

what does it mean the closer 2 organisms are in a cladogram?

A

the more probable that they are closely related by evolution

64
Q

draw an evolutionary tree to demonstrate the domains

A

see paper flashcard

OCR A level Biology (4 decks)

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