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AQA A level Biology > Species, Taxonomy > Flashcards

Species, Taxonomy Flashcards

1
Q

Organisms of the same species can…

A

Breed to produce fertile living offspring

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2
Q

Binomial naming system

A

First name = denotes genus (eg. Vibrio)

Second name = denotes species (eg. fischeri)

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3
Q

How would you name something if you know the genus but not the species? Eg. Vibrio …

A

Vibrio sp.

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4
Q

Why is it important that mating is successful and offspring have a maximum chance of survival?

A

Often females only produce eggs at specific times even only once a year so need to make sure this mating is successful and offspring survive

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5
Q

What does courtship behaviour enable individuals to do? (5)

A

Recognise members of their own species - to endure mating take spaces between mementos of the same species so they can produce living fertile offspring

Identify a mate that is capable of breeding - because both species need to be sexually mature, fertile and receptive to mating

Form a pair bond - that will lead to successful mating and raising of offspring

Synchronise mating - so that it takes place when there is maximum probability of the sperm and egg meeting

Become able to breed - by bringing a member of the opposite sex into a physiological state that allows breeding to occur

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6
Q

Talk about males determining the receptive stage of females

A

Females undergo cycle of sexual activity where they can only conceive for a short period of time. They are often only receptive to mating in this period so courtship behaviour is used by males to determine whether females are in this receptive stage.

Responding with appropriate behavioural response = courtoisie continues and offspring occur

If not makes focus on another female

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7
Q

Talk about the special signals and communications between potential mates

A

Courtship animals use signals and behaviour to communicate with a potential mate.

This allows both individuals to recognise their partner is of the same species and so they are prepared to mate. Typically there is a chain of actions between the male and female. This chain of actions will stay the same for all members of a species but différent species have different chains of action etc.

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8
Q

Define classification

A

The grouping of organisms

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9
Q

Define taxonomy (and what it involves)

A

The theory and practice of biological classification of life which involves naming organisms and sorting them into groups (that do not overlap)

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10
Q

Two main forms of biological classification?

A

Artificial

Phylogenetic

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11
Q

Artificial classification

A

Groups organisms according to observed features. IRRESPECTIVE OF EVOLUTIONARY ORGANISMS.

Eg. Size, colour, number of legs

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12
Q

Analogous characteristics

A

Same function or appearance but different evolutionary origin

(Eg. Bat, bird and insect wing)

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13
Q

Phylogenetic (natural) classification

definition + (three things)

A

Phylogenetic classification is a system that attempts to arrange species into groups based on their evolutionary origins and relationships.

  • based upon the evolutionary relationships between organisms and their ancestors
  • classifies species into groups using shared features derived from their ancestors
  • arranges groups into a hierarchy where there are groups within groups but no overlap
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14
Q

Homologous characteristics

A

Characteristics which have similar evolutionary origins regardless of their function

(Eg. Sing of bird, arm of human, leg of horse all have same evolutionary origin)

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15
Q

Three main domains

A

Bacteria
Archaea
Eukarya

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16
Q

Bacteria characteristics

A
  • single celled prokaryote
  • NO membrane bound organelles
  • unicellular
  • 70S ribosomes
  • cell walls present and made of murein (never chitin or cellulose)
  • circular DNA NO HISTONES
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17
Q

Archea characteristics

A
  • single celled prokaryotes

They differ from bacteria because:

  • genes and protein synthesis more similar to eukaryotes
  • membranes contain fatty acid chains attached to glycerol by ether linkages
  • no murein in their cell walls
  • have a more complex form of RNA polymerase
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18
Q

What were archaea originally classified as?

A

Bacteria due to similar appearance

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19
Q

Eukarya characteristics

A

Organisms made up of one or more eukaryotic cells

  • YES membrane bound organelles
  • have membranes containing fatty acid chains linked to glycerol by ESTER linkages
  • not all have cell walls (when they do it is made of murein)
  • ribosomes 80S
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20
Q

What domain are the 4 kingdoms part of?

A

Eukarya

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21
Q

Name the 4 kingdoms of eukarya

A

Protoctista
Fungi
Plantae
Animalia

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22
Q

State the 7 taxonomic ranks

A 
Kingdom 
Phylum
Class
Order
Family
Genus
Species
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23
Q

Define Phylogeny

A

Study of evolutionary relationships and origins between organisms

(Who’s related to who and how closely are they related)

PHYLOGENY IS TAKEN INTO ACCOUNT WHEN SORTING INTO GROUPS AND CLASSIFYING ORGANISMS

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24
Q

Phylogenetic trees represent …

A

Phylogenetic relationships of different species

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25
Q

First branch point of a phylogenetic tree is the

A

Common ancestor (now extinct)

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26
Q

How to tell closely related species in a phylogenetic tree

A

They have diverged away from each other more recently (don’t have to look as far back to see branching point)

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27
Q

When sorting organisms into groups, scientist take…

A

Phylogeny into account and group organisms according to their evolutionary relationships

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28
Q

How many levels of groups are used to classify organisms ?

What are all these groups called together and what are they called separately?

A

8

Taxa

Taxon

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29
Q

What makes the taxa a hierarchy?

A

The largest group is at the top (domain)

And the smallest is at the bottom (species)

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30
Q

What do we mean when we say there is no overlap of organisms in the taxa?

A

Organisms can only belong to one group at each level in a hierarchy

XXXX

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31
Q

What happens as you move down the hierarchy (8 taxons)?

A

More groups at each level (what does this actually mean???) - more orders at each level ???

But less organisms in each group Although the organisms in each group are more CLOSELY RELATED

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32
Q

Define species

A

A group of similar organisms that are able to reproduce to give fertile offspring

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33
Q

What naming system is used in classification?

A

The binomial naming system

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34
Q

How can courtship behaviour be used to classify organisms?

A

Closely related species have more similar courtship behaviour

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35
Q

How could you deceive courtship behaviour?

A

Species specific

Only members of the same species will do and respond to courtship behaviour. This allows members of the same species to recognise each other so that reproduction can be more successful and fertile offspring can be produced.

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36
Q

3 example of courtship behaviour

A

Male peacocks showing off colourful tails
Fireflies give off pulses of light
Butterflies release chemicals

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37
Q

Why are the offspring from two different species mating infertile?

ASK HARV

A

The offspring will have an odd number of chromosomes so meiosis cannot occur so no gametes can be produced.

Eh. Horse has 64 chromosome, mule has 62 chromosomes, horse gamete has 32 chromosomes, donkey gamete has 31 chromosomes when these fuse the zygote has 63 chromosomes

38
Q

What are branch points on a phylogenetic tree called? What do they represent ?

A

Nodes

Common ancestors of the species that come after the branch point (node)

39
Q

What do nodes typically represent?

A

Populations

40
Q

What do branch tips typically represent?

A

A group of related organisms or taxons

41
Q

Define a clade

A

A group of species that share a single common ancestor

Imagine clipping a horizontally to cut a branch off the tree, the branches that would fall off are part of the clade

42
Q

Complicated sentence about branch tips, nodes and descendants that I can never remember.

A

All branch tips arising from a given node are descendent from the common ancestor of that node

43
Q

Talk briefly about phylogenetic trees VS a cladogram

Three things - interchangeable, ancestral, hypothesis

A

Many biologists use the term interchangeably

Both based on ancestral relationships

Some scientists associate phylogenetic trees with true evolutionary history and cladograms as representing a hypothesis about a group of organisms ancestry

44
Q

Define taxa

A

A series of groups arranged into a hierarchy

45
Q

Which method of classification is more useful to a biologist and why?

A

Phylogenetic

It isn’t subjective

46
Q

What is phylogenetic grouping?

A

Grouping organisms based on evolutionary origins and relationships into hierarchy groups within groups that do not overlap (smaller groups placed within larger groups)

47
Q

Why did people originally think archaea were NOT a separate kingdom?

A

Often completely resemble bacteria so were originally classified as bacteria

In 1977 archaea was made it’s own kingdom. Phylogeny increasingly based on DNA and RNA sequencing and they found archaea and bacteria have different genes. Archaea genes of anything are more similar to eukarya genes.

Carl Woese (American microbiologist) coined ‘archebacteria’ —-> ‘ARCHAEA’

48
Q

How do archaea and bacteria differ?

A

Archaea genes and protein synthesis is more similar to eukarya than bacteria

Archaea have membranes containing fatty acids attached to glycerol by ETHER linkages whereas bacteria have water linkages.

49
Q

Define biodiversity

A

The number and variety of living organisms, species and habitats in a particular area

50
Q

Species diversity

A

Number of different species and the number of individuals of each species within any one community

51
Q

Genetic diversity

A

Variety of genes and alleles possessed by all of the individuals that make up a population of a species

52
Q

Ecosystem diversity

A

Range of different habitats

53
Q

What is species richness?

A

(A measure of species diversity)

The number of different species in a particular area at a given time.

54
Q

Talk about differing proportions of species in a meadow and field even if overall they have the same number of different species (eg. Both have 25 different species)

A

Field and meadow may both have 25 different species

But the field may have 95% of the indivises are the same species and the last 5% are the other 24 species

Meadow there are equal amount of individuals of each species

55
Q

How can we measure species diversity?

A

d = N(N-1)/ sum of n(n-1)

d = index of diversity

N = total number of organisms of all species

n = total number of organisms of each species

56
Q

What is the index of diversity equation?

A

d = N(N-1)/ sum of n(n-1)

57
Q

In the index of diversity equation what does a higher value of d mean?

A

The greater the species diversity

58
Q

Why is it more useful to calculate a species index of diversity than to just record the number of species present?

A

X

Provides a singular number that makes it easier to compare variety in habitats ?

59
Q

What does Simpson’s diversity of index take into account?

A

The number of species present

And

Abundance of each species

60
Q

What does a high species diversity index often mean for an ecosystem?

A

The more stable it is and less affected by change for example climate change

61
Q

Why are ecosystems with a high species diversity index usually more stable in changing conditions?

A

If there is a drought a community with a high species diversity index is much more likely to have at least one species that is able to tolerate the drought (ie. it might have a mutation). So some membres are likely to survive and maintain the community

62
Q

Why is an ecosystem usually like in extreme conditions? What are communities dominated by?

A

In extreme environments only a few species have the necessary adaptions to survive so there is a lower species diversity index.

This means the ecosystem is less stable

Also the communities are dominated by climatic factors rather than by the organisms in the community.

63
Q

What is species diversity of index like in less hostile environments?

A

Usually quite high

64
Q

Why is an ecosystem usually like in less hostile conditions? What are communities dominated by?

A

Stable ecosystem

Communities dominated by living organisms rather than the climate

65
Q

Benefits of a high species diversity?

XXX

A

Stable ecosystem

Each species less likely to become extinct (due to high genetic diversity) WHY ??

If a species does become extinct it will not affect the food chain as there are other species available

66
Q

4 ways deforestation lowers species diversity ?

A

1) decreases plant species diversity
2) less variety of habitats
3) less variety of food sources
4) decreases animal species diversity

67
Q

4 things done in agriculture/farming that lower species diversity?

A

1) deforestation to make space for farms lower plant species diversity
2) selectively breeding animals or plants reduces diversity
3) using pesticides to kill other species
4) only growing a few species of plant or only keeping a few animal species

68
Q

How was genetic diversity originally measured?

A

By observing the characteristics of organisms

Method based on fact that each observable characteristic is determined by a gene

69
Q

Limitation of measuring genetic diversity by looking at observable characteristics?

XXXX don’t get page 248 of ketboodle

A

Lots of characteristics are polygenic

70
Q

Four techniques of clarifying evolutionary relationships

A

Genome sequencing (DNA bases)

Comparing Amino acid sequences

Immunological comparisons

Comparing base sequence of mRNA

71
Q

How can GENOME SEQUENCING be used to detect evolutionary relationships and if organisms are closely related?

A

Entire base sequence of an organisms DNA can be determined and then compared to the DNA base sequence of another organism

Closely relegated species will have a higher percentage similarity in the order of bases

72
Q

How can AMINO ACID SEQUENCING be used to detect evolutionary relationships and if organisms are closely related?

A

Base sequence of DNA is found and then the sequence of amino acids is worked out

Closely related species will have similar amino acid sequences

73
Q

How can immunological comparisons be used to detect evolutionary relationships and if organisms are closely related?

A

Proteins (eg. Antigens) that are very similar will bind to the same antibodies

If antibodies for a human version of a protein are added to an isolated sample of proteins from another species, of the antibodies bind and recognise the protein then the human protein and protein from the other species must be very similar

74
Q

How were early estimates of genetic diversity taken?

A

Looking at the frequency of observable characteristics

Since different alleles determine a different characteristic, lots of different characteristics within a population suggested many different alleles and so high genetic diversity

75
Q

How have gene technologies allowed us to measure genetic diversity directly?

(Comparing DNA base sequences)

A

Comparing DNA base sequences of the same gene in different organisms in a population allows scientist to see if there are any differences in base sequences and hence identify how many alleles of that gene there are in the population.

76
Q

How have gene technologies allowed us to measure genetic diversity directly?

(Comparing mRNA base sequences)

A

Different alleles produce slightly different mRNA base sequences and may produce proteins with slightly different amino acid sequences which could also be compared.

77
Q

How do computers compare DNA sequences?

A

Each base can be tagged with a fluorescent dye

This produces a series of coloured bands

The pattern and order of colours is scanned by lasers so that the base sequences of different organisms can be compared

78
Q

How can the base sequence of mRNA be used to see if organisms are closely related?

A

the bases sequence of the mRNA is complimentary to the DNA base sequence.

Compare the mRNA base sequence and closely related organisms have similar order of bases on the mRNA

79
Q

Describe the technique of immunological comparisons

A

Gist: antibodies specific to antigen are made, injected into a different species, of species has similar antigens on the protein these antibodies will bind to this species version of the protein as well, precipitate = closely relatedness

Albumin (a protein with antigens) from species A is injected into species B

Species B makes antibodies specific to the albumin in antigens

Serum with antibodies made by species B is extracted and mixed with blood from species C

Species C contains albumin with antigens as well so if it is a similar protein (with similar antigens) the antibodies produced by species B will bind and form a precipitate.

Greater number of similar antigens = more precipitate = more closely related species are

80
Q

Describe 4 agricultural practices that have DIRECTLY removed habitats and reduced species diversity.

A

1) removal of hedgerows and grubbing out of woodland
2) creating monocultures (growing a single crop)
3) filling in ponds, drainage marsh and other wetland
4) overgrazing of land - prevents regeneration of woodland (and from succession?)

81
Q

Describe three agricultural practices that have had an INDIRECT effect on reducing habitats and species diversity

A

1) use of pesticides and inorganic fertilisers
2) escape of effluent from silage stores and slurry tanks into water courses
3) absence of crop rotation, intercropping or undersowing

82
Q

Crop rotation

A

Practice of growing different species of crops in the same area across a sequence of growing seasons

83
Q

Undersowing

A

To sow a crop with or after a main crop so that it can grow on after the main crop has been harvested

84
Q

Intercropping

A

Growing two or more crops in a field simultaneously

(Aim is to produce greater yield on given price of land by making use of resources which otherwise wouldn’t be used if only a single crop was being grown)

85
Q

9 conservation techniques to increase and maintain species and habitat diversity

A

1) plant hedges rather than fences as field boundaries
2) maintain existing ponds
3) leave wet corners of fields rather than draining them
4) reduce use of pesticides (use biological control instead)
5) use organic rather than inorganic fertilisers
6) use crop rotation that includes nitrogen fixing crops that can improve soil fertility rather than soil fertilisers
7) use intercropping rather than herbicides to control weeds
8) leave curing edges of field until after flowering when seeds have dispersed
9) introduce conservation headlands - areas at the edge of fields where pesticides are used restrictives so wild flowers/insects can breed.

86
Q

Explain how farmers selecting particular crops to grow leads to a reduction in species diversity.

A

Farmer’s select species with particular qualities to grow

The genetic variety of alleles is reduced to the few alleles for these specific qualities

If most of the area is taken up by the one species the farmer is growing, there is less area and resources for other species. Other species do not survive this competition.

Overall effect is reduction in species diversity

87
Q

What is the main causes of decrease in species diversity?

A

Clearance of land in order to grow crops to meet human demand for food

88
Q

Benefits of hedge rows

A

Increase species diversity
Produce food
Animals can live in hedge rows
Provide bordering of fields for farmers

89
Q

Species diversity

A

Number of species in a community and abundance of each species

90
Q

What is Simpson diversity index of all individuals are the same species?

A

1

91
Q

Name 5 agricultural practices (CGP) that reduce biodiversity.

A

1) woodland clearance reduced number of trees and species of trees. Destroys habitats and species lose food source and shelter. Species will die or be forced to migrate to another suitable area
2) hedgerow removal - (done to increase farmland by turning lots of snap fields into fewer large fields). Reduced biodiversity but ridding species of hedgerow, habitats, food resource and shelter.
3) Pesticides - reduces diversity by directly killing pests but any species that feed on the pests lose a food source and are also reduced
4) herbicides - reduces plant diversity and the species that feed on weeds
5) monoculture - reduces biodiversity directly as only one single species allowed to grow. Supports fewer organisms, loss of food resource and shelter of plan species that can no longer grow

92
Q

Examples of conservation schemes (3)

A

1) giving legal protection to endangered species
2) create protected areas such as )SSSIs and AONB to destroy further development
3) environmental stewardship scheme encourages farmers to conserve biodiversity (eg. By replanting hedgerows or leaving margins around fields for wild flowers to grow)

AQA A level Biology (36 decks)

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