10.1 - Species and taxonomy Flashcards

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1
Q

what is classification

A
  • The organisation of living organisms into groups
  • it IS NOT a random process, but based on a number of accepted principles
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2
Q

what is a species

A

basic unit of classification

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3
Q

what do members of a single species all have in common

A
  • they are capable of breeding to produce living, fertile offspring
    –> therefore when a species reproduces sexually, any of the genes of its individuals can, in theory, be combined with any other
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4
Q

who came up with the binomial system

A

Swedish botanist Linnaeus

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5
Q

describe how animals are identified with the binomial system

A

Given 2 names

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6
Q

describe the 2 names given in the binomial system

A
  • it’s a universal system based on Latin/Greek names
  • the first name (generic name), denotes the genus which the organism belongs.
  • the second name (specific name), denotes the species which and organism belongs. It is never shared by other species within the genus.
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7
Q

describe the rules for the binomial system

A
  • the names are printed in italics, but if they’re handwritten = underlined. This is to indicate that they’re scientific names
  • the fist letter of the generic name is upper case, but the first letter of the specific name is lower case
  • if the specific name is unkown, you can just write ‘sp’, e.g ‘Felix sp.’
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8
Q

Because members of the same species have the same genes, what does this mean?

A
  • resemble each other physically and biochemically
  • this is the same for their behaviour, which has evolved along with their own genes
  • this evolved behaviour is courtship and helps with ensuring mating
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9
Q

how does courtship behaviour help to achieve reproduction

A

enables individuals to:
- recognise members of their own species (ensures that mating only occurs with members of the same species, so that offspring are fertile)
- identify a mate that is capable of breeding (because both partners need to be sexually mature, fertile and receptive to mating)
- form a pair bond (that will lead to successful mating and raising of offspring)
- 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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10
Q

describe courtship behaviour for females

A
  • they undergo a cycle of sexual activity in which they can only conceive during a very short time
  • they are only receptive to mating for a period around the time when they produce eggs
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11
Q

describe courtship behaviour for males

A
  • used to determine whether the female is at a receptive stage
  • if she responds with the appropriate behavioural response, courtship continues and is likely to result in the production of offspring
  • is she isn’t receptive, she exhibits a different pattern of behaviour and the male ceases to court her, turning his attention elsewhere.
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12
Q

how are members of the same species able to recognise each other for courtship

A
  • animals use signals to communicate with a potential mate and with members of their own sex
  • typically there is a chain of actions between male and female
  • this chain of actions is the same for all members of the same species. And therefore varies between species
  • this allows individuals to recognise if their partner is of the same species or not
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13
Q

what is classification

A

the grouping of organisms

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14
Q

what is taxonomy

A

the theory and practise of biological classification

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15
Q

what are the 2 main forms of classification

A
  • artificial classification
  • phylogenetic classification
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16
Q

what is artificial classification

A
  • it divides organisms according to differences that are useful at the time
  • such features may include: colour, size, no. of legs, leaf shape, etc
  • these are described as analogous characteristics where they have the same function but don’t have the same evolutionary origins (e.g. wings on butterflies and birds)
17
Q

what is phylogenetic classification

A
  • is based upon the evolutionary relationships between organisms and their ancestors
    -classifies species into groups using shared features derived from their ancestors
  • Arranges the groups into a hierarchy, in which the groups are contained within larger composite groups with no overlap
18
Q

what are relationships in a phylogenetic classification based on

A
  • homologous characteristics
  • HCs have similar evolutionary origins regardless of their functions in the adult of a species
19
Q

what is each group within a phylogenetic biological classification called

A

taxon (plural: taxa)

20
Q

what is taxonomy

A
  • the study of taxa and their position in a hierarchical order, where they are known as taxonomic ranks
  • these are based upon the evolutionary line of descent of the group members
21
Q

what is the highest taxonomic rank (what is this rank made up of)

A
  • Domain (made up of 3)
    1) Bacteria
    2) Archaea
    3) Eukarya
22
Q

what are bacteria

A

group of single-celled prokaryotes

23
Q

what are the features of bacteria

A
  • the absence of membrane-bounded organelles such as nuclei or mitochondria
  • unicellular, although cells may occur in chains or clusters
  • ribosomes are smaller (70S) than in eukaryotic cells
  • cell walls are present and made of murein (never chitin or cellulose)
  • single loop of naked DNA made up of nucleic acids but no histones
24
Q

what are Archaea

A

a group of single-celled prokaryotes that were originally classified as bacteria which they resemble in appearance

25
Q

what are the features of Archaea that makes them differ from bacteria

A
  • their genes and protein synthesis are more similar to eukaryotes (they contain introns)
  • their membranes contain fatty acid chains attached to glycerol by ether linkages
  • there is no murein in their cell walls
  • they have a more complex form of RNA polymerase (to deal with the introns)
26
Q

what are Eukarya

A

a group of organisms made up of 1 or more eukaryotic cells

27
Q

what are the features of Eukarya

A
  • their cells possess membrane-bound organelles such as mitochondria and chloroplasts
  • they have membranes containing fatty acid chains attached to glycerol by ester linkages
  • not all possess cells with a cell wall, but where they do it contains no murein
  • ribosomes are larger (80S) than in bacteria and archaea
28
Q

what are the 4 kingdoms that the Eukarya domain is divided into

A
  • Protoctista
  • Fungi
  • Plantae
  • Animalia
29
Q

what are the different taxonomic ranks

A
  • Domain
  • Kingdom
  • phylum
  • class
  • order
  • family
  • genus
  • species
30
Q

what is the phylogeny of an organism

A

it reflects the evolutionary branch that led up to it (its evolutionary line of descent)

31
Q

how is the phylogenetic relationships of different species usually represented

A
  • a tree-like diagram called:
  • a phylogenetic tree
  • in these diagrams: the oldest species is at the base of the tree, and the most recent ones are represented by the ends of the branches
32
Q

why might there be difficulty in defining a species

A
  • species are not fixed, but change and evolve over time. In time, some individuals may develop into a new species
  • within a species there can be considerable variation among individuals. All dogs, for example, belong to the same species, but artificial selection has led to a variety of different breeds
  • Many species are extinct and most of these have left no fossil record
  • some species rarely, if ever, produce sexually
  • members of different populations of the same species may be isolated, e.g. oceans, so never got the chance to meet and therefore never got the chance to interbreed
  • some types of organism are sterile