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A Level Biology > Topic 3.1 Classification > Flashcards

Topic 3.1 Classification Flashcards

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1
Q

Define classification

A

The process of naming and organising organisms into groups based on their characteristics

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2
Q

Name the 8 groups in the classification hierarchy, from largest to smallest

A
  • domain
  • kingdom
  • phylum
  • class
  • order
  • family
  • genus
  • species
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3
Q

Define species

A

a group of organisms that can interbreed to form fertile offspring

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4
Q

Give a limitation of the reproductive species model

A

Doesn’t account for species that reproduce asexually

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5
Q

Why can it be difficult to assign organisms to one species?

A
  • species often change both morphologically and genetically overtime
  • how ‘similar’ do two organisms need to be to be classed as the same species
  • hybrids- classed as new species or not
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6
Q

How can we analyse evolutionary relationships genetically?

A
  1. DNA sequences
  2. Gel electrophoresis
  3. Bioinformatics
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7
Q

How does gel electrophoresis work?

A
  • agar gel in a tray with wells where the DNA fragments go
  • apply an electrical current
  • the fluorescent DNA fragments are slightly negatively charged
  • move towards the anode and the smaller fragments travel further
  • creates a DNA profile with bands of amino acids
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8
Q

How does DNA sequencing work?

A
  • DNA broken into small fragments
  • terminated at different lengths using fluorescently marked nucleotides, then duplicated using PCR
  • fragments undergo gel electrophoresis, with the smallest fragments travelling further
  • can read the base sequence of the fragment according to distance travelled
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9
Q

What is bioinformatics?

A

the use of technology and software to analyse large amount of biological data. can compare entire genomes and look for where mutations have caused divergence in the phylogenetic tree

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10
Q

How does the scientific community evaluate data?

A
  • papers sent out to expert for peer review to check for validity
  • if data and conclusion seem reasonable, results are published in scientific journals
  • may also be presented at conferences
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11
Q

Why has the 5 kingdom model of classification come under scrutiny?

A
  • relies heavily on physical observations

- since the introduction of DNA sequencing, new models have been developed

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12
Q

Why is the 3 domain model of classification more accepted by the scientific community?

A

takes into account research of a particular ribosomal unit and more accurately represents evolutionary relationships than 5 kingdom

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13
Q

What is taxonomy?

A

the science of describing, classifying and naming living organisms

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14
Q

Define evolution

A

the process by which natural selection acts on variation to bring about adaptations and eventually speciation

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15
Q

Define biodiversity

A

biodiversity is a measure of the variety of living organisms and their genetic differences

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16
Q

What are domains?

A

the 3 largest classification groups, including Eukaryota, Bacteria and Archaea

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17
Q

What kingdom does Archaea contain?

A

one kingdom: archaebacteria

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18
Q

What kingdom does the bacteria domain contain?

A

Eubacteria

19
Q

What are the 4 eukaryotic kingdoms?

A

protoctista, fungi, plantae, animalia

20
Q

Describe archaebacteria

A

ancient bacteria, thought to be found only in extreme conditions but now found in more places e.g. soil

21
Q

Describe eubacteria

A

‘true bacteria’ for example bacteria that causes disease and are useful in our digestive system

22
Q

Describe the 4 eukaryotic families (protoctista, fungi, plantae, animalia)

A

protoctista- microscopic, some are heterotrophs (have to eat other organisms) and some autotrophs (make their own food by photosynthesis) e.g. amoeda, chlamydomonas
fungi- all heterotrophs, most are saprophytic and some parasitic, they have chitin, not cellulose in their cell walls
plantae- basically all autotrophs
animalia- all heterotrophs that move their whole bodies around during at least one stage of their lifecycles. including invertebrates and vertebrates

23
Q

What is morphology?

A

the study of form and structure of organisms

24
Q

What are analogous features?

A

features that look similar or have a similar function but are not from the same biological origin

25
Q

What are homologous features?

A

structures that genuinely show common ancestry

26
Q

What is a genus?

A

a group of species that all share common characteristics

27
Q

What is the ecological species model?

A

based on the ecological niche occupied by an organism, not robust because niche definitions vary and an organism can occupy multiple niches

28
Q

Define the mate-recognition species model

A

based on unique fertilisation systems, including mating behaviour, although many species mate or cross pollinate with other species

29
Q

What is the genetic species model?

A

based on DNA evidence

30
Q

Define the evolutionary species model

A

based on shared evolution relationships between groups of organisms

31
Q

Name the limitations of species models

A
  1. finding evidence
  2. interbreeding to form fertile hybrids
  3. many organism don’t reproduce sexually
  4. fossil organisms can’t reproduce
32
Q

What is the morphological species model?

A

based solely on the appearance of the organisms observed

33
Q

Define sexual dimorphism

A

where there is a great deal of difference between the appearance of the male and female of a species

34
Q

What is molecular phylogeny?

A

the analysis of the genetic material of organisms to establish their evolutionary relationships

35
Q

Define DNA sequencing

A

the process by which the base sequences of all or part of the genome of an organism is worked out

36
Q

What is DNA profiling?

A

the process by which the non-coding areas of DNA are analysed to identify patterns

37
Q

What is bioinformatics

A

the development of software and computing tools needed to organise and analyse raw biological data

38
Q

What is an endosymbiont?

A

an organism that lives inside the cells or the body of another organism

39
Q

What is the monera?

A

a kingdom in the five-kingdom classification system that contains the archaea and eubacteria

40
Q

What is the protoctista?

A

a kingdom that contains all single-celled organisms

41
Q

Define extremophiles

A

bacteria that can survive extreme conditions of heat, cold, pH, salinity and pressure

42
Q

What are heterotrophs?

A

organisms that cannot make their own food

43
Q

What are autotrophs?

A

organisms that can make their own food, either by photosynthesis or chemosynthesis

44
Q

Define electrophoresis

A

a method of separating fragments of proteins or nucleic based on their electrical charge and size

A Level Biology (32 decks)

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