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biology - component 2 > classification and biodiversity > Flashcards

classification and biodiversity Flashcards

1
Q

define phylogenetics

A

the study of evolutionary history and relationships among organism.
can be represented as a tree

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2
Q

define classification

A

the placing of organisms into groups, which are divided up into progressively smaller groups

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3
Q

define hierarchy

A

a system of ranking in which small groups are nested components of larger groups

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4
Q

define taxonomy

A

the identification and naming of organisms

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5
Q

define domain

A

the largest taxon, split into 3 groupings (Bacteria and Archaea which are prokaryotes, and Eukaryotes)

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6
Q

define kingdom

A

the second largest grouping, consisting of Prokaryota, Protoctista, Fungi, Animalia, Plantae

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7
Q

define phylum

A

a subgroup of a kingdom, defined by body plan

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8
Q

define class

A

a subgroup of phylum combining taxa with a distinct level of complexity (e.g mammalia)

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9
Q

define order

A

subgroup of a class

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10
Q

define family

A

a group within an order, for a group of genera. humans are part of the Hominidiae, along with great apes reflecting our recent evolutionary divergence

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11
Q

define genus

A

a group of similar organisms - we are homo sapiens, and shared the genus with

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12
Q

define species

A

a group of phenotypically similar organisms capable of interbreeding to produce fertile offspring

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13
Q

define homologous structures

A

structure with different functions, but a similar form and developmental origin indicating a more recent common ancestor

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14
Q

define divergent evolution

A

when evolution from a common ancestral structure gives rise to structures that perform many different functions

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15
Q

define analogous structures

A

structures that perform the same function and have a similar shape, but have different developmental origins

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16
Q

define convergent evolution

A

when evolution gives rise to structures with similar properties but different developmental origins

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17
Q

define biodiversity

A

the number of species (species richness) and the number of individuals within each species (species evenness) in a specified region

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18
Q

define polymorphism

A

the term used to describe the presence of several different forms or types of individuals among the members of a single species, resulting form a given gene having multiple alleles (e.g eye colour can be blue, green, brown)

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19
Q

how does a phylogenetic tree work?

A
  • the further up the diagram you go, the further forward in time
  • the species at the top are all species that exist now
  • the shorter branches are species that are extinct
  • the points at which the branches join highlight common ancestors
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20
Q

what is the hierarchy of biological classification?

A

domain
kingdom
phylum
class
order
family
genus
species

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21
Q

are taxa discrete or continuous, and what does this mean?

A

discrete
at any level of classification, an organism belongs in one taxon and no other

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22
Q

why do we need a classification system?

A
  • it allows us to infer evolutionary relationships. if two organisms are in the same taxon, we infer that they are more closely related
  • if a new animal is discovered with a beak and feathers, we predict some of its other characteristics based on our general understanding of birds
  • it improves scientific communication. e.g. it is easier to say ‘bird’ than a complicated phrase
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23
Q

what are domains defined based on?

A

originally defined on rRNA base sequences but more modern methods consider similarities in DNA base sequences

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24
Q

what are the three domains?

A
  1. bacteria (eubacteria)
  2. archaea (archaeabacteria)
  3. eukaryota
25
Q

describe eubacteria

A

true bacteria such as E.coli and salmonella

26
Q

describe archaeabacteria

A
  • extremophile bacteria
  • exist in a wide variety of environmental conditions including extremes of temperature, pH, salinity and pressure
27
Q

describe eukaryota

A

all eukaryotic organisms - plants, animals, fungi, protoctista

28
Q

what are the 5 different kingdoms?

A
  1. prokaryota
  2. protoctista
  3. fungi
  4. animalia
  5. plantae
29
Q

describe prokaryota

A
  • microscopic organisms
  • all bacteria and cyanobacteria (blue-green algae)
30
Q

describe protoctista

A
  • mainly single celled
  • lack tissue differentiation
  • examples include: plankton, spirogyra, amoeba
31
Q

describe fungi

A
  • cell wall made from chitin
  • can reproduce asexually or sexually
  • sexual reproduction produces spores and enables the fungus to adapt to a changing environment
  • examples include: yeast (single celled), moulds such as penicillium and mushroom
32
Q

describe animalia

A
  • multicellular organisms with nervous coordination
  • no cell wall
  • 35 animal phyla, these all include a great range of body plans e.g annelida, arthropoda and chordata
33
Q

describe plantae

A
  • multicellular organisms that photosynthesise
  • have a cellulose cell wall
  • examples include: mosses, ferns, conifers, angiosperms
34
Q

what does taxonomy allow us to do?

A
  • discover and describe biological diversity
  • investigate evolutionary relationships between organisms
  • classify organisms to reflect their evolutionary relationships
35
Q

advantages of binomial naming system?

A
  • unambiguous naming
  • based on latin so can be used all over the world
  • implies that two species sharing part of their name are closely related e.g Panthera leo and Panthera tigris
36
Q

why do biochemical methods reduce the mistakes made in classification due to convergent evolution?

A
  • two organisms may have analogous structures
  • biochemical methods can confirm if these organisms are closely related or if structures are derived from a different origin
37
Q

how can the relatedness of organisms be assessed?

A

biochemical methods such as DNA ‘genetic fingerprinting’ and enzyme studies

38
Q

outline how biochemical methods are used to assess the relatedness of organisms

A
  • biochemical methods are used to measure the proportion of DNA or proteins shared between species and use this information to estimate relatedness
  • the more shared DNA or proteins (such as enzymes), the more closely related the organisms
  • DNA fragments usually separated by gel electrophoresis ; compare position and width of bands
39
Q

what are the three main reasons for biodiversity changing?

A
  1. succession
  2. natural selection
  3. human influence
40
Q

describe succession as a reason for biodiversity changing

A

the change in species composition over time
as succession occurs animal biodiversity increases but plant biodiversity decreases

41
Q

describe natural selection as a reason for biodiversity changing

A

the gradual process by which inherited characteristics become more or less common within a population, in response to changes in the environment

42
Q

describe human influence as a reason for biodiversity changing

A

this has made many environments in the world less hospitable to living organisms
- it has decreases their biodiversity and often led to extinction

43
Q

human activities which are reducing biodiversity?

A
  • habitat destruction through deforestation
  • over hunting
  • introduction of new species
44
Q

how is biodiversity used to support human civilisation?

A
  • a small number of plant species provide the staple food e.g wheat and rice for humans worldwide
  • medicinal drugs are derived from plants and animals e.g for heart disease and antibiotics
  • living organisms provide important raw materials e.g rubber and cotton
45
Q

what is a biodiversity index used for?

A

used to monitor the biodiversity of a habitat over time and compare biodiversity in different habitats

46
Q

describe the simpsons diversity index

A
  • allows us to calculate the diversity of a habitat, such as invertebrates in a stream
  • the calculation gives you a numerical value and the higher the value, the higher the biodiversity
47
Q

how can you assess biodiversity at a genetic level?

A

looking at the variety of alleles in the gene pool of a population.
- this can be done by studying the proportion of polymorphic loci across the genome

48
Q

what does polymorphism result from?

A

presence of polymorphic genes
i.e. multiple alleles for the same gene

49
Q

how can genetic biodiversity be assessed?

A
  • number of alleles at a locus
  • proportion of the population that have a particular allele
50
Q

describe how the number of alleles at a locus links to genetic biodiversity

A

the more alleles present at a locus the greater biodiversity and the more polymorphism shown by this gene

51
Q

describe how the proportion of alleles links to genetic biodiversity

A
  • if 98% of all the alleles for a particular gene are the same recessive allele, there is low biodiversity for that gene
  • if only 50% of the alleles in the gene pool were recessive, 50% would be the other alleles, so the biodiversity for that gene would be higher
52
Q

how can biodiversity at a molecular level be assessed?

A

DNA fingerprinting

53
Q

describe DNA fingerprinting as a way to assess biodiversity at a molecular level

A
  • as it is very difficult to count every single allele in a population researches collect samples of DNA and analyse the base sequences to look for variations between individuals
  • researches can use DNA fingerprinting and sequencing to compare the DNA base sequences of different organisms in a population
  • the greater the variation in the DNA base sequence, the greater the genetic diversity of the population
54
Q

describe how the results would differ if there was a change in genetic diversity (gel electrophoresis)

A

more genetically diverse: less similar bands with different widths and positions
less genetically diverse: more similar bands with same widths and positions

55
Q

define natural selection

A

gradual process in which characteristics become more or less common within a population, in response to the environment determining the breeding success of individuals

56
Q

outline the process of natural selection

A
  • mutations occur within the DNA of individuals
  • variation produced within population
  • some individuals have a selective advantage and are better suited to competing within that particular environment
  • these individuals therefore survive - survival of the fittest - and reproduce, passing the alleles with the selective advantage onto their offspring
57
Q

describe anatomical traits

A
  • animals that live in deserts have to cope with extreme temperature fluctuations and a limited availability of water
  • different organisms have different adaptations to overcome the same problem
58
Q

describe physiological traits

A

mammals and birds are endothermic and use a lot of energy maintaining their body temperature.
- they must therefore avoid wasting too much energy maintaining their body temperature in the cold

59
Q

describe behavioural traits

A
  • desert animals such as Kangaroo rats and lizards, live in burrows which do not get too hot or too cold and have more humid air inside. these animals stay in their burrows during the hot days and emerge at night to feed
  • courtship in animals include the displaying of peacock tails or the elaborate dances performed by birds such as flamingos ; these increase an animal’s chance of mating

biology - component 2 (7 decks)

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