Biodiversity, species and taxonomy Flashcards

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1
Q

What is a species?

A
  1. Group of similar organisms / organisms with similar features / / organisms with same genes / chromosomes;
  2. Reproduce to produce fertile offspring;
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2
Q

Explain what is meant by a heirarchy

A
  1. Groups within groups;
  2. No overlap (between groups);
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3
Q

Explain what is meant by a phylogenetic group

A

(Grouped according to) evolutionary links/history/relationships / common ancestry;

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4
Q

Explain what is meant by genetic
diversity.

A

Difference in DNA/base sequence/alleles/genes;

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5
Q

The number of species present is one way to measure biodiversity. Explain why an
index of diversity may be a more useful measure of biodiversity

A

Also measures number of individuals in a species / different proportions of species;
Some species may be present in low/high numbers;

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6
Q

What is meant by species richness

A

The number of different species in a community

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7
Q

Explain how natural selection produces changes within a species.

A
  1. Variation [caused by mutation] between members of population / species;
  2. Predation / disease / competition results in differential survival;
  3. Some have adaptations that favour survival;
  4. Differential reproductive success / survive to reproduce/ have more offspring/
  5. Pass on their advantageous alleles /
  6. Changes allelic frequencies
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8
Q

Describe how comparisons of biological molecules in two species could be used to find out if they are closely related.

A

Genetic variation:
Compare DNA base sequence;
Compare RNA base sequence;
Compare sequence of amino acids /primary structure (of named / same protein);

DNA hybridisation by separating DNA strands / break hydrogen bonds;
Mix DNA/strands (of different species);
Temperature/heat required to separate (hybrid) strands indicates relationship;

Immunological evidence – not a mark
Inject (seahorse) protein/serum into animal;
(Obtain) antibodies/serum;
Add protein/serum/plasma from other (seahorse) species;
Amount of precipitate indicates relationship;

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9
Q

In classification, comparing the base sequence of a gene provides more information than comparing the amino acid sequence for which the gene codes. Explain why.

A
  • Reference to base triplet/triplet code / more bases than amino acids / longer base sequence than amino acid sequence;
  • Introns/non-coding DNA;
  • Same amino acid may be coded for / DNA code is degenerate;
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10
Q

Scientists’ analysis of blood proteins has indicated a lack of genetic diversity in populations of some organisms.

Describe the processes that lead to a reduction in the genetic diversity of populations of organisms. (6)

A
  1. Mark for general principle of - reduced variety/number of different alleles/DNA / reduced gene pool (in new population);
  2. Founder effect;
  3. A few individuals from a population become isolated/form colonies:
  4. (Genetic) bottlenecks;
  5. (Significant) fall in size of population
  6. Selective breeding / artificial selection;
  7. Using organisms with particular alleles / traits / phenotypes / characteristics
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11
Q

Scientists can use protein structure to investigate the evolutionary relationships
between different species.

Explain why.

A
  1. Amino acid sequences / primary structure;
  2. Closer the (amino acid) sequence the closer the relationship;
  3. (Protein structure) related to (DNA) base/triplet sequence;
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12
Q

A forest was cleared to make more land available for agriculture.
After the forest was cleared the species diversity of insects in the area decreased.
Explain why. (4)

A
  1. Decrease in variety of plants / fewer plant species;
  2. Fewer habitats/niches;
  3. Decrease in variety of food / fewer food sources;
  4. Aspect of clearing forest (killing insects) eg machinery, pesticides;
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13
Q

What is meant by a genetic bottleneck.

A
  1. Sudden decrease in population / many killed by an event eg earthquake;
  2. Idea of reduced/low genetic variation/diversity / reduction in (variety of) alleles / smaller gene pool;
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14
Q

Suggest one ethical argument for maintaining biodiversity.

A

Prevent extinction /loss of populations/ reduction in populations /loss of habitats / save organisms for future generations (idea of);

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15
Q

Suggest one economic argument for maintaining biodiversity.

A

A suitable example of how some species may be important financially e.g.
1. medical / pharmaceutical uses;
2. commercial products / example given;
3. tourism;
4. agriculture;
5. saving local forest communities;

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16
Q

Farmers clear tropical forest and grow crops instead. Explain how this causes the
diversity of insects in the area to decrease.

A
  1. Lower diversity of plants/ few species of plants/less variety of plants/few plant layers;
  2. Few sources/types of food/feeding sites;
  3. Few habitats/ niches;
  4. Fewer (species of) herbivore so few (species of) carnivores;
  5. Aspect of agriculture (killing insects);
17
Q

Describe how courtship behaviour increases the probability of successful mating.

A
  1. Attracts/recognises same species;
  2. Attracts/recognises mate/opposite sex;
  3. Indication of sexual maturity/ fertility / synchronises mating;
  4. Stimulates release of gametes;
  5. Form pair bond;
18
Q

Describe how organisms are grouped in a phylogenetic classification system

A
  1. Hierarchy of groups with no overlaps
    OR smaller groups within larger groups with no overlaps
  2. grouped according to evolutionary origins/relationships/history