Biodiversity, Taxonomy & Classification Flashcards
What is a species?
- Group of similar organisms/organisms with same genes
2. Reproduce to produce fertile offspring
Explain what is meant by a hierarchy.
- Groups within groups
2. No overlap (between groups)
Explain what is meant by a phylogenetic group.
(Grouped according to) evolutionary links/history/relationships/common ancestry
Explain what is meant by genetic diversity.
Difference in DNA/base sequence/alleles/genes
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.
- Also measures number of individuals in a species/different proportions of species
- Some species may be present in low/high numbers
What is meant by species richness.
The number of different species in a community.
Explain how natural selection produces changes within a species.
- Variation caused by mutation between members of population/species
- Predation/disease/competition results in differential survival
- Some have adaptations that favour survival
- Differential reproductive success/survive to reproduce/have more offspring
- Pass on their advantageous alleles
- Changes allelic frequencies
Describe how comparisons of biological molecules in two species could be used to find out if they are closely related.
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
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.
- 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
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)
- Mark for general principle of - reduced variety/number of different alleles/DNA/reduced gene pool (in new population)
- Founder effect
- A few individuals from a population become isolated/form colonies
- (Genetic) bottlenecks
- (Significant) fall in size of population
- Selective breeding/artificial selection
- Using organisms with particular alleles/phenotypes/characteristics
Scientists can use protein structure to investigate the evolutionary relationships
between different species.
Explain why.
- Amino acid sequences/primary structure
- Closer the (amino acid) sequence the closer the relationship
- (Protein structure) related to (DNA) base/triplet sequence
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)
- Decrease in variety of plants/fewer plant species
- Fewer habitats/niches
- Decrease in variety of food/fewer food sources
- Aspect of clearing forest (killing insects) eg machinery, pesticides
What is meant by a genetic bottleneck.
- Sudden decrease in population/many killed by an event eg earthquake
- Idea of reduced/low genetic variation/diversity/reduction in (variety of) alleles/smaller gene pool
Suggest one ethical argument for maintaining biodiversity.
- Prevent extinction
- Loss of populations
- Reduction in populations
- Loss of habitats
- Save organisms for future generations (idea of)
Suggest one economic argument for maintaining biodiversity.
A suitable example of how some species may be important financially e.g.
- Medical/pharmaceutical uses
- Commercial products/example given
- Tourism
- Agriculture
- Saving local forest communities
