biodiversity, taxes & classification Flashcards
What is a species?
- Group of similar organisms / organisms with similar features / / organisms with same genes / chromosomes;
- Reproduce to produce fertile offspring;
Explain what is meant by a heirarchy
- Groups within groups;
- 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 / traits / 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.
1. medical / pharmaceutical uses;
2. commercial products / example given;
3. tourism;
4. agriculture;
5. saving local forest communities;
Farmers clear tropical forest and grow crops instead. Explain how this causes the
diversity of insects in the area to decrease.
- Lower diversity of plants/ few species of plants/less variety of plants/few plant layers;
- Few sources/types of food/feeding sites;
- Few habitats/ niches;
- Fewer (species of) herbivore so few (species of) carnivores;
- Aspect of agriculture (killing insects);
Describe how courtship behaviour increases the probability of successful mating.
- Attracts/recognises same species;
- Attracts/recognises mate/opposite sex;
- Indication of sexual maturity/ fertility / synchronises mating;
- Stimulates release of gametes;
- Form pair bond;
What is meant by biodiversity? (1)
number of individuals of each species within the community
What is meant by a community? (1)
ALL individuals of ALL species living together in the same area at the same time
Explain what is meant by a niche (2)
- An organisms role in the community / ecosystem
- How organisms interact with other species and responds to the environment
How to calculate diversity index?
(N(n -1))/sum of n (n-1)
N = total number of organisms of ALL species
n = total number of organisms of EACH species
What information is required to calculate an index of diversity for a particular community? (2)
- Number of species
- Number of individuals of each species
List the order of the hierarchy.
Start with the largest group.
- Domain
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
Give two ways doctors could use base sequences to compare different types of HPV (3)
- Compare DNA base sequence
- Compare mRNA base sequence
- Look for mutations
