Species etc Flashcards
What is a species? (2)
- Group of similar organisms / organisms with similar features / / organisms with same genes/chromosomes2. that reproduce to produce fertile offspring
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 species2. Fewer habitats/niches3. Decrease in variety of food / fewer food sources4. Aspect of clearing forest (killing insects) eg machinery, pesticides
Organisms can be classified using a hierarchy of phylogenetic groups. Explain what is meant by:1. a hierarchy2. a phylogenetic group
- Groups within groups 2. No overlap (between groups)2. (Grouped according to) evolutionary links/history/relationships / common ancestry;
What is intraspecific variation?
Variation / differences within the same/a species
There are ethical and economic arguments for maintaining biodiversity. Suggest one ethical argument for maintaining biodiversity and one ECONOMIC argument for doing so.
(We should maintain biodiversity to)1. Prevent extinction /loss of populations 2.reduction in populations /loss of habitats 3. save organisms for future generationsECONOMICA 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
Give two ways in which courtship increases the probability of successful mating.
- Attracts/recognises same species2. Attracts/recognises mate/opposite sex3. Indication of sexual maturity/ fertility / synchronises mating4. Stimulates release of gametes5. Form pair bond
Frequent treatment with the antibiotic vancomycin can result in resistant strains of bacteria. Explain how.
- Mutation present/occurs2. Resistance gene/allele3. Resistant bacteria (survive and) reproduce4. Vertical (gene) transmission / Horizontal (gene) transmission / conjugation
The gene for resistance to vancomycin is very common in the bacterium Enterococcus faecalis. The same gene has now been found in the bacterium Staphylococcus aureus.Use your knowledge of gene transmission to explain how the gene was passed from one species of bacterium to another.
- Horizontal (gene) transmission2. Via conjugation/pilus3. Plasmid/Gene/DNA replicated/copied4. Plasmid transferred (to S.aureus)
Scientists can use protein structure to investigate the evolutionary relationships between different species. Explain why.
- Amino acid sequences / primary structure2. Closer the (amino acid) sequence the closer the relationship3. (Protein structure) related to (DNA) base/triplet sequence
Comparing the base sequence of genes provides more evolutionary information than comparing the structure of proteins. Explain why.
- Reference to base triplets/triplet code / more bases than amino acids / longer base sequence than amino acid sequence2. Introns / non-coding DNA3. of code / more than one code for each amino acid
Explain what is meant by genetic diversity.
Difference in DNA/base sequence / difference in alleles/genes/gene pool
Apart from genetic factors what other type of factor causes variation within a species?
Environmental
The spotted owl is a bird. Numbers of spotted owls have decreased over the past 50 years. Explain how this decrease may affect genetic diversity.
Reduced (genetic diversity)As fewer different/varied alleles/genes / reduced gene poo(Genetic) bottleneck
Costa Rica is a Central American country. It has a high level of species diversity.There are over 12 000 species of plants in Costa Rica. Explain how this has resulted in a high species diversity of animals. (2)
Greater variety / different foodsMore habitats/niches
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 speciesSome species may be present in low/high numbers
An order is a taxonomic group. Fruit flies and mosquitoes belong to the same order of insects. Name the other three taxonomic groups to which fruit flies and mosquitoes both belong.
Kingdomphylum and class
Explain what is meant by a phylogenetic relationship.
Shows evolutionary relationship
What information is required to calculate an index of diversity for a particular community?
Number of a / each species