Biodiversity, Species & Taxonomy Flashcards
Define Biodiversity
The number of species and the number of individuals of each of the species within any one community.
Define Species Richness
The number of different species in a community.
Define community (1)
All the individuals of all the species living together in the same area at the same time.
Define Species (1)
A group of similar organisms (with same genes) which reproduce to produce fertile offspring.
Define Genetic Diversity
Difference in DNA/base sequence/alleles/genes
Define Niche
An organism’s role in the ecosystem/community -
No 2 species occupy the same niche due to interspecific competition.
It describes:
What the species is like
Where it occurs
How it behaves
How it interacts with other species
How it responds to the environment.
Define Habitat
A place where an organism normally lives within an ecosystem (characterised by biotic & abiotic factors)
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 (2)
- Measures number of individuals in a species/different proportions of species;
- Some species may be present in low/high numbers.
Give two advantages of using an index of biodiversity rather than an indicator species.
- You don’t need to identify each species;
- The index considers the number of organisms of each of the species.
Suggest one economic argument for maintaining biodiversity.
A suitable example of how some species may be important financially
Examples:
1. Medical / pharmaceutical uses;
2. Commercial products / example given;
3. Tourism;
4. Agriculture;
5. Saving local forest communities.
Why are ecosystems with a high diversity index stable?
- Consists of many organisms/greater range of species;
- so loss (through disease or climate change) does not severely affect the ecosystem.
(Favourable climate)
Explain selection (6)
- Variation due to mutation;
- Different environmental/ abiotic/biotic conditions / selection pressures;
- Selection for different/ advantageous, features/ characteristics/mutation/ /allele;
- Differential reproductive success / (selected) organisms survive and reproduce;
- Leads to change in allele frequency;
- Occurs over a long period of time
The number of species present is one way to measure diversity.
Explain why an index of diversity may be a more useful measure of biodiversity (2)
Also measures number of individuals (in species);
Some species may be present in high/low numbers
Give 2 advantages of using an Index of Biodiversity rather than an Indicator Species (2)
• You do not need to identify each species;
• The index considers the number of organisms of each of the species.
A forest was cleared to make more towns 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 sources;
- Aspect of clearing forest (killing insects) e.g
- Machinery
- Pesticides & herbicides
- Fertilisers (for monoculture - 1crop)
What information is required to calculate an index of diversity for a particular community? (2)
• Number of species;
• Number of individuals in each species
Farmers clear tropical forest and grow crops instead. Explain how this causes the diversity of insects in the area to decrease (4)
- Lower diversity of plants / fewer plant species;
- Few food sources/feeding sites;
- Few habitats/niches;
- Fewer herbivore species so fewer carnivores;
- Aspect of agriculture (killing insects) e.g Machinery, pesticides
Describe the binomial naming system (1)
Scientific name:
Genus - Homo
Species - sapien
Describe the classification system (1)
Organisms are placed into taxa (groups) based on their shared characteristics
What are the three domains?
(And their differences)
• Bacteria
- single-celled prokaryotes, murein cell wall, no histones
• Archaea
- triglycerides are joined by ether bonds, not ester, no murein in in cell walls
• Eukarya
What four kingdoms does the Eukarya domain make up?
Protists
Fungi
Plantae
Animalia
Define the order of classification.
D - Domain
K - Kingdom
P - Phylum
C - Class
O - Order
F - Family
G - Genus
Species
Name the taxonomy group between order and genus (1)
Family
Describe what is meant by a phylogenetic group (1)
Groups according to (shared) common ancestry
- More/less closely related
Describe what is meant by a hierarchy (1)
Groups within groups with no overlap
Describe courtship behaviour between two similarly related organisms (1)
Courtship behaviour attracts a mate to ensure REPRODUCTIVE SUCCESS
Closely related organisms display similar behaviour patterns.
Give an example of species specific courtship behaviour
• Fireflies give off pulses of light
• Peacock display their feathers
• Male butterflies release chemicals
Give two ways in which courtship increases the probability of successful mating (5!)
- Attracts same species;
- Attracts opposite sex;
- Indication of sexual maturity/Synchronises mating/fertility;
- Stimulates release of gametes;
- Form pair bond.
Give two ways scientists can use base sequences to compare different types of ____ (organism/species)
- Compare DNA base sequence;
- Compare mRNA base sequence (proteins/antibodies);
- Look for mutations
Comparing the base sequence of genes provides more evolutionary information than comparing the structure of proteins. Explain why (3)
- Base triplets of DNA longer than amino acid sequence;
- Introns in DNA
- Degenerate code - same amino acid may be coded for
Why do scientists use genetic classification methods to classify species? (2)
• More similar genome/DNA base sequence means more closely related species;
• Unable to observe reproductive behaviour of extinct organisms /asexual / ethical issues
Describe how comparisons of biological molecules in two species could be used to find out if they are closely related (2)
Any two from:
1. Compare DNA;
2. Sequence of bases/nucleotides;
3. Compare antibodies;
4. Compare sequence of amino acids/primary structure
During an experiment, scientists placed traps to collect dung beetles at sites chosen at random. Explain why at random (1)
No bias
(Reliable)
Give two reasons why grassy strips increase the biodiversity of animals (2)
- Increase in niche/habitat;
- Increase in food source (e.g herbivores) so increase in predator species
List 3+ ways that modern farming has negatively impacted the biodiversity of the countryside.
(Reduces species richness)
- Removal of woodland
- Removal of hedgerows
- Growing monoculture
- Intensive grazing / plagioclimax
- Overuse of pesticides / inorganic fertilisers
