10. BIODIVERSITY Flashcards
What is biodiversity?
Biodiversity is thevarietyof plant and animal life in aparticular habitat.
Name the three types of diversity in nature
Genetic, species and ecosystem
Define what a habitat is
A place where a community of organisms live.
Define what a community is
An interacting group oforganismsin a habitat.
Define what an ecosystem is
A biological community ofinteracting organismsand theirphysical environment.
Define species richness
The number of speciesin a habitat.
Why does increasing the variety of plants in an ecosystem increase the biodiversity?
The number of different habitats increases, and the variety of different food sources increases
Recall the equation to calculate Index of Diversity
Recall the two things you need to be able to calculate Index of Diversity
The total number of organisms, and the abundance of each organism
Why is it better to use Index of Div instead of species richness?
Species richness only measure the number of species, whereas the index of diversity measure the species richness and abundance of each
What happens to the value of the Index of Div as the ecosystem becomes more biodiverse?
It increases
What happens the stability of an ecosystem and its ability to withstand change as its biodiversity changes?
It increases
What effect does farming have on the species richness of an ecosystem?
It decreases it
What effect does farming have on the index of diversity of an ecosystem?
It decreases it
How does crop farming create a lower biodiversity of animals?
It reduces the number of different habitats, and reduces the variety of food sources
Name four artificial interventions used by farmers to reduce the competition for their crops
Pesticides, herbicides, fertilisers, irrigation
How do farmers eliminate unwanted plants?
Herbicides
How do farmers eliminate unwanted animals?
Pesticides
What should farmers use instead of fences to separate their fields?
Hedgerows
Why should farmers maintain any ponds on their land?
Ponds would increase the number of different habitats, and increase the variety of different food sources
Describe the effect of overgrazing on the biodiversity of the ecosystem
It decreases it
Why might farmers replace hedgerows with fences?
Fences increase the area available to grow crops, and fences require less maintenance SO more income
Why is crop rotation important in crop farming?
It prevents soil becoming deficient in one particular mineral
Why should farmers wait to cut the edges of fields until after flowering and seed dispersal?
To allows natural pollination and seed dispersal to maintain the biodiversity of the natural plants
Why is using observable characteristics to determine evolutionary relationships not always accurate?
Most observable characteristics are polygenic. Observable characteristics can be changed by the environment. Structures can be analogous.
Which process changes the base sequence of DNA?
Mutation
Which three biological molecules can you use to determine two individuals / species relatedness?
DNA, mRNA and proteins
How do you determine how closely related two individuals are by using their DNA base sequences?
Count the number of differences / similarities
What happens over time that causes more physical differences to exist between different individuals / species?
Mutations accumulate over time, and the more genetic differences, the more physical differences
Which biological molecule is the most inaccurate to use to ascertain evolutionary relatedness?
Proteins
Why are proteins the most inaccurate biological molecules to use to ascertain evolutionary relationships?
Each aminoacid is coded for by a tripletofbases. Each amino acid can be coded for by more than one codon because DNA is degenerate.
What are analogous characteristics?
Structures that look similar but have different evolutionary origins (have developed through convergent evolution)
What are homologous characteristics?
Structures that look different but have similar evolutionary origins (have developed through divergent evolution)
What is taxonomy the study of?
Classification
What is each group within taxonomy called?
Taxa
What are the three principles of taxonomy
There are smaller groups within a larger group, which are non-overlapping. These groups reflect their evolutionary history.
Describe why taxonomy is considered a hierachy
There are smaller groups within larger groups, which are non-overlapping.
Recall the 8 taxa, from largest to smallest
Domain, kingdom, phylum, class, order, family, genus, species
Name the three domains
Eukarya, Bacteria and Archaea
Name the kingdoms within the Eukarya domain
Animalia, Plantae, Fungi andProtoctista
Which two taxa comprises a binomial name?
Genus and species (Homo Sapiens)
How can you ascertain how closely related two species are from their classification?
The more taxa they have in common, the more closely related they are
Identify a circular taxonomy diagram
Why is phylogeny?
The evolutionary relationships between organisms
What is the diagram used in phylogeny called?
A phylogenetic tree
Where in a phylogenetic tree are oldest species, and where are the newest species?
Oldest species at the bottom, newest species at the top
Phylogenetic trees predict that time at which two species diverged from what?
Their common ancestor
How can the relatedness of two species be ascertained from a phylogenetic tree?
The more recent the divergence from their common ancestor, the more closely related two species are
