biodiversity Flashcards
define biodiversity
number of species and the number of individuals of each of the species within any one community.
define species richness
no. of different species in community.
define community
All the individuals of all the species living together in the same area at the same time.
define species
- Group of similar organisms / organisms with similar features / organisms with same genes;
- Reproduce to produce fertile offspring;
define genetic diversity
difference in DNA/base sequence/alleles
define ‘niche’
An organism’s role / in the ecosystem / community;
It describes what the species is like, where it occurs, how it behaves, how it interacts with other species and how it responds to the environment.
No 2 species occupy the same niche due to interspecific competition.
define ‘habitat’
place organism normally lives in ecosystem (characterized by biotic & abiotic factors)
what is diversity index?
diversity index = N(N-1)
——————-
sum of n(n-1)
N = total no. organisms of all species
n = total no. organism in each species
What information is required to calculate an index of diversity for a particular community?
Number of species;
Number of individual in each species;
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;
Give 2 advantages of using an Index of biodiversity rather than an indicator species
You do not need to identify each species;
Index takes into account the number of organisms of each of the species.
some species may be present in high/low numbers
what does high diversity show about an ecosystem?
- high stability
- has suitable climate, nutrients, shelter, space to support large range of species
- less likely disease or climate change affect every organism so ecosystem can continue
Suggest one economic argument for maintaining biodiversity.
- medical / pharmaceutical uses;
- commercial products / example given;
- tourism;
- agriculture;
- saving local forest communities;
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;
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);
what do binomial names tell us about a species?
1st word - genus name
2nd word - species name
what is the highest taxonomic rank of organisms and what are the 3 groupings?
domain
1. bacteria - single celled prokaryotes that have:
- no membrane bound organelles
- small 70s ribosomes
- murein cell wall
- circular DNA, not associated w histones
- archea - single celled prokayotes that have:
- genes & protein synthesis more similar to eukaryotes
- FAs & glycerol joined by ether bonds not ester bonds
- no murein in cell walls
- more complex RNA polymerase - eukarya domain divided into 4 kingdoms:
- protctisa, fungi, plantae, animalia
what are the 8 different taxonomic groups?
domain
kingdom
phylum
class
order
family
genus
species
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explain whta is meant by a heirarchy
- Groups within groups;
- No overlap (between groups);
explain what is meant by phylogenetic group
(Grouped according to) common ancestry;
what is a phylogenetic tree
- shows evolutionary relationships
- organisms that shared the same common ancestor more recently have branches closer together
- where the branches converge shows where they share a common ancestor
what is courtship behaviour?
- so organisms can attract a mate of right species and sex and ensure reproductive success
- genetically determined so organisms that are more closely related display similar patterns of courtship behaviour
Give two ways in which courtship 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 do modern classification method use:
- frequency of measurable or observable characteristics
- base sequence of DNA
- base sequence mRNA
- AA sequence of proteins encoded by DNA & mRNA
why can’t we observe the reproductive behaviour of some organisms or see if their offspring are fertile?
- they’re extinct
- they reproduce asexually
- practical/ethical issues
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;
Give two ways doctors could use base sequences to compare different types of HPV.
- Compare DNA base sequence
- Compare mRNA base sequence
- Look for Mutations
Describe how comparisons of biological molecules in two species could be used to find out if they are closely related. (6)
(N.B. if they are different species they are looking for a common ancestor- Phylogeny )
(Compare) DNA;
Sequence of bases/nucleotides;
Compare Cytochrome C (mitochondria) same/named protein;
Sequence of amino acids /primary structure;
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;
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
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);
