Biodiversity and populations
The variety of alleles within a population or species.
genetic diversity
An organism’s role, resource use and interactions within its ecosystem.
ecological niche
Alternative forms of the same gene.
alleles
A small circular DNA molecule commonly found in bacteria and used as a vector in genetic engineering.
plasmid
A change in allele frequencies within a population over generations.
microevolution
The number of different species present in an ecosystem.
species richness
An interaction in which both species benefit.
mutualism
The process that produces four genetically different haploid cells from one diploid cell.
meiosis
This enzyme cuts DNA at specific recognition sequences.
restriction enzyme
The movement of alleles between populations when individuals migrate and reproduce.
gene flow
This sampling device is used to estimate the abundance or percentage cover of organisms within a defined area.
quadrat
The energy remaining after producers have used some of their captured energy in respiration.
net primary productivity
This event during meiosis exchanges DNA between homologous chromosomes, producing new allele combinations.What is crossing over?
crossing over
This enzyme joins DNA fragments by forming bonds in the sugar–phosphate backbone.
DNA ligase
A chance event greatly reduces a population’s size and changes its allele frequencies.
bottleneck effect
This population growth pattern slows as the population approaches carrying capacity, producing an S-shaped curve.
logistic growth
Succession beginning in an area where soil remains after a disturbance such as fire or farming.
secondary succession
A mutation caused by the addition or removal of nucleotides that changes how the remaining codons are read.
frameshift mutation
The biotechnology process used to produce millions of copies of a selected DNA region.
polymerase chain reaction (PCR)
Sharks and dolphins independently evolved similar streamlined body shapes because they experienced similar selection pressures.
convergent evolution
Scientists capture 80 animals, mark and release them, then capture 100 animals and find 20 marked. Using the Lincoln index, this is the estimated population size.
400 animals
These early colonisers modify harsh environments and make conditions more suitable for later species.
pioneer species
Two heterozygous parents are crossed: Aa × Aa. This is the probability that their offspring will have the recessive phenotype.
25% or one-quarter
During gel electrophoresis, these DNA fragments move further through the gel than larger fragments.
are smaller DNA fragments?
A population becomes separated by a mountain range, restricting gene flow until the groups become reproductively isolated.
allopatric speciation?