MODULE 6 Flashcards
transcription factors
proteins that bind to DNA and switch genes on and off by increasing or decreasing the rate of transcription
body plan
is the general structure of an organism arranged in a particular way
apoptosis
when some cells die and break down as a normal part of development
continuous variation
where the individuals in a population vary within the range and there are no distinct categories
discontinuous variation
when there are two or more distinct categories so no intermediates
gene
a sequence of bases on a DNA molecule that codes for a protein which results in a characteristic
allele
a different version of a gene
genotype
the alleles an organism has
phenotype
the characteristics the alleles produce
dominant
an allele whose characteristic appears in the phenotype even when there is only one copy
recessive
an allele whose characteristic only appears in the phenotype if 2 copies are present
codominant
alleles that are expressed in the phenotype, neither one is recessive
locus
the fixed position of a gene on a chromosome
homozygote
an organism that carries 2 copies of the same allele
heterozygote
an organism that carries 2 different alleles
carrier
a person carrying an allele which is not expressed in the phenotype but that can be passed on to the offspring
epistasis
when the allele of one gene masks the expression of the alleles of other genes
evolution
the change in allele frequency
allele frequency
how often an allele occurs in a population
stabilising selection
individuals with alleles for characteristics towards the middle of the range are more likely to survive and reproduce
directional selection
individuals with alleles for characteristics of an extreme type are more likely to survive and reproduce
genetic drift
chance dictates which alleles are passed on
genetic bottleneck
an event that causes a big reduction in a populations size, leading to a reduction in the gene pool
artificial selection
when humans select individuals in a population to breed together to get desirable results
speciation
development of new species
species
a group of similar organism that can reproduce to give fertile offspring
geographical isolation
when a physical barrier divides a population of a species
genome
all the genetic material in an organism
genetic engineering
manipulation of an organisms DNA
recombinant DNA
DNA formed by joining together DNA from different sources
transgenic organism
an organism that has been genetically engineered to include a gene from a different species
somatic therapy
involves altering body cells, particularly cells that are most affected by the disorder
germ line therapy
involves altering the alleles in the sex cells
vegetative progpagation
the production of plant clones from non reproductive tissues
biotechnology
the industrial use of living organisms to produce food, drugs and other products
batch fermentation
where microorganisms are grown in individual batches in a fermentation vessel. when one culture ends, its removed and then a different batch of microorganisms is grown in the vessel. closed culture
continuous fermentation
where microorganisms are continually grown in a fermentation vessel without stopping. nutrients are put in and waste products out at a constant rate.
closed culture
when growth takes place in a vessel that is isolated from the external environment
habitat
the place where an organism lives
population
all the organisms of one species in a habitat
producer
an organism that produces organic molecules using sunlight energy
consumer
an organism that eats other organism
decomposer
an organism that breaks down dead or undigested organic material
trophic level
a stage in a food chain occupied by a particular group of organisms
ecosystem
all organisms living in a certain area and all the non living conditions
biotic factors
the living features of an ecosystem (predators/food)
abiotic factors
non living features of an ecosystem (temp/ph of water/ soil nutrient availability)
gross productivity
available energy that is taken in
respiratory loss
energy lost to the environment when organisms use energy produced from respiration for movement or body heat
net productivity
is the amount of energy that is available to the next trophic level
succession
process by which an ecosystem changes over time
primary succession
happens on land that has been newly formed or exposed as there is no soil or organic material to start with.
secondary succession
happens on land that has been cleared of all plants, but where soil remains
abundance
the number of individuals of one species in a particular area
distribution
where a particular species is within the area you are investigation
frame quadrat
is a square frame divided into a grid of 100 smaller squares by strings attached across the frame
point quadrat
is a horizontal bar on 2 legs with a series of holes at set intervals along its length
line transects
a tape measure is paced along the transect and the species that touch the tape measure are recorded
belt transects
data is collected along the transect using frame quadrats placed next to each other
population size
total number of organisms of one species in a habitat
interspecifc competition
when organisms of different species compete with each other for the same resources
intraspecific competition
when organisms of the same species compete with each other for the same resources
conservation
the protection and management of ecosystems so that the natural resources in them can be used without them running out
reclamation
restoring ecosystems that have been damaged or destroyed so they can be used again
preservation
protection of ecosystems so they are kept exactly as they are
