Topic 4- Glossary Flashcards
Species
A group of actually or potentially interbreeding natural populations that produce fertile offspring and that is reproductively isolated from other such groups
Ecosystem
The community of living organisms and the biotic factors that affect them
Habitat
The place where the organisms live; the non-living part of an ecosystem
community
All the populations of living organisms living in a habitat at any one time
population
a group of individuals of the same species living in a particular habitat
adaptation
the features that help an animal or plant survive or reproduce. Adaptations can be classified as behavioural, physiological or anatomical
behavioural adaptations
Any actions by organisms which help them to survive or reproduce
physiological adaptations
Feature of the internal workings (biochemistry) of organisms which help them to survive or reproduce
structural adaptations
Features that can be observed or dissected, the possession of which helps an organism to survive or reproduce
biosphere
the part of the earth and its atmosphere which is inhabited by living organisms
abiotic
non -living factors - physical and chemical
biotic
living factors e.g. predation and competition
microhabitat
area of distinct conditions within a habitat e.g. underside of a stone in a pone
niche
the role an organism has in an ecosystem, including where it lives and what it eats, and the periods of time it is active. also known as ecological niche. No two species can occupy the same niche; one will out compete the other e.g. red and grey squirrels
endemism
refers to a group of organisms that are unique to a particulalr habitat, which must be geographically discrete, such as an island or a certain type of vegetation. WE say that a species restricted to one location is endemic.
biodiversity “hotspots”
Area in the world where the majority of species occur, contain at least 0.5% or more of total global plant diversity as an endemic species.
evolution
The gradual changes in behaviour or physiology of species over a long period of time
natural selection
Term given to the mechanism by which better adapted organisms live to produce more viable offspring and so pass on their genes. This has the effect of increasing their proportion in the population so that they become more common.
artificial selection
Selection of organisms by deliberate human intervention
gene pool
all the alleles of all the genes present in the population
biodiversity
The variability among living organisms from all sources; it includes diversity within species, between species and within and between ecosystems
binomial system
Naming organisms using a two-part latin name, the first being the Genus name and the second the species name
genus (Plural Genera)
A group of closely related species
dichotomous keys
Identification keys with two alternatives at each stage in the key
Hierarchical
A system of classifying organisms in nested groups, the members of each group sharing some common features
family
a group of genera sharing some characteristics
order
a group of families sharing some characteristics
class
a group of orders sharing some characteristics
taxa
classification groups in which all members share at least one common feature
homologies
common features
five kingdoms: animalia, plantae, fungi, protoctista, prokaryotae
The top 5 levels in the taxomonic heirarchy currently used to classify living organisms
prokaryotes
single celled organisms with DNA free in the cytoplasm and no membrane-bound organelles
eukaryotes
organisms made up of cells with membrane-bound organelles. The DNA is contained within a nucleus surrounded by a nuclear envelope
archaebacteria
Ancient lineage of bacteria distinct from other bacteria and from eukaryotes. Several biochemical characteristics, e.g .possession of novel 16S like ribosomal RNA component and a particular membrane composition, support this
3 domain system
The discovery of the above meant a rethink of classification to this system
phenotype
The appearance of an organism determined by interaction between its genotype and the envriionment
genotype
All the genes present in an organism
mutations
Changes in DNA that can occur spontaneously or as a result of external influences
independent/Random assortment
The random separation during meiosis of non-homologous chromonomes; so that each homologous pair of chromosomes can pass independently of another homologous pair of chromosomes, into a gamete
crossing over
the breaking and random rejoining of chromatids during the first prophase of meiosis. It results in the rearrangement of genetic material and is important source of genetic variation
chromatids
Two copies of the same chromosome, held together from the time of DNA replication, until the time at which the centromeres separate at the anaphase of nuclear division.
chiasmata
The visible manifestation of crossing over between homologous chromosomes. The point where the chromatids break and refujoin during the first prophase of meiosis
Species richness
This is the number of different types of species in a particular area. The greater the number of species, the ‘richer’ the area. This factor does not take into account the number of individuals of a particular species. so a species with just one individual carries the same weight as a species with a hundred individuals.
Species evenness
This is a comparison of the size of the population (i.e. the number of individuals) of different species within a particular area, i.e. indicates whether abundance is evenly spread across the species present.
Diversity index
A way of calculating species richness; Simpson’s diversity index is based on the probability that a second organism collected from a community will be of the same species as the first.
Biodiversity Hotspot
An area of high species richness such as the Mediterranean Basin which has one in ten of all the world’s species
Endemic
Found only in one particular area. A species is said to be endemic to an area if it is not found anywhere else on Earth.
Amyloplast
A colourless plastid, (double membrane bound organelle in plants) that stores starch
Chloroplast
Chlorophyll containing plastid, present in plants and most algae; the organelle in which photosynthesis takes place
Vacuole
membrane bound region which may take up to 90% of the plant cell volume. Contains cell sap (water, salts and sugars) - important for maintaining turgor pressure, and for storage of metabolites and waste materials.
Tonoplast
Vacuolar membrane
Parenchyma
Type of plant tissue found throughout the plant, fills spaces between specialised cells (“packing”) and may have certain specialised functions e.g. storage in roots, photosynthetic tissue in leaves.
Plant cell wall
Surrounds the plant cell surface membrane and provides rigidity to the plant cell. Composed of cellulose (cf bacterial cell walls), hemicellulose and pectins
Cellulose
Polymer of 1,4 linked B-glucose - a long unbranched molecule
B-glucose
Glucose isomer, where the OH on carbon 1 projects “up” in comparison to “down” on a- glucose
Microfibrils
Bundles of cellulose chains held together by H bonds between OH groups in neighbouring chains - produces a strong structure
Hemicelluloses and pectins
Hydrogen bonds bind the hemicelluloses (Long chain polysaccharides of 1,4 linked B-monomers) to the cellulose microfibrils. Pectin molecules (varied polysaccharide molecules) are negatively charged and bind Ca2+ and form a gel like matrix filling the spaces between cellulose microfibrils.
Middle Lamella
Region between cell walls of adjacent cells. Pectins act as a “molecular cement” holding the cells together.
Plasmodesma (sing) Plasmodesmata (plur)
Cytoplasmic tubes that pass through the cell walls of living plant cells, lined by the cell plasma membrane so that the cytoplasm and endoplasmic reticulum of one cell is continuous with the next.
Pit
Small areas where the cell wall between two plant cells is thin and the cell membranes are in close contact. Plasmodesmata often located here
Xylem vessels
Plant cells specialised for transport of water with heavily lignified cell walls. Loss of cytoplasm/organelles etc at maturity, and cell dies. End walls off adjacent cells are lost or perforated.
Sclerenchyma fibres
Elongated plant cells with tapering ends, specialised to supply mechanical support. Thick lignified cell walls and cell dies at maturity. Often present in groups.
Vascular bundle
Longitudinal strand of conducting tissue comprising essentially of xylem and phloem
Phloem
Transports products of photosynthesis, living cells, modified for transport - has a companion cell closely associated to provide products of metabolism and cells join end to end via sieve plates to form sieve tubes.
Ground tissue
Bulk of hte plant tissue, excepting the dermal and vascular tissue. Comprised of parenchyma, collenchyma and sclerenchyma cells.
Collenchyma Tissue
Cells which provide support for young growing plant structures e.g. stems. Cell walls with extensive cellulose but not lignified
Lignin
Complex polymer of phenylpropanoid units associated with cellulose. Makes plant cells strong, rigid and waterproof
Transpiration
Loss of water vapour from plant surfaces driven by heat from the sun and providing the motive force to raise water from the roots. Transpiration rates are influenced by levels of CO2, light, temperature, air movement, humidity and availability of soil water.
Water diffuses out through the stomata down a ———-, the steeper the gradient the faster diffusion occurs.
Diffusion gradient
Cohesion
attraction between water molecules. This helps to keep the water together as a continuous column
Adhesion
Attraction between water molecules and xylem vessel walls. This helps to hold the column of water within the vessel
Polar
An uneven distribution of charge. In water the hydrogens become slightly positive and the oxygen slightly negative because of the uneven distribution of electrons.
The positively charged end of the water molecule is attracted to the negative ends of surrounding molecules resulting in _________________
Hydrogen bonds
Water within the xylem vessels is under tension because the polar water molecules cling together in a continuous column pulled up the xylem by evaporation above. Because of cohesiveness of water, this tension is transmitted all the way down the stem to the roots. This is known as the ___________ ___________ theory.
Cohesion-tension theory
Mass flow system
The movement of water and ions within the xylem
magnesium
Inorganic ion required to make chlorophyll
Nitrates
Inorganic ion required for protein, nucleic acid, ATP and plant growth substance manufacture. A lack of this will result in poor growth and yellow leaves.
Calcium
Inorganic ion required for cell wall structure (forms a gel matrix with pectin) and permeability of the cell membrane. A lack of this will result in stunted growth.
Active transport
Transport of ions from the soil into the root hairs requires this method of transport across membrane
Turgid
When the plant has plenty of available water, the plant cell vacuole volume is high and the cell membrane pressed against the cell wall. This aids mechanical support of plant tissues.
Retting
Process of softening plant tissues in order to extract fibres. This may require the action of bacterial or fungal enzymes, or chemical treatments (e.g. caustic alkali)
Pyrethrum
Plant which produces the chemical Pyrethrin, an insecticide
Allicin
Active antibacterial ingredient in garlic
Alliin
Inactive antibacterial precursor in garlic
Alliinase
The enzyme which converts the inactive precursor into the active antibacterial agent in garlic
Digitalis
The plant which contains digitalin, used to treat oedema and irregular heart rhythm
Oedema
Swelling of tissue due to an increase in the volume of tissue fluid in that tissue
Pre-clinical testing
Laboratory and animal studies to assess efficacy and safety of potential drug
Phase I clinical trials
Testing of healthy volunteers. allows an analysis of absorption, distribution, metabolism, and excretion of a drug as well as any side effects.
Phase II clinical trials
Testing of a small group of volunteers with the disease to test drugs effectiveness
Phase III clinical trials
Testing of a large group of patients, using the drug, a placebo and using double blind tests
Placebo
An inactive compound administered to half the patients during phase II clinical trials to rule out psychological effects
Double blind test
where neither the patient nor the doctor know if the patient is receiving the drug or the placebo
Radicle
young root
Plumule
young shoot
Cotyledons
Seed leaves - mono = 1, di= 2
Endosperm
Storage tissue in the seed
Testa
Seed coat
Fruit
Ovary will develop into this
Dormancy
Where seeds do not germinate immediately, even in favourable conditions, until this is broken
Micropyle
Small pore in the seed coat through which water can enter
Gelatinisation
The process of starch absorbing water when heated
Sizing
The process of stiffening of cloth or paper by starch gelatinistion followed by cooling, so that bonds form between the starch molecules.
Plasticisation
Reversing the stiffening process by adding water.
Starch foam
Formed using high temperatures and pressure and
Biodiesel
Use of vegetable oils as a fuel in e.g. car engines
Sustainability
Long term production of resources without damage to the environment
Renewable
A resource that can be replaced and its production is sustainable
Carbon dioxide neutral
e.g. wood - the release of CO2 upon combustion is counterbalanced by the amount of CO2 that was absorbed by photosynthesis. Thus there is no net increase in CO2 into the atmosphere.
Ex situ convseration
Conservation activities taking place outside the organism natural habitat - “off-site”
In situ conservation
Conservation activities taking place within the organism natural habitat - “in-site”
Captive breeding programme
A programme to breed animals in captivity with a view to reintroducing them to the wild and maintaining hererozygosity
Genetic Drift
The random changes in allele frequency that occur in all populations, but are much more pronounced in small populations. These differences result from random mutations adding new alleles to the population, or from loss of alleles in a population due to organisms carrying particular alleles failing to breed. In a small population this can have a great effect on allele frequencies.
Inbreeding
Small populations have limited pools and mating individuals with similar genotypes can reduce the gene pool still further
Inbreeding depression
If related individuals breed the frequency of homozygous recessive genotypes increases. Many of these recessive alleles have harmful effects.
Founder effect
Occasionally, a small number of individuals from a large population may migrate away, or become isolated from their original population. If this new population is made up of only a few individuals, it will probably have non-representative alleles from the parent population’s gene pool. The colonizing population may evolve differently from that of the parent population, especially if the environmental conditions are also different.
stud books
A record of all the captive animals of a species in the places that are co-operating in an overall breeding plan
Flagship species
Conservation of popular species to increase public awareness of the many potential threats of extinction
Reintroduction
Returning captive bred animals to their natural habitat. They need training to behave appropriately
Seedbanks
Conservation of plant species by storage of seeds in these facilities. Viability is ensured by storing in cold and dry conditions.
