On the Wild Side Flashcards
Describe abiotic factors.
Physical or chemical factors: Solar energy input Climate Topography (altitude, slope, aspect, drainage) Oxygen concentration Edaphic (soil pH and mineral content) Pollution Catastrophes.
Describe biotic factors.
Living factors: Competition Grazing Predation Disease Parasitism Mutualism.
These factors are density dependent.
Describe anthropogenic factors.
Human activity.
Describe primary succession.
Colonisation is led by a pioneer species.
The environment becomes altered when the pioneer species die and change the abiotic environment through releasing nutrients into the soil.
The final species is the climax community.
Secondary succession.
Occurs in areas where a disturbance has removed most or all of the species living in the previous ecological community but has left behind rich soil.
Some species may remain and recolonise after the disturbance
Define gross primary productivity.
The rate at which energy is incorporated into organic molecules.
Define autotrophs.
Organisms that can make their own organic compounds from inorganic compounds.
Define net primary productivity.
The rate at which energy is transferred into the organic molecules making up cell biomass.
What is the calculation for net primary productivity?
Net primary productivity = gross primary productivity minus respiration.
Describe light-dependent photosynthesis.
Occurs in the thylakoid membrane.
Light energy excites electrons in the chlorophyll
Electron from PSll travels down the electron transport chain via a series of redox reactions.
Energy is used to synthesis ATP in photophosphorylation.
Electrons from PSII replace those from PSI.
Photolysis occurs, producing oxygen gas, H+ ions and electrons.
The electrons from PSl and the hydrogen ions combine with NADP to form reduced NADP.
Describe light-independent photosynthesis.
1) Carbon dioxide diffuses into the stroma of the chloroplast.
2) The CO2 combines with a 5-carbon compound: Ribulose bisphosphate (RuBP). This reaction is catalysed by the enzyme ribulose bisphosphate carboxylase (RuBISCO).
3) The 6- carbon compound formed is unstable and immediately breaks down into 2 3-carbon molecules : glycerate 3-phosphate (GP).
4) This 3-carbon compound is reduced to form a 3-carbon sugar phosphate: glyceraldehyde-3-phosphate (GALP). The hydrogen for the reduction comes from the reduced NADP from the light-dependent reactions. ATP from the light-dependent reactions provides the energy required for this endothermic reaction.
5) ⅚ of the GALP is involved in the recreation of RuBP. The molecules rearrange to form 5- carbon compounds which are then phosphorylated using ATP to form RuBP.
6) ⅙ of the GALP is involved in the formation of glucose which can then be used to make other materials that the plant needs like scratch, sucrose and cellulose.
Describe primary consumers.
Herbivores. Heterotrophs that eat plant material.
Describe secondary consumers.
Carnivores. Eat primary consumers.
Describe tertiary consumers.
Eat other consumers.
Describe detritivores.
Primary consumers that feed on dead organic materials (detritus).
Describe peat bogs.
Anaerobic and acidic.
Plants all have different types of pollen. Pollen grains have a tough outer layer that is decay resistant. Peat forms in layers. Each plant has specific conditions.
Describe dendrochronology.
Trees grow new layers of xylem vessels. New vessels grow in accordance to season. Wide vessels in spring, narrow vessels in summer.
Describe DNA hybridisation.
When DNA is heated, base pairs break. We can mix it to make a hybrid. Not all bases complementary base pairs. Hybrid DNA denatures at lower temperatures.
Define profile sequencing.
Compares sequence of bases in different species. Fewer differences are more common ancestors.
