2883424
Description
Flashcards by Taran Sahota, updated more than 1 year ago
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Created by Taran Sahota
almost 9 years ago
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| Question | Answer |
| Community | All the populations of different species interacting together in a habitat at a given time |
| Habitat | The conditions in which an organism lives, which is composed of both biotic and abiotic factors |
| Environment | A well defined area in which an organism lives e.g. hedgerow or pond, oakwood or rocky shore |
| Population | The members of one species living in one habitat at a given time |
| Niche | Where an organism lives in a habitat and its role in the habitat |
| Ecosystem | Self contained ecological unit of community of living organisms in conjunction with the non-living components of their environment (community + environment) |
| Random Sampling | Used to avoid bias in collecting data to ensure that the data obtained is valid |
| Abundance | Counting the number of individuals of a species in a given space |
| Systematic sampling | Samples are taken at regular intervals within a set sample area |
| Percentage cover | An estimate of the area within a quadrat that a particular plant species covers |
| Mark-release-recapture | Known number of animals caught, marked and released. Some time later given number of individuals are collected and randomly and mark recorded. |
| Frequecy | Th likelihood of a particular species occuring in a quadrat |
| Mark-recapture-release method relies on what assumptions? | 1 - Marked individuals distribute themselves evenly 2 - Population has a definitive boundary 3 - Mark is not toxic 4 - Mark is not lost 5 - Few births or deaths |
| Mark-recapture-release equation | no of organisms in sample 1 X no of organisms in sample 2 -------------------------------------------- no of marked organisms recaptured |
| Factors that affect population size | Abiotic and biotic factors |
| Definition of abiotic factors | Non-living part of the environment |
| Examples of abiotic factors | Light, temp, wind, water availability, humidity, salinity (salt), water movement, O2 concentration, soil, pH |
| Definition of biotic factors | The effect of living organisms and how they interact (tend to have greater impact in later stages of succession) |
| Examples of biotic factors | Symbiosis, mutualism, parasitism, disease |
| Symbiosis | Intimate relationship between members of 2 species, the survival of a species relies on the success of another species e.g. bee pollinating plants |
| Mutualism | A type of symbiosis between a pair of species that is mutually beneficial e.g. Lichen - algae + fungus |
| Parasitism | A type of symbiosis where the host gives and the parasite takes e.g. ivy growing on a tree |
| Disease | Caused by pathogens |
| Interspecific Competition | Competition between organisms of different species |
| Intraspecific Competition | Competitions between organisms of the same species |
| Phosphorylation | The process of adding a phosphate group (ADP+ Pi = ATP) |
| Light Dependent Reaction | Stage of photosynthesis in which light energy is required to produce ATP and reduced NADP |
| Oxidation | Loss of electrons, combining oxygen with a substance |
| Reduction | Gain of electrons, loss of oxygen from a substance |
| Electron Carrier Molecules | A chain of carrier molecules along which electron pass releasing energy in the form of ATP |
| Photolysis of Water | Light energy splits water molecule, yielding electron, hydrogen ions and oxygen (light-dependent reaction) |
| Calvin Cycle | A biochemical pathway (part of the light-independent reaction) where CO2 is reduced to form carbohydrate CO2 + RuBP = GP =TP = Glucose or RuBP |
| Limiting Factor | A variable that limits the rate of a chemical reaction |
| Glycolysis | First part of cellular respiration in which glucose is broken down (in the cytoplasm) to 2 molecules of Pyruvate |
| Link Reaction | Process linking glycolysis to the Krebs cycle (in the matrix of the mitochondria), where the 2 molecules of pyruvate are converted into CO2 and Acetylcoenzyme A |
| Krebs Cycle | Introducing acetylcoenzyme A into a cycle of oxidation-reduction reactions (in the matrix of the mitochondria ) that yield some ATP and large number of electrons |
| Electron Chain Transport | Use of electron from Krebs cycle to synthesis ATP via a series of oxidation-reduction reactions |
| Anaerobic Respiration | Releasing energy from glucose without oxygen (produces lactate = lactic acid) |
| Trophic Levels | Each stage in a food chain |
| Consumer | An organism that obtains its energy by feeding on other organisms |
| Gross production | Total quantity of energy that plants in a community convert into organic matter |
| Net Production | Gross production - respiratory losses |
| Energy Transfer | (Energy available after the transfer/energy available before the transfer) x 100 |
| Pyramid of Number | A pyramid drawn with bar lengths proportional to the number of organisms present |
| Pyramid of Biomass | A pyramid drawn with bars proportional to the mass of the plants/animals |
| Pyramid of Energy | A pyramid drawn with bars proportional to the energy stored in organisms |
| Biological Control | Controling pests by introducing pedators |
| Chemical Control | Controlling pests by using various chemicals |
| Integrated Pest Control System | Controlling pests by using both biological and chemical controls |
| Selective Breeding | Breeding of organism by human selection of parents for certain characteristics |
| Saprobiotic Micro-organisms | An organisms that gets its food from the dead or decaying remains of other organisms |
| Greenhouse Gases | Gases such as methane and CO2 which trap more heat energy raising the Earth temp |
| Ammonification | Production of ammonia from urea and proteins |
| Nitrification | Converting ammonia into nitrites then nitrates |
| Nitrogen fixation | Conversion of nitrogen gas into nitrogen-containing compounds |
| Denitrification | Conversion of soil nitrates into nitrogen gas |
| Leaching | Process by which nutrients are washed from the soil into watercourses |
| Eutrophication | Consequences of an increase in nutrients in watercourses that leads to a decrease in biodiversity |
| Succession | The changes in an ecosystem, over time, of the species that occupy it |
| Pioneer Species | A species that can colonise bare rock of ground. They are the first plant that colonise the bare ground |
| Climax Community | The stable, final community that exists in balanced equilibrium |
| Conservation | Management of the Earth's natural resources in such a way that maximum use can be made of them in the future |
| Genotype | The genetic composition of an organism |
| Phenotype | The (visible) characteristic of an organism, often resulting from its genotype and the environment |
| Gene | A length of DNA that codes for a polypeptide |
| Allele | One form of a gene |
| Homologous Chromosomes | A pair of chromosomes that have the same gene loci and determine the same features |
| Dominant | An allele that is always expressed in the phenotype |
| Recessive | An allele that is only expressed in the phenotype if there is another identical allele |
| Heterozygous | When the alleles are different for a particular gene |
| Homozygous | When the alleles are the same for a particular gene |
| Sex Linkage | Any gene that is carried on the X or Y chromosome (Women = XX Men = XY) |
| Co-dominance | Both alleles are equally dominant and are both expressed in the phenotype |
| Multiple Alleles | More than 2 possible alleles for a particular gene |
| Gene Pool | Al the alleles of all the genes of all the individuals of a population at a given time |
| Allelic Frequency | The number of times that allele occurs within a gene pool |
| Stabilising Selection | Selection that favours average individuals |
| Directional Selection | Selection that favours individuals at one extreme |
| Speciation | The evolution of new species from existing species |
| Geographical Isolation | When a physical barrier prevent 2 populations from breeding with one another |
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