Definitions Flashcards
Abiotic Factors
Abiotic factors are non living variables that can influence where organisms can live. E.g. light intensity, temperature, soil pH, soil moisture.
Biotic Factors
Biotic factors are interactions associated with living organisms. They can also influence the distribution of organisms in an ecosystem. E.g. competition for environmental recourses, grazing, predation, disease, food availability.
Adaptation
The evolutionary process whereby an organism becomes better able to live in its habitat or habitats.
Biodiversity
Where all different kinds of life are in one area.
Biological oxygen demand
The amount of polluting material in a body of water can be determined by the biological oxygen demand.
Biotic index
Biotic index is a scale for showing the quality of an environment by indicating the types and abundances of organisms present in a representative sample of the environment.
Capture-mark-recapture
A technique used to estimate an animals population size.
Density
Species density refers to the number of individuals of a species in an area.
Dissolved oxygen concentration
The level of free, non-compound oxygen present in water or other liquids.
Distribution
The general structure of the species population.
Diversity Index
A quantitive measure that reflects how many different types of species there are in a community.
Ecosystem
A community of interacting organisms.
Ecosystem Diversity
Refers to the number of distinct ecosystems present in a defined area.
Frequency
How common an allele is in a population.
Genetic diversity
Relates to genetic variation of the number and frequency of alleles of a specific gene.
Interquartile range
Spread of the middle 50% of the data values.
Lincoln Index
Total population = No. of animals in 1st sample + total No. of second sample divided by number of marked species in the second samples.
Percentage cover
To estimate the percentage cover of a species in a quadrat, count the number of squares that are more than half covered with the species.
Quadrat
A frame used to isolate a standard unit of area.
Qualitative data
Information about properties that are observed and generally cannot be measured numerically.
Quantitative data
The use of math,statistical or computational techniques to measure living organisms.
Random sampling
Used to select a sample that is unbiased.
Relative abundance
Compares the similarity of the population size of each of the species present.
Reliability
How many times you repeat an experiment.
Simple random sampling
Organisms sampled randomly e.g. randomly thrown quadrat.
Simpson biodiversity Index
A measure of the relationship between the number of different species in a habitat and the number of individuals within each species.
Species
A living organism that can interbreed and produce fertile offspring.
Species diversity
The 2 main factors taken into account when measuring species diversity are richness and abundance.
Species richness
The more species present in a sample, the richer the sample.
Standard deviation
A measure of data spread.
Stratified random sampling
To devide a habitat into zones which appear different and take samples from each zone.
Systematic random sampling
Selects a random starting point from the population, then a sample is taken from regular fixed intervals of the population depending on its size.
Transect
A line across a habitat place where plants, animals and micro organisms live.
Trent biotic index
The Trent biotic index is an index used to measure the quality of freshwater, based on the diversity and abundance of invertebrates present in a stream or river.
Validity
Scientifically accurate information.
