Unit 3, topic 1.1: Biodiversity Flashcards
Biodiversity
The variety of living species on earth, including plants, animals, bacteria and fungi
Types of biodiversity
Genetic, species and ecosystem diversity
Genetic diversity
The number of different alleles possessed by a species, determined through analytical DNA techniques such as DNA sequencing and DNA profiling
Species diversity
The number of different species present in an ecosystem: caused from evolution
Measures of species diversity
Species richness and species evenness
Species richness
Number of different species present in an ecosystem.
EQUATION:
S-1/logN
S= number of species present in the community
N= number of individuals in the community
Species evenness
Relative abundance of individuals of each species within an ecosystem.
Ecosystem diversity
Variations of ecosystems in a certain geographical location, in relation to the combined influences of biotic and abiotic factors
Biomes
A group of ecosystems which have a similar climate and other conditions which extend over a large area
Tolerance range
Set of environmental conditions within a species suitable survivable condition range
Measures of biodiversity
Percentage cover, percentage frequency, Simpson’s diversity index, Lincoln’s diversity index
Percentage cover
A measurement of the relative abundance of a species in a single area (the amount of the species covering a certain area)
Percentage cover can be calculated by estimating the percentage of each quadrat covered by any particular species: dividing quadrat into smaller units = more accurate
EQUATION:
%=(covered/total squares)*100
Percentage frequency
A measure of the appearance of plant species within sample quadrats
The percentage frequency is the number of quadrats containing the species of interest divided by the number of quadrats sampled, expressed as a percentage
EQUATION:
% freq. = (total number of quadrats in which the species occured/ total number of quadrats studies)*100
Simpson’s diversity index
Measure of diversity which takes into account the number of species present, as well as therelative abundanceof each species
EQUATION:
D = N(N-1)/∑n(n-1)
N= total number of organisms
n= number of organisms in each species
Lincoln’s index
Measures population sizes of individual animal species based of the capture, mark, recapture method
EQUATION:
N = M*n/m
M = number of individuals tagged and released in the first sampling
n = number of individuals caught in the second sampling
m = number of tagged individuals caught in second sampling
Species interactions
Species compete for resources, use each other as food and assist each other
→ can be positive, negative or neutral
Intraspecific species interaction
interactions occurring within organisms of the same species
Interspecific species interaction
interactions between individuals of different species
Predation (predator → prey relationship)
A biological interaction where one organism kills and consumes the other (predator and prey)
Competition
An interaction in which two organisms require a resource which is limited in supply (water, food, territory etc.)
Symbiosis
A close, prolonged interaction/relationship between two organisms
Types of symbiotic relationships
Commensalism, Mutualism, Parasitism, Neutralism, Competition & Predation
Commensalism
where one species benefits while the other is unaffected
Mutualism
both species benefit
Parasitism
One species benefits while one is harmed
Neutralism
both species unaffected
Abiotic factors influencing biodiversity
climate, substrate/soil, size/depth of area
Climate (AF influencing BD)
Number of factors including precipitation, temperature, wind direction, cloud cover and sunshine.
Affect the type and abundance of species present, e.g. desert climates with little rainfall means plant growth is slow and therefore herbivorous animals are scarce
Substrate/Soil (AF influencing BD)
Number of factors include thickness, structure/porosity, PH, nutrient content and salinity.
Factors influence type of soil present and therefore vegetation and formation of food chain: consumers, habitat growth
Size/depth of area (AF influencing BD)
Small areas reduce biodiversity due to competition for resources, genetic diversity lower due to smaller population sizes.
Aquatic area factors: light, depth, turbidity, oxygenation, temperature, water flow
