Module 4 – Biodiversity By Ms Cullen

Terminology Try and define the following terms used when studying the environment.

Biosphere The outermost part of the planet’s shell – including air, land, surface rocks and water – within which life occurs.

Ecosystem Ecosystems are dynamic interactions between plants, animals, and microorganisms (biotic) and their physical environment (abiotic) working together as a functional unit. The abiotic environment includes climatic and edaphic (soil or water composition). Ecosystems will fail if they do not remain in balance. eg a coral reef

Species This is the fundamental unit of classification. A species is a group of similar individuals (in appearance, anatomy, physiology, biochemistry and genetics) that can interbreed and produce fertile offspring.

Habitat Is the place where a particular species lives and grows. It is essentially the environment – at least the physical environment – that surrounds (influences and is utilised by) a species population.

Biodiversity This is the variation of life forms within a given ecosystem, biome or the Earth. It includes all different plants, animals, fungi and microorganisms species. Biodiversity is often used as a measure of the health of biological systems.

It is estimated that there are 13 – 14 million different species on Earth. We have recorded about 2 million of these. Why have we only recorded such a small number? Where do you think the most species rich ecosystems are?

Possible Proportions of Total Species

Measuring the variety of nature & selecting priority areas for conservation GLOBAL BIODIVERSITY VALUE: a map showing the distribution of some of the most highly valued terrestrial biodiversity world-wide (mammals, reptiles, amphibians and seed plants), with red for high biodiversity and blue for low biodiversity.

What is sampling? Taking measurements of a limited number of individual organisms present in a particular area

Sampling – Random or Non-random? Random – means individuals are selected by chance. Non- random techniques include: -Opportunistic (not very representative) -Stratified (sub- groups eg male or female) -Systematic (usually a line or belt transect)

Reliability Sampling never gives a complete representation of organisms in a habitat because: Sampling bias Chance

Methods for Sampling Plants

Equipment used for Sampling Plants: Frame quadrats - usually 0.25m 2, 0.5m 2, 1m 2 Permanent quadrats. Point quadrats (pin frame). Line transect – only species touching transect recorded. Belt transect – area sampled between 2 line transects. Profile transect – includes height variations of species.

Randomising samples: Observe all species present and count how many individuals of each species there are within each sample. Take samples at regular distances across a habitat. Use random numbers generated by a computer or random number table to plot coordinates within the habitat. Select coordinates from a map of an area and use GPS to find exact position within habitat.

How many samples? This will depend on size of habitat and time available. If a habitat is uniform, valid results can be obtained by using 5 quadrats. If a habitat is not uniform then at least 10 quadrats need to sampled. The more species abundant a habitat appears the more quadrats should be done to give a clear picture.

Species Evenness (or Species Density) The number of individuals of a species within a given area.

Calculating Species Evenness A survey gave the following results for a species of plant – plantain, using a 0.25m 2 quadrat. Ten quadrats were placed so a total area of 10 x 0.25 = 2.5m 2 Total amount of plantain found in this area is 12. Therefore the species evenness is 12 = 4.8 per m 2 2.5m 2 Quadrat No of plantain

Species Richness The number of different species in a given area

Species richness and species evenness will affect biodiversity: Habitat x and y both contain 2 different species and 30 individual organisms. Species richness in the 2 different habitats is the same – 2. In habitat y the individual organisms are more evenly distributed between the 2 species therefore it has greater species evenness. Habitat xHabitat y Species Species 2215 Total30

The greater the species richness and species evenness in an area, the higher the biodiversity.

Species Cover A measure of the proportion of ground covered by the species. This is particularly useful when dealing with large numbers of small plants in a quadrat – too many to count.

Species Frequency A measure of the probability of finding a given plant species within a randomly placed quadrat in a given area. eg if a species only appears once in 10 quadrats it has a Species Frequency of 10%

Diversity is measured using Simpson’s Index of Diversity Simpson’s Index of Diversity (D) takes into account both species richness and evenness. It can be calculated using the following formula: D = 1 – [Σ(n/N) 2 ] n is the number of individuals of a species (or % cover of plants). N is the total number of all individuals of all species (or % cover for all plants). Σ is the sum Look at Tables 1 & 2 in OCR AS Biology book P

Using Simpson’s Index of Diversity A high value will indicate a diverse habitat. A low value reflects a habitat dominated by a few species, therefore it has a low biodiversity.

Carry out Practical Activity 31 Calculating Species Diversity and complete Qs

Activity 31 SpeciesNo. of individuals (n) n/N(n/N) 2 Total no. of individuals N = Sum Σ(n/N) 2= 1 – Σ =

Recording Species Use scientific names – binomial latin names. The first letter of the first name (Genus) should be a Capital letter, all other letters should be lower case eg Calluna vulgaris. You must check spelling carefully, incorrect spellings will loose marks!

Scientific Diagrams Clear, continuous lines for your sketch, use a SHARP pencil! NO SHADING! Diagram should cover at least 50% of space given. All label lines should be straight – use a ruler. Label lines should touch the structure you are identifying. Label lines should not have arrows on the end.

Sampling Animals Sweep nets Tree – beating Pitfall traps Pooters Tullgren funnel Light trap Capture and release Longworth trap for small mammals