f212 biodiversity and evolution

Biodiversity 

a species is a group of individual organisms very similar in appearance, anatomy, physiology, biochemistry and genetics. whoose members are able to interbreed freely to produce fertile offspring.

a habitat is the place where an organism lives. 

biodiversity is the variety of life- the range of living organisms to be found.

Sampling Plants

random sampling means studying a small part of the habitat and assuming it contains a representative set of species that can be applied to the whole habitat. the sample sites must be chosen ay random.

how many sample should you take? in a field such as a football field you may need to record 10 samples.

a quadrat is a square frame ised to define the size of the sample area. usually either 50cm or 1m.

a transect is a line taken accrss the habitat. you stretch a long rope or tape measure accross the habitat and take sample along the line. you record the amount of plants at set intervals. you can also use a quadrat and drop it at set intervals along the line.

Sampling Animals

animals are harder to sample-animals move and any attempt to sample will disturb the habitat and animals detect your presence

left traps used so that animals do not know your coming

larger animals can be observed by hiding and waiting quietly

sweep nets- involves walking through a habitat with a stout net and sweep the net through the vegetation

pooters- this type of sample is suitable for low vegetation. you use this by sucking the insect through a tube and into a tub

tree beating- spread a white sheet and knock a brach with a stout stick

pitfall trap- this is a trap set in the soil to catch small animals. 

Sampling animals 

tullgren funnel- you place leaf litter in a funnel. a light above the litter drives the animals downwards as the litter dries out and warms up. they fall through the mesh screen to be collected in a jar underneath

light trap- you can use a light trap to collect flying insects as night. it consists of an ultraviolet light that attracts the insects. under the light is a collecting vessel containing alcohol

percentage cover gives quantitative data that can be compared and put into statistics

a line transect is just recording the plants that touch the line belt transect is placing a quadrat

Measuring Biodiversity 

simpsons diveristy indez

measures the diversity of the habitat

uses both richness and eveness          d=1-(n/N)

n=number of individuals of a particular species (or% cover in plants)

N=total number of individuals for all species (or% cover in plants)

the difference between species richness and species eveness is that species richness is the amount of species present in a habitat, and eveness is the measure of relative numbers or abundance of individuals in each species

a habitat with a high diversity tends to be more stable than one wth low diversity, due to the higher simpsons diversity index if a disease changes the enviroment, it could damage or destroy the whole habitat

Classification and taxomony

classification- process of placing living things into groups

natural- does this by grouping things according to how closely related they are and reflects evolutionary relationships

artificial- humans put them into groups

taxomomy- study of the principles behind classificatin 'differences between species'

phylogeny- study of evolutionary relationships between organisms

Classification

current system of classification (taxa)

• domain
• kingdom
• phylum
• class
• order
• family
• genus
• species

The 5 Kingdoms

prokaryotes

• have no nucleus
• have loop of naked dna
• have no membrane bound organelles
• carry out respiration not in mitocondria

protoctists

• are eukaryotes
• are mostly single celled 
• show various plant-like or animal-like features
• are mostly free living 

The 5 kingdoms Continued

fungi 

• are eukaryotes 
• have a mycellium
• have walls made of chitin
• are mostly free living and saprophytic-cause decay of organic matter 

plants

• are eukaryotes
• have cells surrounded by a cellulose cell wall
• produce multicellular embryos from fertilised eggs
• have autotrophic nutrition 

animals

• eukaryotes, multicellular, heterotrophic nutrition, able to move around

Naming Living Things

a dichotomous key uses a series of questions with two alternative answers to help you identify a speciman 

example

are the buds paired?   yes-go to question 2

                                     no-go to question 4

are the buds black?     yes-ash

                                      no-go to question 3

are the buds green?    yes-sycamore

                                      no-horse chestnut