biodiversity Flashcards
species
group of organisms that can breed to produce fertile offspring
population
group of organisms of same species, living in same area at the same time
community
group of populations living and interacting with each other in an area
ecosystem
community and its abiotic environment
Binomial naming system
First name is generic name- denotes genus which organism belongs to
second name- denotes species
Names are printed in italics or if hand written underlined to indicate that they are scientific names
First letter of genus is upper case but rest of genus and all of species name is lower case
is specific name is not known can be written as sp
courtship behaviour
Courtship behaviour helps achieve mating by enabling individuals to:
1- recognise members of their own species
2- identify a mate that is capable of breeding. Both mates must be sexually mature, fertile and receptive to mating
3- form a pair bond. Lead to successful mating and raising of offspring
4- synchronise mating- takes place when maximum possibility of sperm and egg meeting
5-became able to breed by bringing member of opposite sex into correct physical state that allows breeding to occur
principles of classification
Artificial classification- divide organisms according to differences that are useful at the time eg colour, size, leaf shape etc. Described as analogous characteristics as have same function but don’t have same evolutionary origins eg wings are used for flight but originated in different ways
Phylogenetic classification- based on evolutionary relationships between organisms and their ancestors. Classifies species into groups using shared features derived from their ancestors. Arranges groups into a hierarchy in which groups are contained within larger composite groups with no overlap. Partly based on homologous characterstics. These have simmilar evolutionary origins regardless of their functions eg wing of bird, arm of human and front leg of horse
classification
grouping of organisms
taxonomy
theory and practice of biological classification
types of domains
Each group within a phylogenetic classification is called a taxon.
Domain is highest taxonomic rank. Split into
1-bacteria- have no membrane bound organelles, unicellular, 70S ribosomes (smaller), murein cell walls, single loop of DNA but no histones
2- archaea- group of single celled prokaryoes that were originally classified as bacteria. They differ from bacteria because: genes and protein synthesis more similar to eukaryotes, membranes contain fatty acid chains attached to glycerol by ETHER linkages, no murein in cell walls, have more complex form of RNA polymerase
3- eukarya
eukarya domain
Divided into 4 kindoms
protoctista
fungi
plantae
animalia
Within each kingdom largest groups are known as phyla. Organisms in each phylum have a body plan radically different from organisms in any other phylum.
Diversity within each phylum allows it to be divided into classes, then orders then families, then genera and then species
Phylogeny
Hierarchical order of taxonomic ranks based on supposed evolutionary line of descent of group members. This evolutionary relationship between organisms is known as phylogeny. Phylogeny of an organisms reflects evolutionary branch that leads up to it. Usually represented by phlogenetic tree. OLDEST species at base of tree, while more recent ones are at ends of branches
Biodiversity
variety of organisms living in an area
species diversity
number of different species and the number of individuals of each species within any one community. One way to measure may be species richness (number of different species in a particular area at a given time)
ecosystem diversity
range of different habitats from small local habitat to whole earth
genetic diversity
variety of genes possessed by the individuals that make up a population of a species
index of diversity
d=N(N-1)
———-
£n(n-1)
d= index of diversity
N= total number of organisms of all species
n= total number of organisms of each species
£= sum of
Is a quantitative value so makes it easy to compare diversity in variety of different habitats so is more precise and easier than qualitative descriptions
impact of agriculture
- farmers often select species for particular qualities. As a result the number of species and genetic variety is reduced to the few that exhibit these desired features.
If one particular area is taken up with species that is considered desirable by farmer there is less room/ small area available for other species. These other species will have to compete for what little space and rescources are left
Pesticides are used to exclude these species as compete for light, mineral ions and water by with the farmed species. Farming therfore reduces species diversity
practices that have directly removed habitats, for food
- removal of hedgerows
- creating monocultures
- filling in ponds and draining marsh and other wetland
- over grazing of land
- pesticides and fertilisers
-lack of intercropping - escape of effluent from silage stores and slurry tanks into water courses
conservation techniques
- maintaining existing hedgerows at most beneficial height and shape. A shape provides best shape
- plant hedges as field boundries
-maintaining existing bonds and creating new ones - leave wet corners of fields rather than draining them
- plant native trees on land with low species diversity rather than in species rich areas
-reduce the use of pesticides- biological control where possible or genetically modified organisms that are resistant to pests - use organic fertilisers
- use crop rotation- nitrogen fixing crop
- intercropping
- create natural meadows
- introduce conservation headlands
- leave cutting of verges and field edges until after flowering when seeds have dispersed
comparison of observable characteristic
Traditionally, genetic diversity was measure by observing the charactersistics of organisms. Method is based on fact that each observable characteristic is determined by a gene or genes. The varierty within a characteristic depends on the number and variety of alleles of that gene
limitations- large number of them are coded for by more than 1 gene, polygenic, not discrete, difficult to distinguish, characteristics may be modified by environment
comparison of DNA base sequences
- advancment of gene technology means various techniques can now determin the exact order of nucleotides on DNA
Each nucleotide base can be tagged with different fluorescent dye- produces a series of coloured bands A- green T- red C- blue and G- yellow
We can measure genetic diversity of a species by sampling the DNA of its members and sequencing it to produce a pattern of coloured bands
Analysis of these patterns allows us to compare one species with another or one individual with another of the same species to determine how diverse they are
Patterns are scanned by lasers as process would be slow with human eye
Can also use these techniques to determine evolutionary relationships between species. Species more closley rleated will show more similarity in DNA sequences than those more distantly related due to mutations.
Can also compare base sequence of mRNA as it is complementary to that on DNA
COMPARISON OF AMINO ACID SEQUENCE IN PROTIENS
degree of similarity in the amino acid sequence of the same protein in 2 species will reflect how closley related the two species are.
Can be compared by counting number of similarities or differences in a sequence
Random sampling
If individuals sampled are representative of population as a whole measurements can be relied upon.
Sampling bias- selection process may be biased, may be unrepresentative choices being made either deliberately or unwittingly.
chance- even if sampling bias is avoided, individuals chosen may be pure chance not representative
Best way to avoid this is to use random sampling
1- divide area of study into grid of numbered lines
2- use random numbers to obtain a set of coordinates
3- take samples at intersection of each pair of coordinates
how to minimise effect of chance
- use large sample size- reduce probability that chance has caused the result
analysis of data collected- use statistical tests to determine the extent to which chance has influenced the data. These tests allow us to decide whether any variation observed is as a result of chance or some other cause
normal distribution curve
things that affect curve
- mean. Gives average value and is useful for comparing samples. Doesnt provide any info about range of samples.
-mode
-median
Skewed distribution means that mean, mode and median have different values
standard deviation
use standard deviation to measure the width of the curve. Gives indication of range of values either side of the curve.
Distance from mean to point of inflection, where curve changes from being convex to concave
square root of
£(x-x-2)
————-
n-1
£= sum of
x= measured value
x- = mean value
n= total number of values in the sample
