A3 Unity and Diversity : Organisms Flashcards
Diversity and classification
species
A group of similar organisms capable of breeding and producing fertile offspring.
binomial nomenclature
Naming system for living organisms using two names for each species; the genus followed by the species.
sexual dimorphism
When the male and female of a species look significantly different. Often having completely different features and appearance.
interbreeding
Breeding between species. Produces infertile hybrid offspring.
autosomes
Chromosomes that do not play a role in determining the biological sex of an organism.
diploid cell
Cells that contain two copies of each autosome and two sex chromosomes. Diploid cells have an even number of chromosomes.
speciation
The formation of new species by the splitting of one pre-existing species into two or more new species.
karyotyping
Determining or analysing the karyotype (number, size and shape of the chromosomes) of an individual.
karyogram
The image created by sorting, matching and aligning the chromosomes of an individual allowing for the visual interpretation of the chromosome characteristics.
centromere
Central region of a chromosome pair where two copies of the same chromosome remain attached to each other.
single-nucleotide polymorphisms
Replacement of a single nucleotide with another, producing variation within a species. These are often found in non-coding regions of DNA
genome sequencing
The process of determining the order of the bases in an organism’s genetic code.
binary fission
The process by which prokaryotes reproduce. The cell grows and then splits into two, having copied and distributed the DNA of the original cell into each newly formed cell.
DNA barcode
A method of environmental sampling that allows for the identification of species and the determination of biodiversity from traces of DNA.
dichotomous key
A tool used to identify species found in the field based on observations. A series of questions with two possible answers that leads to the correct identification of a species.
classification
A system of organising knowledge on all living things based upon their characteristics and more recently their DNA.
nomenclature
System or procedure of assigning names to groups of organisms.
Carl Linnaeus
Swedish botanist, zoologist, taxonomist and physician who formalised binomial nomenclature, the modern system of naming organisms and is known as the ‘father of modern taxonomy’.
taxonomy
The science of categorisation or classification.
mimicry
When a species evolves characteristics that resemble another organism, gaining some advantage.
hierarchical
Of the nature of a hierarchy; arranged in order of rank.
molecular clock
The technique that uses the mutation rate of biomolecules to deduce the time since two species shared a common ancestor.
genome size
Amount of DNA contained in a genome expressed in terms of the number of base pairs, kilobases or megabases, or as the mass of DNA in picograms.
diverged
One original species separating (diverging) into two (or more) new species.
cladograms
A diagram used in cladistics to show relations among organisms.
root
The initial ancestor common to all organisms in a cladogram.
node
A branching point of a cladogram representing a common ancestor.
terminal branch
Extant species at the ends of the branches of a cladogram.
