A3 Unity and Diversity : Organisms

Question 1

species

Answer 1

A group of similar organisms capable of breeding and producing fertile offspring.

Question 2

binomial nomenclature

Answer 2

Naming system for living organisms using two names for each species; the genus followed by the species.

Question 3

sexual dimorphism

Answer 3

When the male and female of a species look significantly different. Often having completely different features and appearance.

Question 4

interbreeding

Answer 4

Breeding between species. Produces infertile hybrid offspring.

Question 5

autosomes

Answer 5

Chromosomes that do not play a role in determining the biological sex of an organism.

Question 6

diploid cell

Answer 6

Cells that contain two copies of each autosome and two sex chromosomes. Diploid cells have an even number of chromosomes.

Question 7

speciation

Answer 7

The formation of new species by the splitting of one pre-existing species into two or more new species.

Question 8

karyotyping

Answer 8

Determining or analysing the karyotype (number, size and shape of the chromosomes) of an individual.

Question 9

karyogram

Answer 9

The image created by sorting, matching and aligning the chromosomes of an individual allowing for the visual interpretation of the chromosome characteristics.

Question 10

centromere

Answer 10

Central region of a chromosome pair where two copies of the same chromosome remain attached to each other.

Question 11

single-nucleotide polymorphisms

Answer 11

Replacement of a single nucleotide with another, producing variation within a species. These are often found in non-coding regions of DNA

Question 12

genome sequencing

Answer 12

The process of determining the order of the bases in an organism’s genetic code.

Question 13

binary fission

Answer 13

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.

Question 14

DNA barcode

Answer 14

A method of environmental sampling that allows for the identification of species and the determination of biodiversity from traces of DNA.

Question 15

dichotomous key

Answer 15

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.

Question 16

classification

Answer 16

A system of organising knowledge on all living things based upon their characteristics and more recently their DNA.

Question 17

nomenclature

Answer 17

System or procedure of assigning names to groups of organisms.

Question 18

Carl Linnaeus

Answer 18

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’.

Question 19

taxonomy

Answer 19

The science of categorisation or classification.

Question 20

mimicry

Answer 20

When a species evolves characteristics that resemble another organism, gaining some advantage.

Question 21

hierarchical

Answer 21

Of the nature of a hierarchy; arranged in order of rank.

Question 22

molecular clock

Answer 22

The technique that uses the mutation rate of biomolecules to deduce the time since two species shared a common ancestor.

Question 23

genome size

Answer 23

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.

Question 24

diverged

Answer 24

One original species separating (diverging) into two (or more) new species.

Question 25

cladograms

Answer 25

A diagram used in cladistics to show relations among organisms.

Question 26

root

Answer 26

The initial ancestor common to all organisms in a cladogram.

Question 27

node

Answer 27

A branching point of a cladogram representing a common ancestor.

Question 28

terminal branch

Answer 28

Extant species at the ends of the branches of a cladogram.