Edexcel GCSE Combined Science Biology Topic 4

Ardi

Nickname for a 4.4-million-year-old fossilised specimen of Ardipithecus ramidus.

binomial system

System of naming organisms using two Latin words.

evolution

A change in one or more characteristics of a population over a long period of time.

Lucy

Nickname for a 3.2-million-year-old fossilised specimen of Australopithecus afarensis.

species

A group of organisms that can reproduce with each other to produce offspring that will also be able to reproduce. Organism names have two Latin words - the first is its genus and the second is its species.

ancestor

An organism from which more recent organisms are descended.

antibiotic

Medicine that helps people recover from a bacterial infection by killing the pathogen.

competition

There is competition between organisms that need the same things as each other (such as food). We say that they 'compete' for those things.

genetic variation

Differences between organisms caused by differences in genes and passed on to offspring by their parents through reproduction. Also called inherited variation.

natural selection

A process in which certain organisms are more likely to survive and reproduce than other members of the same species, because they possess certain genetic variations.

resistant

Unaffected or less affected by something.

classification

Sorting things into groups.

domain

The three main groups that organisms are now sorted into: Archaea, Bacteria and Eukarya.

genus

A group of similar organisms. The genus name is the first word in the scientific name for a species (the second word is the 'species name'). Different closely related species belong to the same genus.

kingdom

There are five kingdoms into which organisms are divided: plants, animals, fungi, protists and prokaryotes.

species

A group of organisms that can reproduce with each other to produce offspring that will also be able to reproduce. Organism names have two Latin words - the first is its genus and the second is its species.

artificial selection

When people choose organisms with certain characteristics and use only those ones for breeding.

breed

Group of animals of the same species that have characteristics that make them different to other members of the species.

disease resistance

Unaffected or less affected by a certain disease.

gene

Section of the long strand of DNA found in a chromosome, which often contains instructions for a protein.

genetic engineering

Altering the genome of an organism, often by adding genes from another species. Also called genetic modification.

genetically modified organism (GMO)

Organism that has been produced using genetic engineering.

genome

All the DNA in an organism. Each body cell contains a copy of the genome.

GMO

Short for 'genetically modified organism'.

selective breeding

When humans choose an organism that has a certain characteristic and then breed more of these organisms, making that chosen characteristic more and more obvious.

variety

Group of plants of the same species that have characteristics that make them different to other members of the species.

yield

The amount of useful product that you can get from something.

allele

Most genes come in different versions, called alleles. So a gene for eye colour may have a version (allele) that can cause dark eyes and an allele that can cause pale eyes.

base

There are four substances called bases that help make up DNA, often shown by the letters A, C, G and T. Pairs of bases form 'links' between two 'spines' formed of phosphate groups and a type of sugar.

diabetes

Disease in which the body cannot control the blood glucose concentration at the correct level.

insulin

The hormone that decreases blood glucose concentration. Used in the treatment of type 1 diabetes.

ligase

An enzyme that joins two DNA molecules together.

plasmid

A small loop of DNA found in the cytoplasm of bacteria.

recombinant DNA

DNA made by joining two sections of DNA together.

restriction enzyme

An enzyme that cuts DNA molecules into pieces.

sticky end

A short section of single-stranded DNA found at the end of a section of DNA that has been cut by a restriction enzyme.

type 1 diabetes

Type of diabetes in which the pancreas does not produce insulin.

vector

Anything that transfers material from one organism to another.