Domains and kingdoms

What are the three domains?

Archaebacteria, eubacteria, eukaryota

What are archaebacteria?

Primitive bacteria, including extremophiles. They have no nucleus and their genes contain unused sections of genes

What are eubacteria?

True bacteria and cyanobacteria, which are able to synthesise. They have no nucleus but do not contain unused sections of genes

What are eukaryota?

Cells that contain a nucleus and unused sections of genes

What are the five kingdoms?

Prokaryotae, plantae, animalia, fungi, protoctista

What are phyla?

The division of each kingdom into groups which show individual characteristics

Examples of phyla in animalia

Arthropods (a huge group of animals including insects, crabs, spiders and centipedes), annelids (segmented worms including earthworms and leeches), chordates (vertebrates including bony fish, mammals, birds, reptiles)

Give an example of a class

Insecta

Give examples of orders

Orthoptera (such as locusts and grasshoppers)

What is the concept of a species?

When two organisms breed within a species, their genes pass to their offspring, creating a shared gene pool so members of the same species resemble each other

What is sexual dimorphism?

When different genders of the species look different from each other - e.g. male lions have manes but female lions do not

What happens when two members of a species reproduce?

They produce fertile offspring. But dissimilar organisms do not produce fertile offspring when they reproduce; this is due to differing numbers of chromosomes, incompatible physiology or biochemistry meaning that hybrids aren’t viable so any offspring will not be able to reproduce

How was the three domain system created?

Genetic sequencing created new ways of analysing organism relationships, suggesting that all organisms evolved along three different distinct lineages. Each domain has groups of organisms which show a distinct unique pattern of ribosomal RNA reflecting the closeness of their evolutionary relationships

What is an example of different domains having different ribosomal RNA?

70s (from eubacteria) and 80s (from eukaryota) ribosomes have different sizes so there must be differences in their RNA