Biology - Unit 2: Classification

How can organisms be classified into groups?

based on the features that they share

What is a species?

a group of organisms that can reproduce to produce fertile offspring

What is the binomial system of naming species?

an internationally agreed system in which the scientific name of an organism is made up of two parts showing the genus and species

what is the main features of animals?

• multicellular

• contains nucleus but cell walls and chloroplasts are absent

• feed on organic substances made by other living things

what are the main features of plants?

• multicellular

• cells contain a nucleus, chloroplasts and cellulose cell walls

• feed by photosynthesis

what are the main features of fungi?

• usually multicellular

• cells have nuclei and cell walls made from chitin

• do not photosynthesise but feed by saprophytic (on dead or decaying material) or parasitic (on live material) nutrition

what are the main features of protocists?

• most are unicellular but some are multicellular

• all have a nucleus, some may have cell walls and chloroplasts

• some protocists photosynthesise and some feed on organic substances made by other living things

what are the main features of prokaryotes?

• often unicellular

• cells have cell walls made of peptidoglycan and cytoplasm but no nucleus or mitochondria.

what are the main features of mammals?

• fur/hair on skin

• give birth to live young

• have placenta

• produces milk to feed young

• external ears visible

• endothermic

what are the main features of birds?

• feathers cover skin

• have 2 legs and 2 wings, instead of forelimbs

• lay eggs with hard shell on land

• have a beak

• endothermic

what are the main features of reptiles?

• dry, fixed scales on skin

• lay eggs with rubbery shell on land

• cold-blooded

what are the main features of amphibians?

• smooth, moist skin

• lays eggs without shells in water

• adults live on land (no gills), larvae live in water (have gills)

• cold-blooded

what are the main features of fish?

• loose, wet scales on skin

• lays eggs without shells in water

• gills to breathe

what are the main features of myriapods?

• body consists of many segments

• each segment contains at least one pair of jointed legs

• one pair of antennae

what are the main features of insects?

• 3 part body: head, thorax, abdomen

• 3 pairs of jointed legs

• 2 pairs of wings (may be non-functional and/or underdeveloped)

• one pair of antennae

what are the main features of arachnids?

• 2 body parts: cephalothorax and abdomen

• 4 pairs of jointed legs

• no antennae

what are the main features of crustaceans?

• more than 4 pairs of jointed legs

• chalky exoskeleton formed from calcium

• breathe through gills

• 2 pairs of antennae

what are the main features of ferns?

• have leaves called fronds

• don’t produce flowers but reproduce by spores produced on the underside of fronds instead.

what are the main features of flowering plants?

• reproduce sexually by means of flowers and seeds.

• seeds are produced inside the ovary found at the base of the flower

• can be divided into 2 groups — monocotyledons and dicotyledons

what are the main features of monocotyledons?

• flowers of monocotyledons contain petals in multiples of 3.

• leaves from monocotyledons have parallel leaf veins.

what are the main features of dicotyledons?

• flowers from dicotyledons contain petals in multiples of 4 or 5.

• leaves from dicotyledons have reticulated (branched) leaf veins

where can viruses replicate?

viruses can ONLY replicate in living cells.

what are the main features of viruses?

• genetic material (RNA or DNA)

• protein coat

• outer envelope