The Five Kingdoms (Cambridge O Level Biology)

• The first division of living things in the classification system is to put them into one of five kingdoms. They are:
  • Animals
  • Plants
  • Fungi
  • Protoctists
  • Prokaryotes

• Main features of all animals:
  • they are multicellular
  • their cells contain a nucleus but no cell walls or chloroplasts
  • they feed on organic substances made by other living things

A typical animal cell

• Main features of all plants:
  • they are multicellular
  • their cells contain a nucleus, chloroplasts and cellulose cell walls
  • they all feed by photosynthesis

A typical plant cell

• Main features of all fungi (e.g. moulds, mushrooms, yeast)
  • usually multicellular
  • cells have nuclei and cell walls not made from cellulose
  • do not photosynthesize but feed by saprophytic (on dead or decaying material) or parasitic (on live material) nutrition

A typical fungal cell

• Main features of all protoctists (e.g. Amoeba, Paramecium, Plasmodium)
  • most are unicellular but some are multicellular
  • all have a nucleus, some may have cell walls and chloroplasts
  • meaning some protoctists photosynthesise and some feed on organic substances made by other living things

Two examples of protoctist cells

• Main features of all prokaryotes (bacteria, blue-green algae)
  • often unicellular
  • cells have cell walls (not made of cellulose) and cytoplasm but no nucleus or mitochondria

 

A typical bacterial cell

• Several main features are used to place organisms into groups within the animal kingdom

Vertebrates

• All vertebrates have a backbone
  • There are 5 classes of vertebrates

Class	Main Features	Examples
Mammals	Fur/hair on skin Gives birth to live young Have placenta Produces milk to feed young External ears visible Endothermic	Human, dog, mouse, horse
Birds	Feathers cover skin Have two legs and two wings, instead of forelimbs Lay eggs with hard shell on land Have a beak Endothermic	Eagle, hen, duck, pigeon
Reptiles	Dry, fixed scales on skin Lay eggs with rubbery shell on land	Snake, lizard, turtle
Amphibian	Smooth, moist skin Lays eggs without shells in water Adults live on land (no gills), larvae live in water (have gills)	Frog, toad, newt
Fish	Loose, wet scales on skin Lays eggs without shells in water Gills to breathe	Flounder, tuna, clown fish

 

Vertebrate classification

Invertebrates

• Invertebrates do not possess a backbone
• One of the morphological characteristics used to classify invertebrates is whether they have legs or not
• All invertebrates with jointed legs are part of the phylum Arthropods
• They are classified further into the following classes:

Invertebrate Table 

Class	Main Features	Example
Myriapods	Body consists of many segments Each segment contains at least one pair of jointed legs One pair of antennae	Centipede
Insects	Three part body: head, thorax, abdomen Three pairs of jointed legs Two pairs of wings (these may be non-functional and/or underdeveloped) One pair of antennae	Butterfly, ant, wasp
Arachnids	Two body parts: Cephalothorax and abdomen Four pairs of jointed legs No antennae	Spider, scorpion, tick
Crustaceans	More than four pairs of jointed legs Chalky exoskeleton formed from calcium Breathe through gills Two pairs of antennae	Crab, lobster

  Arthropod classification

• At least some parts of any plant are green, caused by the presence of the pigment chlorophyll which absorbs energy from sunlight for the process of photosynthesis
• The plant kingdom includes organisms such as ferns and flowering plants

 Ferns

• Have leaves called fronds
• Do not produce flowers but instead reproduce by spores produced on the underside of fronds

Ferns reproduce by spores found in the underside of their fronds

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 two groups – monocotyledons and dicotyledons

Wheat plants are monocotyledons

Sunflowers are dicotyledons

How do you distinguish between monocotyledons and dicotyledons?

1) Flowers

• Flowers from monocotyledons contain petals in multiples of 3
• Flowers from dicotyledons contain petals in multiples of 4 or 5

2) Leaves

• Leaves from monocotyledons have parallel leaf veins
• Leaves from dicotyledons have reticulated leaf veins (meaning that they are all interconnected and form a web-like network throughout the leaf)

Comparing monocots and dicots