Classification and variation

Chapter 7Biology

(2nd week)

Animal kingdom

VertebratesInvertebrates

Jellyfish

Flatworms

Annelid worms

Nematode worms

ArthropodsMolluscsEchinode

rms

ArachnidsInsectsCrustace

ansMyriapo

ds

Birds ReptilesAmphibians MammalsFish

- Each class of vertebrates is divided into smaller groups called order.

- There are 19 orders of mammals.- Four orders are shown below.

Mammals

WhalesRodentsBatsInsectivores

- Flipper.- Tail with fins.

- Chisel-like teeth for gnawing.

- Small body.- Wings.

- Small body.- Long snout.

- An order is made of smaller groups called families.- The member of families seem similar but there are

differences.Example:Whales

White WhaleDolphinSperm

WhaleBeaked whale

- No back fin.- Blunt snout.

- Sickle shaped flippers and back fin.

- Large head.- Rounded back

fin.- Few teeth.- Small flippers.

Plant kingdom

ConifersFernsLiverworts and

mossesFlowering plantsAlgae

1) Algae- Simple plants- No roots, stems or leaves but they contain chlorophyll

(green pigment).- Seaweeds (largest species) of algae have red and

brown pigments.

- Most species of algae are so small they can only be seen with a microscope.

- When they occur in large numbers, they can be clearly seen and they turn pond water green.

2) Liverworts and mosses

- Liverworts are small plants that do not have true roots, stems or leaves.

- They grow in damp places near streams and ponds.

- Mosses have stems and leaves but they do not have proper roots

- Moss plants are usually found growing together, in many different habitats from dry walls to damp soil.

- Both liverworts and mosses reproduce by producing spores.

- They make spores in a capsule that is raised into the air.

- When the capsule opens the spores are carried away by air currents.

3) Ferns- Ferns have true roots and stems and reproduce by making spores.

- The feather like leaves are called fronds.

- The spores are made in structures called sporangia on the underside of the fronds.

4) Conifers

- A conifer has roots, a woody stem and needle like leaves.

- Most conifers lose and replace their leaves all year round, so they are called evergreen.

- Almost all conifers reproduce by making seeds that develop in cones.

- When the seeds are ready to be dispersed the cones open and the seeds fall out.

- Each seed has a wing that prevents the seed falling quickly and allows it to be blown away by the wind.

5) Flowering plants- Has root, stem and leaves.- In some plants the stem is

woody.- All of the flowering plants

reproduce by flowering and making seeds.

There are lots of differences between these organisms.

For example: some have leaves; some lay eggs; some eat plants.

These organisms are different because they are all from different species.

Spot the differences

There are also differences between organisms of the same species.

For example, these people are all from the same species but how many differences between them can you spot?

Spot the differences – same species

Even though people are all from the same species, there are many ways in which they are different from each other.

Some of them are male, some are female, some are tall, some are short.

The differences that occur both between different species and within the same species are called variation.

What is variation?

- The causes of variation

Environment Lack of mineralsEx. Soil can affect the colour and structure of the leaves.- The presence of lime in the soil can affect the colour of hydrangea flower (produces litmus)If the soil has lime the flowers are pink, if it is lime free flowers are blue.- If flamingoes eat shrimps that have a pink pigment the feathers become pink.

Ex. If some seedlings are grown in the dark and some in the light

they will have different features.

Food an animal eatsEx. If environment does not eat food,

adult animals become thin and have smaller

body mass.