Why do we classify organisms ?

There are millions of species on our planet. Although species can be very different from each other, many have similar features that allow us to put them into groups. This is called classification.

The first big division of living things in the classification system is to put them into one of five kingdoms. These are based on what an organism's cells are like.

The five kingdoms are:

1. Animals (all multicellular animals)

2. Plants (all green plants)

3. Fungi (moulds, mushrooms, yeast)

4. Protists (Amoeba, Chlorella and Plasmodium)

5. Prokaryote—bacteria (E.coli, slamonella)

Organelle specialised structure within a cell (eg, mito-

chondrion, nucleus, ribosome)

Nucleus the control centre of the cell, where the DNA

is stored

Mitochondria the site of aerobic respiration

Cell membrane controls what goes into and out of the cell

Cytoplasm the liquid gel in which most chemical reac-

tions take place

Cell wall made of cellulose and gives plant strength

Vacuole filled with cell sap. Keeps the cell rigid

Chloroplasts (green plant cells only - not roots) - site of

photosynthesis. Harvests light energy as they

contain chlorophyll

Prokaryote A single celled organism with no nucleus or

membrane bound organelles

Eukaryotes

Plant and animal cells

are both Eukaryotes.

Which means that the

cells contain a nucleus

and membrane bound

organelles

Plant cells

Plant cell s need to per-

form two functions not

performed by animal

cells:

1. produce their own

food.

2. Support their own

weight

Preparing and onion

cell slide

Cut open an onion.

Use forceps to peel a

thin layer

of epidermis from

the inside.

Lay the layer of epidermis on a microscope slide.

Add a drop of iodine solution to the layer.

Carefully place a cover slip over the layer.

The iodine solution stains starch in the cells blue-black,

making the cell features easier to see.

Magnification = eyepiece lens x objective lens

Palisade cells

Stomata and Guard cells

Specialised Plant cells

Tissues and Organs

Root Hair cell Plant Organs

Plant tissues

Xylem transports water and minerals

from the roots to the rest of the plant.

Phloem transports sugars made by

photosynthesis in the leaves to the rest

of the plant.