WHAT IS BIOLOGY Biology is the study of

WHAT IS BIOLOGY?

Biology is the study of all living things. From microscopic bacteria to the largest animal on Earth.

Living things are called organisms.

Living things are found everywhere in our biosphere. • The biosphere is all organisms and the parts of the Earth where they are found.

Organisms can be found …in the air

…in the soil

…in boiling hot springs bacteria

…. in the deepest oceans

The variety of life is called biodiversity.

There are 1. 6 million species described on Earth. GROUP Described species Likely total Insects 950, 000 8, 000 Fungi 70, 000 1, 000 Arachnids 75, 000 750, 000 Viruses 5, 000 500, 000 Nematodes 15, 000 500, 000 Bacteria 4, 000 400, 000 Vascular plants 250, 000 300, 000 Protozoans 40, 000 200, 000 Algae 40, 000 200, 000 Mollusks 70, 000 200, 000 Crustaceans 40, 000 150, 000 Vertebrates 45, 000 50, 000

But…… the estimated amount is 12, 000 species. NO WAY!!!!

What is a species? A species is a particular type of organism that can reproduce by interbreeding among themselves and produce fertile offspring.

Male donkey + female horse = mule + = infertile Different species

Characteristics of Living Things All organisms share certain characteristics.

Cells: All organisms are made up of one or more cells.

A cell is the basic unit of life. Plant cell Animal cell

Need for energy: All organisms need energy to power their life processes, such as metabolism, movement, growth, repair, and reproduction. Metabolism is all the chemical reactions that build up or break down materials.

Some organisms, such as animals, get energy by eating other organisms.

Some organisms, such as plants, absorb energy from sunlight and absorb energy from sunlight store it in compounds for later use.

Respond to environment: All organisms must react to their environment or respond to stimuli. A stimulus is a physical or chemical change in the internal or external environment.