1. The Science of Life (pp. 2-12)

Biology

The science of life involving the study of living things and the theories that describe the world of life

“biology”

The word came from the Greek terms bios and logos

bios

Greek term meaning “life”

logos

Greek term which means “knowledge”

Biologist

Scientists who study living things

1. What is life

2. Differences between living and non-living things

3. Their types

4. Their functions

Organism

Refers to a living thing and:

1. What are they made up of

2. What are its functions

3. How does the organism live and breathe

4. Its interactions with its environment

Characteristics of Life

1. Cells

2. Nutrition

3. Respiration

4. Excretion

5. Growth and Development

6. Movement

7. Reproduction

8. Sensitivity

9. Adaptability

1. Cells

• These are simple units that make up organisms and they carry out activities necessary for the organism to stay alive

• Ex. Leaf cells in plants carry out photosynthesis

• Non-living things are not made up of cells

2. Nutrition

• The process by which organisms take in food and convert it into new protoplasm

• Organisms gain the energy and materials they need from their food since they all need energy to stay alive

Protoplasm

The living matter in the cells of the bodies of living things

Photosynthesis

Plants take in raw materials (CO2 and H2O) to make their own food

3. Respiration

Living things gain energy through the process of the oxidation of food substances to release energy for cell activities

4. Excretion

The process by which the organism removes metabolic waste products

Metabolic reactions

These are the chemical reactions that take place in living cells

Metabolism

It is the sum of all the biochemical reactions that take place within the cell

Excretory Products

The substances that are to be removed like carbon dioxide, water, mienral salts, and nitrogenous

5. Growth and Development

Growth is a permanent increase in the mass and volume of an organism when absorbed food is converted into living matter (protoplasm)

Development may make an organism more complex or even change its form

“organic”

This term refers to a compound that contains the element carbon

6. Movement

This is the motion of living things from oen place to another

Locomotion

The movement of animals from one place to another

7. Reproduction

In this process, some characteristics are passed on from the parents to their offspring and this is necessary to counter death and esnure survival

Species

This refers to a group of similar organisms

8. Sensitivity (Irritaiblity)

A change in the environment or an external influence causes the organisms to react in a predictable way and this is the response of living things to a stimulus

Stimulus (plural: stimuli)

A change or external influence

Response

The reaction of an organism to a stimulus

9. Adaptability

It is any characteristic of an organism that improves its chances of surviving in its environment

Classification

Biologists use this system of grouping according to their similarities and differences to study living things

Carolus Linnaeus

A Swedish naturalist in 1753 devised a system of classification

Artificial Classification

The type of classification where organisms can be grouped according to properties that are meaningful to humans (lacks connection)

Natural (Biological) System of Classification

The system biologists use is based on similarities and differences between organisms

Biological System of Classification

Organisms are first divided into five kingdoms:

1. Prokaryote

2. Protoctista

3. Fungi

4. Plantae

5. Animalia

1. Prokaryote

Bacteria

2. Protoctista

A collection of single-celled organisms and some multicellular ones, such as seaweeds

3. Fungi

Mushrooms, toadstools, and moulds

4. Plantae

Green plants

5. Animalia

The animal kingdom, which includes human beings

Hierarchy

The graded scale by which organisms are classified into

Viruses

The smallest “organisms” that are on the borderline between living and non-living things

Binomial System for Naming Species

Carolus Linnaeus used Latin to give each organism a name:

1. Genus with a capital letter

2. Species with small letters and italicised or underlined (Felis domestica)