Chpt.2: The Characteristics of life

Living Things Microscopic Bacteria Plankton Amoeba Larger Moulds & Mushrooms (fungi) Trees, shrubs etc. (flowering plants) Dogs, cats, insects (animals) Characteristics of Life Organisation Nutrition Excretion Sensitivity/Behaviour Reproduction

Metabolism Metabolism: - is the sum of all the chemical reactions that take place in an organism e.g. includes growth, movement, excretion etc. - metabolic reactions are controlled by chemicals called enzymes. High Metabolic Rate: - fast acting e.g. mice, rabbits Low Metabolic Rate: - low acting e.g. koalas

Continuity of Life (Biogenesis) Continuity of Life : means that living things arise from other living things of the same type. y ou need reproduction and heredity to achieve continuity. a ll living things reproduce.

Life Life: is defined as the possession of ALL of the five characteristics of life: 1.Organisation 2.Nutrition 3.Excretion 4.Sensitivity/Behaviour 5.Reproduction is something that all living things have. it is very difficult to quantify.

The five characteristics allow organisms to carry out all the reactions necessary to survive and reproduce. We can recognise in living things the five characteristics that do not apply to non- living things.

1. Organisation Organisation: basic organisational feature of life is that living things are composed of cells. Organisms are organised as follows: Cells Tissues Organs Systems Organism

1. Organisation Structure relates to function therefore if any of the above structures is damaged there is a loss of some basic function.

2. Nutrition Nutrition: the way organisms obtain and use food. Sources of Nutrition: Plants, algae, some bacteria and plankton make their own food using the energy of the sun – photosynthesis. Animals, fungi, amoeba and most bacteria feed on other organisms. Sun: is the basic source of energy for all nutrition

3. Excretion Excretion: is the removal of waste products of metabolism from the body. Plants – less need for excretion - excrete waste gases through openings called stomata on the underside of their leaves. Animals – transfer waste internally from their cells to the blood. - blood carries the waste to the structure that removes it from the organism.

4. Response/Behaviour Response/Behaviour: is the way in which all living things react to changes (stimuli) in their environment. Animals – rapid and usually obvious response to stimuli e.g. light, temperature, pressure, sound. Plants – slower and less obvious responses.

5. Reproduction Reproduction: is the production of new individuals in order for the species to survive. Asexual Reproduction: produces exact copies of the parent e.g. Bacteria, protists or single-celled organisms. Sexual Reproduction: involves fertilisation of gametes from two parents and produces offspring that are slightly different to their parents.

Living VS Non-Living Living Things must display all five of these characteristics in order to be defined as living.