1. Ch 2. The Characteristics of Life

2. 1.2.2 Definition of Life

3. Need to know Define the term ‘Life’
Define the terms – Metabolism & Continuity of life
List the 5 "characteristics of life",
Define nutrition, excretion, response and reproduction.

4. Life
involves the interaction of the characteristics of life.

5. What makes Plants & Animals ‘living’?
Do they have common features?
Do they have common behaviours?

6. Common Characteristics
Living things:
are highly organised
are composed of tiny units called cells
grow
excrete
move
react to their surroundings
feed
reproduce

7. Metabolism METABOLISM
Metabolism refers to the chemical reactions that occur in the cells of organisms.
These reactions are responsible for the process of
Growth
Repair
Responsiveness
Reproduction

8. Continuity of Life
Continuity of life is the ability of an organism to exist from one generation to the next.
You need reproduction and heredity to achieve continuity.
Genes are hereditary factors that are passed on from one generation to the next during reproduction.

9. Learning check Explain the term Metabolism.
Metabolism refers to the chemical reactions that occur in the cells of organisms.
Explain the term ‘Continuity of Life’.
Continuity of life is the ability of an organism to exist from one generation to the next.

10. How do we know if something is alive?
It has organization – cells, tissues, organs, etc.
It uses energy
Grows and develops
Excretes
Reproduces
Responds to the environment
Adapts to the environment

11. Organisation The Cell is the basic unit of all living organisms
Specialized structures
Unicellular or multicellular
If cell structure is damaged its function is also affected

12. Levels of organisation
Cell
Tissue
Organ
Organ system
Organism
Population
Community
Ecosystem
Biosphere

13. The Cell: High School Biology
This animation shows the structure and function of plant and animal cells for high school biology, including organelles like the nucleus, nucleolus, DNA (chromosomes), ribosomes, mitochondria, etc. Also included are ATP molecules, cytoskeleton, cytoplasm, microtubules, proteins, chloroplasts, chlorophyll, cell walls, cell membrane, cilia, flagellae, etc.
7.21mins

14. Energy
All energy for living things can be traced back to the sun (primary source of energy)
Organisms use light energy to
see (vision),
to make food (plants use sunlight during photosynthesis),
for warmth (organisms eat the plants to get energy during respiration

15. ENERGY FLOW

16. PHOTOSYNTHESIS

18. Learning check It has organization – cells, tissues, organs, etc.
How do we know something is alive?
It has organization – cells, tissues, organs, etc.
It uses energy
Grows and develops
Excretes
5. Reproduces
6. Responds to the environment
7. Adapts to the environment

19. Growth and Development
Growth – increase in size
Development – change in form or shape
Amount of growth varies in different organisms
Nutrition maintains the organisation and growth of living organisms

20. Nutrition
This is the process involved in the intake and use of energy and materials from the environment.

21. Sources of Nutrition
In Plants: Autotrophs - make food by photosynthesis and absorbing chemicals from the environment . In Animals: Heterotrophs - feed on other organisms Energy flow: Sun  Plants Animals

22. Excretion
Excretion - is the removal of wastes made in the body cells e.g. Urea, carbon dioxide and water.
All living things must get rid of waste material – if it was allowed to accumulate it would become toxic to the organism
A balance must be maintained between their internal and external environments

23. Methods of excretion Various organised structures involved
In Animals: the urinary system, skin, lungs
In Plants: the stomata

24. Learning check
1. What is meant by nutrition?
This is the process involved in the intake and use of energy and materials from the environment.
2. What is meant by Excretion?
Excretion - is the removal of wastes made in the body cells e.g. Urea, carbon dioxide and water.

25. Response and Adaptation
Response is the ability of an organism to react to changes both inside and outside their bodies.
Adaptation – plants and animals change in response to long-term changes in the environment; these may be passed on to future generations (Charles Darwin)

26. Methods of response
In Animals: organised structures respond to light, sound, touch, etc.
In Plants: growth towards or away from a stimulus e.g. light, water, fertilisers, etc.

27. Reproduction
Reproduction is the ability of an organism to produce new individuals of its own kind.
Life comes from life.
Necessary for the survival of the species
Offspring can be genetically the same as or different from parent(s).

28. Methods of reproduction
Asexual: involves only one parent e.g. in bacteria and protista divide from one cell into two - binary fission. During mitosis one cell divides into two e.g. in plants and animals.
Sexual: involves two parents and the production of male and female gametes e.g. in plants and animals.

29. Learning check What is meant by response?
Response is the ability of an organism to react to changes both inside and outside their bodies.
What is meant by reproduction?
Reproduction is the ability of an organism to produce new individuals of its own kind.
3. Name the methods of reproduction and explain.
Asexual: involves only one parent . Sexual: involves two parents and the production of male and female gametes.

30. http://nortonbooks.com/college/biology/ani mations/ch01a02.htm

31. END