1. Understanding Animal Life Span Unit 3, Lesson 2

2. Life Span
Live span is the period of life for an organism. It is the length of time between birth and death.
Based on the average amount of time an organism lives
Humans = 75 years in U.S.
Cattle = years

3. Living Condition
Living condition: is the ability of an organism to carry out life processes, needed for protoplasm to function.
7 Processes needed to remain alive:
Getting and using food
Movement
Circulation
Respiration
Growth and repair
Secretion
Sensation
Some have 2 more processes
Reproduction
Lactation

4. The 5 Stages of Life
All organisms have a definite sequence of stages of life
A. Stages of Life: developmental periods with common characteristics that represent various conditions of the organism.
B. These stages are recognized in most animal’s lives.

5. Stage 1: Beginning The start of an organism’s life.
With mammals, begins with conception or birth, depending on calculation.
Age begins with day of birth.
Living organism starts forming at conception.

6. Stage 2: Growth The time following the beginning
Organism is rapidly increasing in size and developing skills.

7. Stage 3: Maturity The state when organism is fully developed.
Carries out functions of adults
No longer increases much in size
Have reached reproductive potential

8. Stage 4: Decline The stage of life that follows maturity
Organism has lived past maturity and begins to lose the ability to maintain itself
Cells are no longer repaired and replaced
Associated with aging

9. Stage 5: Death
Protoplasm in the cells of the organism cease to function.
Chemical activity in the cells stops
Organism is no longer alive.

10. C. An example: The Horse Stage 1: Conception
Stage 2: During the first 2-3 years of life
Stage 3: years following growth
Stage 4: Horse starts losing teeth, bone problems, deterioration
Stage 5: Death follows when horse stops breathing