Exam 3 Flashcards
What does the sigmoidal curve represent
It shows cumulative weight is expressed as total weight at any given time
What does the sigmoidal curve look like
Shaped like the letter S and has a stair stepped appearance due to sporadic growth spurts
What is the self accelerating phase of growth
Characterized by exponential growth due to each cell dividing into two daughter cells at a constant rate resulting in rapid growth w/ little complexity
Why does velocity of growth continue to increase during the self accelerating phase
Because there are more and more cells available to divide
Why does the growth rate of the self accelerating phase begin to slow down
Because it becomes difficult to supply each cell w/ nutrients and efficiently remove harmful wastes
What happens when there is a decrease in efficiency during the self accelerating phase
There is an increase in complexity of the cells
How does the embryo respond during the self accelerating phase
By developing increasingly complex transport mechanisms to supply nutrients and removes waste
When does growth become linear
When the acceleration force is in balance w/ the counteracting effects of increased complexity and limited nutrients
What is the point of inflection
The point of maximum growth velocity after which the animal will continue growing but at a decreasing rate
What is another way to look at the maximum growth velocity
It is the period of greatest average daily gain
When does point of inflection occur in many species
Puberty
What is the self decelerating phase
When the animal approaches mature weight at a decreasing rate of growth gradually diminishing the amount of feed intake until energy consumed approaches maintenance requirements
What is one thing that controls the growth rate
Secretion of somatostatin by the hypothalamus
What is asymptote phase
Point at which food intake matches maintenance requirement
What does excess in cells being produced result in during the asymptote phase
Adipose tissue
What fluctuates maintenance requirements once in the asymptote phase
Available food, reproductive cycle, and season
What is the the senescence and death phase
The eventual failure of vital systems results in the loss of body condition and death
When and why does the senescence and death phase typically occur
After the reproductive phase of life and to ensure space for the next generation
What is growth a function of
Chronological and physiological age
What type of growth curves describe growth over time
Cumulative growth, absolute growth, relative growth
What factors can influence the growth curve of chronological age
Nutrition, disease, stress, and activity level
What is important to keep in mind when looking at chronological age
That age is in absolute time units and that animals w/in a species, breed, or gender do not grow, develop, or fatten at the same rate or mature at the same chronological age
What is physiological age used for
Comparing different animals in various species
What does physiological age refer to
Specific physical or chemical stages of maturity including height, weight, composition, and puberty