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Lecture

measurement


Department
Biology
Course Code
BIOL 1602
Professor
Rebecca Jubis

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Growth And Its Measurement
Methods Of Measuring Growth
Human growth is diffuse (→spread throughout)
o Adult is taller, larger from front to back, has larger organs than a child
Growth: permanent increase in amount of organic matter
o Produces new cells and increases size of existing cells
o Somatotropin (→growth hormone) stimulates cell division, protein synthesis /
released by anterior lobe of pituitary gland
o Monitored by standing height and body mass
Development: physical, emotional, mental, social changes throughout live
Supine Length (unable to stand → infant's length)
Infant is placed, on it's back, on a table
Ankles are gently pulled to straighten infant's leg
Length is measured from top of its head to base of its heels
Standing Height
Person standing with their heels flat on the ground
Horizontal bar is moved to touch the top of the person's head
Body Mass → Amount of Organic Matter [Dry Mass → Plants]
Wet body mass (weight) in humans is an INDICATION of organic matter
Includes food + H2O → method can be misleading
Absolute Growth and Growth Rate
ABSOLUTE GROWTH: total growth / cumulative height of a person
o [GRAPH] Regular increase in size that levels out at ≈16 years
GROWTH RATE: increase (in an appropriate feature) per unit time
o GROWTH RATE = (SIZE AT T2 - SIZE AT T1) / (T2-T1)
o Highest in the first year
o Decreases rapidly during the first 2 years
o Constant, low rate during childhood
o Females and males have similar height until ≈14 → growth spurt occurs
later but greater in males than in females
Therefore, male becomes taller than the female at ≈14
o Growth stops by the age of ≈18
Advantages and Disadvantages of Cross-Sectional Study
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