Growth and Development

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Growth and
Development
Part 2
Learning Objectives
• To learn about the shape of growth
curves.
• To learn about how animals and plants
grow.
• To learn about how to measure growth
using different techniques.
Success Criteria
• I can interpret graphs and data on growth
in animals and plants.
• I can state the main difference between
growth in animals and plants.
• I can explain the advantages and
disadvantages of measuring the dry and
wet masses of organisms.
Starter: Development
The growth stages the girl went through in the video
were:
infancy  childhood  adolescence
What other developmental stages will she go through in
her life?
Adulthood

Are all developmental
stages the same length?
No. Adulthood is longest.
During which one is
growth rate quickest?
Infancy.
Old-Age

What type of cell division
results in growth?
Mitosis.
Growth
• Unlike plants, animals only grow in the early stages of
their lives.
220
200
male
female
Height (cm)
180
160
140
120
100
80
60
40
20
0
0
2
4
6
8
10
12
14
16
18
20
22
24
Age (years)
• After the age of around 18-23, there is no more
growth.
• Cells only divide for repair after this time.
Animal Growth
• Animals grow to a maximum size and then stop.
A humans maximum height
is determined by genes and
the environment.
All parts of an animal grow
and the whole body gets
bigger.
Onwards and
Upwards
(+ outwards)
Answer question 8 in the new student
textbook (pg. 34)…
Make sure you read the
axes carefully! The graph
in this question is not the
same type as seen earlier!
Answers:
8a 14–16
8b Growth stops
8c Approx. 9–13
Plant Growth
• Plants grow very differently from animals.
• Plant’s don’t have a maximum size and can continue
to grow.
Cell division only takes
place in special areas
called meristems.
Meristems are found
at the tips of the
shoots and roots.
All other cells in a
plant simply elongate
rather than divide.
Many plant cells retain the ability to
differentiate, unlike animal cells
Measuring Growth
• The growth of both animals and plants can be
measured by measuring increase in mass.
• There are two ways to do this. Measuring:
Wet Mass:
This is the mass of the whole
organism and can be measured
when the organism is alive.
Dry Mass:
This is the mass of an organism
with water removed. The
organism must be dead.
Use the graph below to answer Questions
9-11 in the textbook (pg. 35):
ANSWERS:
9a - 2
9b - Lack of space, water
or minerals
10 - To measure dry mass
you need to kill the
organism
11 - Growth is all over the
human body but mainly
in the meristems of the
tree, tree continues to
grow humans reach a
finite size
HIGHER
GROWTH OF A BABY
Complete Mini-Worksheet 3
• Use the purple section of page 35 to complete
worksheet 3.
ANSWERS:
1. Table should be filled in the same as on page 35.
2. The growth rate of the root tip is much greater
because the root tip contains the meristem. This is
where cell division occurs. The rest of the plant
grows slower, because cells elongate rather than
divide.
EXTENSION:
Answer questions 12-14.
Measuring Growth
• We grow very differently from plants because we only
have two growth phases.
• One just after birth and one during adolescence.
All parts of a child grow quite evenly
during childhood.
However, this isn’t the case before birth,
when the BRAIN grows much quick than
any other body part…
Baby’s Brain
• In the womb, the head a of a baby grows faster than
any other part.
• The growth of the brain is a
priority.
• It has to grow quickly so that
it can coordinate the rest of
the human structure.
Click to play video about foetal
brain development
PLENARY
Plenary: Babies
Using a white board or your book, draw the changes in
the head and body size of a foetus as it grows.
Your last drawing should be of the new born baby.
Explain why the size of the head changes so much
quicker than the body.
Learning Objectives
• To learn about the shape of growth
curves.
• To learn about how animals and plants
grow.
• To learn about how to measure growth
using different techniques.
Success Criteria
• I can interpret graphs and data on growth
in animals and plants.
• I can state the main difference between
growth in animals and plants.
• I can explain the advantages and
disadvantages of measuring the dry and
wet masses of organisms.
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