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4.6
GROWTH IN
MULTICELLUL
AR
ORGANISMS
A series of changes in the life of an organism
–from zygote to adult – involves two major
processes:
(i) Growth
(ii) Devel...
Any irreversible and permanent increase in
quantitative parameters that can be measured
such as:
Growth Phases
Definition ...
Any qualitative change and involve cell
differentiation:
Growth Phases
Definition of Development
shape
specificity
complex...
Growth
Involves 3 processes:
• Cell division – mitosis
• Cell elongation
• Cell differentiation
Growth Phases
1. Cell Division
• mitotic cell division in all somatic cells
• Through mitosis, the number of cells increas...
Growth Phases
1. Cell Division
Plants – occurs in apical meristem (Root tip/shoot tip)
• Cells small, closely arranged, la...
Growth Phases
2. Cell Elongation
 Plants - cells elongate & expand due to:Plants - cells elongate & expand due to:
-- abs...
Growth Phases
3. Cell Differentiation
• the cell
undergoes change
in shape
 in order to
perform specialized
functions - s...
• e.g. : meristematic vascular cells
• the meristematic cells differentiate into:
 xylem: transportation of
water and min...
GROWTH OF CELLS
CELL DIFFERENTIATION
Guard cell
and stomata
Mesophyll
cell
phloem xylem Parencymatous
cell of cortex
Growth Phases
Plants – In Root Tip
Three phases / zones:
1. Cell divisions
2. Cell elongation
3. Cell differentiation
THE GROWTH ZONE IN A PLANT SHOOT
Zone of cell division/
growth zone
Zone of cell
elongation
Zone of cell
differentiation
M...
• Surface area of a leave
can be determine by
draw the outline of the
leave at a graph paper
or square paper (1cm x
1cm) a...
the more appropriate parameters for the
measurement of growth in multicellular
organisms are the weight or mass
Measuring ...
• Periodic linear measurementPeriodic linear measurement
Eg: Measuring height for human being –
the best way to measure th...
• the mass of the organism in the normalnormal condition
Measuring Growth
Fresh Mass
The advantages
• easier and convenien...
The disadvantages
• inaccurate and inconsistent
• because it is affected by the fluctuation of
the amount of water in the ...
• the mass of the organism after its water
content is fully eliminated
Measuring Growth
Dry Mass: Definition
• it implies ...
1. The specimen is destroyed…
Measuring Growth
Dry Mass: Methods
2. …then transferred into the oven at 110°C
to eliminate ...
Measuring Growth
Dry Mass
The advantages
• more accurate
• the amount of water in an organism is not
constant, i.e. depend...
Measuring Growth
Dry Mass
The disadvantages
• destruction of specimens
• in repeated measurement, specimens of the
similar...
If an organism’s measurements (height,
weight, etc) are plotted against time, a
growth curve is obtained.
GROWTH
CURVE
Sigmoid Curve
Maturity
phase
Senescence
& death
GROWTH STAGES
1. Lag phase:
(a)The beginning of the growth process
(b)The rate of growth is generally low
(c)Cell division...
3. Maturity Stage
a) Growth rate is low
b) Cells achieve the optimum size(adult)
and there is no more increase in size of
...
HUMANS GROWTH CURVE
VIDEO
GROWTH CURVE OF A HUMAN
GROWTH CURVE OF A HUMAN
Time / year
Growth ( height/
weight)
At birth
Rapid growth
Slow growth
Very rapid growth
Very litt...
GROWTH OF A BOY AND A GIRL
Rate of increase in height Kadar pertambahan berat
Age /
years
Height/cm
boy
girl
Freshweight
R...
GROWTH CURVE OF
INSECTS
VIDEO
Grasshoppers moult (shed skin) 5 times from 1st
instar to adult
Growth curve of insects
– staircase shape
PRIMARY &
SECONDARY
GROWTH IN PLANTS
VIDEO
Growth in Plant
Meristem
Actively dividing tissue.
• Apical meristem: These are found at the
tips of roots and shoots and are
responsible ...
Primary & Secondary Growth
• All plants exhibit primary growth
• Woody plants also undergo secondary
growth (increase in g...
Primary Growth
• Primary growth leads to an increase in length
of the plant shoots or roots.
• It is due to the activity o...
THE GROWTH ZONE IN A PLANT SHOOT
Zone of cell division/
growth zone
Zone of cell
elongation
Zone of cell
differentiation
M...
THE GROWTH ZONE IN A PLANT ROOT
Root hair
phloem
xylem
Matured tissue
Zone of cell division/
growth zone
Zone of cell
diff...
SECONDARY GROWTH IN
PLANTS
Secondary growth leads to the increase in thickness of a
plant. This is due to lateral meristem...
Structure of Dicot Stem
Lateral meristem – vascular cambium & cork cambium
.Vascular cambium divides to form cambium ring.
.Cambium ring divides t...
Secondary Growth
Xylem
year 1
year 2
year 3
PithVascular
Cambium
Phloem
Cork
Cork Cambium
Note:
Xylem = wood
Cork, Cork ca...
Structure of Dicotyledonous Root
dicotyledonous root
Lateral meristem – vascular cambium & cork cambium
1.Vascular cambium divides to form cambium ring.
2....
THE END
Chapter review…Chapter review…
Growth
Growth phases
Growth curveGrowth curve
sigmoid human Secondary growth
(plants)
insec...
Biology Form 5 Chapter  4 - 4.6 Growth in multicellular organisms
Biology Form 5 Chapter  4 - 4.6 Growth in multicellular organisms
Biology Form 5 Chapter  4 - 4.6 Growth in multicellular organisms
Biology Form 5 Chapter  4 - 4.6 Growth in multicellular organisms
Biology Form 5 Chapter  4 - 4.6 Growth in multicellular organisms
Biology Form 5 Chapter  4 - 4.6 Growth in multicellular organisms
Biology Form 5 Chapter  4 - 4.6 Growth in multicellular organisms
Biology Form 5 Chapter  4 - 4.6 Growth in multicellular organisms
Biology Form 5 Chapter  4 - 4.6 Growth in multicellular organisms
Biology Form 5 Chapter  4 - 4.6 Growth in multicellular organisms
Biology Form 5 Chapter  4 - 4.6 Growth in multicellular organisms
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Biology Form 5 Chapter 4 - 4.6 Growth in multicellular organisms

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Biology Form 5 Chapter 4 - 4.6.Growth in multicellular organisms

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Biology Form 5 Chapter 4 - 4.6 Growth in multicellular organisms

  1. 1. 4.6 GROWTH IN MULTICELLUL AR ORGANISMS
  2. 2. A series of changes in the life of an organism –from zygote to adult – involves two major processes: (i) Growth (ii) Development Growth Phases Introduction
  3. 3. Any irreversible and permanent increase in quantitative parameters that can be measured such as: Growth Phases Definition of Growth size length volume height number of cells dry masscytoplasmic mass surface area
  4. 4. Any qualitative change and involve cell differentiation: Growth Phases Definition of Development shape specificity complexity
  5. 5. Growth Involves 3 processes: • Cell division – mitosis • Cell elongation • Cell differentiation
  6. 6. Growth Phases 1. Cell Division • mitotic cell division in all somatic cells • Through mitosis, the number of cells increase exponentially – 1-2-4-8-16-32
  7. 7. Growth Phases 1. Cell Division Plants – occurs in apical meristem (Root tip/shoot tip) • Cells small, closely arranged, large nucleus • Thin cell wall, no vacuole, dense cytoplasm
  8. 8. Growth Phases 2. Cell Elongation  Plants - cells elongate & expand due to:Plants - cells elongate & expand due to: -- absorption of water, into the cells by osmosis,, into the cells by osmosis, - vacuoles increase in size- vacuoles increase in size - small vacuoles fuse to form a large central vacuole- small vacuoles fuse to form a large central vacuole
  9. 9. Growth Phases 3. Cell Differentiation • the cell undergoes change in shape  in order to perform specialized functions - same set of genetic information to produce a diversity of cell types
  10. 10. • e.g. : meristematic vascular cells • the meristematic cells differentiate into:  xylem: transportation of water and minerals  phloem: transportation of products of photosynthesis and hormones Growth Phases 3. Cell Differentiation
  11. 11. GROWTH OF CELLS CELL DIFFERENTIATION Guard cell and stomata Mesophyll cell phloem xylem Parencymatous cell of cortex
  12. 12. Growth Phases Plants – In Root Tip Three phases / zones: 1. Cell divisions 2. Cell elongation 3. Cell differentiation
  13. 13. THE GROWTH ZONE IN A PLANT SHOOT Zone of cell division/ growth zone Zone of cell elongation Zone of cell differentiation Matured tissue Leaf primordium xylem phloem cambium Apical meristem -produces leaf primordium which protects the meristematic tissue Axial bud -containing cells which are capable to divide to form side branches. 1. Cell divisions 2. Cell elongation 3. Cell differentiation
  14. 14. • Surface area of a leave can be determine by draw the outline of the leave at a graph paper or square paper (1cm x 1cm) and count the square inside the leave outline • What is the surface are for the leave?  20 cm2 / / / / / / / / / / / / / / / / / / / / Measuring Growth Surface Area
  15. 15. the more appropriate parameters for the measurement of growth in multicellular organisms are the weight or mass Measuring Growth • fresh mass/weight • dry mass/weight
  16. 16. • Periodic linear measurementPeriodic linear measurement Eg: Measuring height for human being – the best way to measure the growth of an individual Measuring Growth Estimate length/ height
  17. 17. • the mass of the organism in the normalnormal condition Measuring Growth Fresh Mass The advantages • easier and convenient to measure • no need to destroy the specimen • the same organism can be used for repeated measurement
  18. 18. The disadvantages • inaccurate and inconsistent • because it is affected by the fluctuation of the amount of water in the organism Measuring Growth Fresh Mass ( water ~ 70 - 90% wet mass )
  19. 19. • the mass of the organism after its water content is fully eliminated Measuring Growth Dry Mass: Definition • it implies the actual growthactual growth of the organism
  20. 20. 1. The specimen is destroyed… Measuring Growth Dry Mass: Methods 2. …then transferred into the oven at 110°C to eliminate its water content. 3. Next, it is put inside a desiccator to ensure the water is completely eliminated. 4. The dried specimen is weighed. 5. The above procedures are repeated until a constant value is obtained.
  21. 21. Measuring Growth Dry Mass The advantages • more accurate • the amount of water in an organism is not constant, i.e. depends on the water intake by the individual organism
  22. 22. Measuring Growth Dry Mass The disadvantages • destruction of specimens • in repeated measurement, specimens of the similar age, size are required (destroyed!) to avoid or minimize errors in the measurement • Large samples of genetically identical organism need to be grown under similar condition • Time consuming
  23. 23. If an organism’s measurements (height, weight, etc) are plotted against time, a growth curve is obtained. GROWTH CURVE
  24. 24. Sigmoid Curve Maturity phase Senescence & death
  25. 25. GROWTH STAGES 1. Lag phase: (a)The beginning of the growth process (b)The rate of growth is generally low (c)Cell division by mitosis takes place very actively but there is no increase in cell size. 2. Exponential Growth: a) The highest growth rate b) Increase in the number of cells by mitosis c) Cell size increases by absorbing water and addition of protoplasmic substances.
  26. 26. 3. Maturity Stage a) Growth rate is low b) Cells achieve the optimum size(adult) and there is no more increase in size of the cell. a) A little cell division to replace damaged cells 4. Stationary (Adult) Stage a) Growth rate is zero b) Cells still divide to replace damaged / dead cells 5. Senescence Stage a) Growth rate is negative because of loss of tissues due to aging process
  27. 27. HUMANS GROWTH CURVE VIDEO
  28. 28. GROWTH CURVE OF A HUMAN
  29. 29. GROWTH CURVE OF A HUMAN Time / year Growth ( height/ weight) At birth Rapid growth Slow growth Very rapid growth Very little growth death senescence adult /Adolescence / childhood baby
  30. 30. GROWTH OF A BOY AND A GIRL Rate of increase in height Kadar pertambahan berat Age / years Height/cm boy girl Freshweight Rate of increase in weight boy girl Age / years
  31. 31. GROWTH CURVE OF INSECTS VIDEO
  32. 32. Grasshoppers moult (shed skin) 5 times from 1st instar to adult
  33. 33. Growth curve of insects – staircase shape
  34. 34. PRIMARY & SECONDARY GROWTH IN PLANTS
  35. 35. VIDEO
  36. 36. Growth in Plant
  37. 37. Meristem Actively dividing tissue. • Apical meristem: These are found at the tips of roots and shoots and are responsible for primary growth of the plant. They increase its length. • Lateral meristem: • Cambium & Cork Cambium • They are responsible for secondary growth and cause an increase in girth
  38. 38. Primary & Secondary Growth • All plants exhibit primary growth • Woody plants also undergo secondary growth (increase in girth wood) • Herbaceous plants do not undergo secondary growth
  39. 39. Primary Growth • Primary growth leads to an increase in length of the plant shoots or roots. • It is due to the activity of apical meristems. http://www.ucalgary.ca/~biolcore/biol233/plant5/apicalm agon.seowon.ac.kr/~bioedu/bio/ohp/t-188.jpg Root apical meristem (RAM) Shoot apical meristem (SAM)
  40. 40. THE GROWTH ZONE IN A PLANT SHOOT Zone of cell division/ growth zone Zone of cell elongation Zone of cell differentiation Matured tissue Leaf primordium xylem phloem cambium Apical meristem -produces leaf primordium which protects the meristematic tissue Axial bud -containing cells which are capable to divide to form side branches.
  41. 41. THE GROWTH ZONE IN A PLANT ROOT Root hair phloem xylem Matured tissue Zone of cell division/ growth zone Zone of cell differentiation Zone of cell elongation cortex Apical Meristem Root cap
  42. 42. SECONDARY GROWTH IN PLANTS Secondary growth leads to the increase in thickness of a plant. This is due to lateral meristems. (dicots only) (perennial plants only)
  43. 43. Structure of Dicot Stem
  44. 44. Lateral meristem – vascular cambium & cork cambium .Vascular cambium divides to form cambium ring. .Cambium ring divides tangentially to form secondary xylem inside & secondary hloem outside. .Cork cambium divides to form cork outside. .Lenticels develop to allow gaseous exchange between air & stem .Primary xylem, phloem and pith are “squashed”. Epidermis ruptures.
  45. 45. Secondary Growth Xylem year 1 year 2 year 3 PithVascular Cambium Phloem Cork Cork Cambium Note: Xylem = wood Cork, Cork cambium and Phloem = bark http://www.umanitoba.ca/faculties/science/biological_sciences/lab9/images/til • Each year a new ring of xylem – produces a hard inner core called wood • Spring - fast growth – cells large, thin wall • Autumn - slow growth – cells small , thick walls • Light & dark rings – annual rings – calculate age of tree
  46. 46. Structure of Dicotyledonous Root
  47. 47. dicotyledonous root Lateral meristem – vascular cambium & cork cambium 1.Vascular cambium divides to form cambium ring. 2.Cambium ring divides tangentially to form secondary xylem inside & secondary phloem outside. 3.Cork cambium divides to form cork outside. 4.Primary xylem & phloem compressed.
  48. 48. THE END
  49. 49. Chapter review…Chapter review… Growth Growth phases Growth curveGrowth curve sigmoid human Secondary growth (plants) insects Primary growth (plants) Growth measurement Wet/fresh mass Dry mass Definition Phases of growth Cell division Cell enlargement Cell differentiation

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