Transcript Growth

Growth and Development
Growth
• It is a process involving cell division
and cell enlargement.
• Cell divisions (Mitosis or Meiosis) is
process which leads to an increase in
cell number. Cells are usually small
and unspecialized after cell division.
• Cell enlargement is a kind of process
which leads to an increase in the
volume of individual cells.
Different Ways to Measure
Growth - Dry Mass
• Dry mass : Place in oven at a
temperature slightly over 100oC until
its mass become constant.
• Advantage : Most accurate and
commonly used in plant.
Different Ways to Measure
Growth - Dry Mass II
• Disadvantage : The organism will be
killed. Growth of the same organism
cannot be measured continuously and
large number of organisms are needed.
Finally, time consuming.
Different Ways to Measure
Growth - Fresh Mass
• Fresh Mass : Take the mass of the
organism under normal conditions.
• Advantage : Easy to measure and no
need to kill the organism.
• Disadvantage : Less accurate and
changes in the water content of an
organism are not related to growth.
Different Ways to Measure
Growth - Size
• Size : Measure the organism in different
parameter such as length, height,
surface area and volume.
• Advantage : Easy, quick and no need to
kill the organism.
• Disadvantage : Not accurate enough
because can measure in only one
dimensions and measurement cannot
truly represent its growth.
Development
• Development means the series of
orderly changes that occur in the
body structure and organization (or
qualitative changes) of an organism.
• Starting from the zygotic stage until
maturity.
• Often lead to an increase in the
complexity of the organism.
Process Leading to Development
• Mainly by cell specialization or cell
differentiation.
• Lead to changes in their shapes and
structures of cells, so they can adapt to
certain functions
• Cells will lost their further division ability
after development
Complexity - The Level of
Organization
Organism
System 1
Organ 1
System 2
Organ 2
Organ 3
Organ 4
Tissue A Tissue B Tissue A Tissue C Tissue D Tissue B Tissue C
Cell 1
Cell 2
Cell 1
Cell 3
Cell 4
Cell 2
Cell 3
Complexity - The Level of
Organization II
• Cells  Tissues  Organs  Systems
 Organism
• Cells differentiate into different cell types
and similar cells integrate into tissue which
can perform one or more function(s)
• Combination of different tissues form
organ, which function as a unit.
Complexity - The Level of
Organization III
• Systems are organized by different type of
organs, which carry out a set of functions in
a co-ordinate way to ensure that the
organism works as an integrated whole.
Growth and Development in
Animals
• Cells are grown by repeated mitotic
divisions.
• These processes generate complexity,
which start from zygote to embryo
and then the foetus with tissues
organs and finally, systems developed
before birth.
Growth and Development in
Animals II
• growth curve of human
• five stages
– fast grown in first
three-years of life
and during
adolescence
– the other stages
are relatively slow
growth
Growth and Development in
Animals III
• If the bodies of a man at different ages
are drawn to the same length, and then the
proportion of different body parts is
compared, it can be seen that different
parts of the body grow at different rates.
Growth and Development in
Plants
• Root tip is
the site for
growth and
development
of the root
of plants.
Three Region of Root Tip
• Region of Cell Division:
– contain actively-dividing cells
– new cells are produced continuously by
mitosis.
• Region of Elongation:
– the region of maximum growth in root
– young cells enlarge rapidly here mainly
by an increase in length which involved
cell elongation.
Three Region of Root Tip II
• Region of Differentiation:
– cells undergo cell specialization (or cell
differentiation), i.e. they change their
shapes and structures to become
specialized in different functions.
– As a result, different tissues (e.g. xylem,
phloem, epidermis with root hairs) start
to appear in this region.
Growth Curve in Plant
1) Dry mass decreases during
early stage of germination
because respiration of food
reserves in the seedling
2) Dry mass increases
because leaves are
producing food by
photosynthesis
3) Dry mass decreases due to
deposal of seeds or fruits
Growth and development at the
shoot tip
• Growth in shoots is similar to roots.
There also have 3 regions: region of
cell division, region of elongation and
region of differentiation.