The change of shape or characteristics of an organism’s body as it grows and matures.
In some species, diapause occurs when induced by environmental conditions, in some it is part of their life cycle.
Female cockroach lays an egg..when the egg hatches…there is a larvae and it goes through different nymph stages until it becomes an adult.
Frogs undergo a different type of Complete Metamorphosis.From the egg emerges a tadpole, which lives in the water, breathes with gills, and has a tail. As a tadpole grows, lungs and legs form, and the gills and tail are absorbed into the body. Finally, the animal leaves the water and lives mainly on land, as a frog.
The mammalian liver can regenerate if a part is removed. The antlers of a male deer can also regenerateThe emperior newt can also regenerate it’s dorsal crest, retina and lens, jaw and tail.
Gerontology – study of aging and the elderlyPhysical Changes – predictable graying hair, wrinkles, loss of height & weight, decline in strength and vitality and sensory changes. Odds of chronic illnesss and life threatening conditions rise steady
Smiling, Squinting and frowning other facial movements also cause wrinkles
This makes the body susceptible to illness and diseases
Means “change of form” in greek
Metamorphosis refers to the way that certain organisms
develop grow, and change form.
invertebrate animal of the class Insecta of the phylum
. Like other arthropods, an insect has a hard outer covering, or
exoskeleton, a segmented body, and jointed legs. Adult insects
typically have wings and are the only flying invertebrates.
Make up about 75% of the animal world
Their bodies are divided into 3 regions: head, thorax, and
Amphibians – “double life in greek
Environmental factors include temperature, food
levels, tadpole densities, pond evaporation rates &
predator presence such that: increasing temperature,
decreasing food, overcrowding, pond evaporation &
increase in predation all accelerate metamorphosis
Transition from larva to adults involves precisely
controlled gene regulatory events that occur at specific
stages during development
Regeneration is the sequence of morphogenetic events
that restores the normal structure of an organ after its
partial or total amputation.
This has been studied in organisms including hydra,
starfish, zerbafish, newt, mouse, and human.
The human liver is one of the few glands in the body that
has the ability to regenerate from as little at 25% of it’s
Types of Regeneration
1. Physiological Regeneration
There is a constant loss of many kinds of calls due to
wear and tear caused by day-to-day activities. The
replacement of these cells is known as physiological
Replacement of Epidermal Cells on the Skin
Replacement of R.B.C's
Types or Regeneration
2. Reparative Regeneration
This is the replacement of lost parts or repair of damaged
body organs. In this type of regeneration, wound is repaired
or closed by the expansion of the adjoining epidermis over
Regeneration of limbs in salamanders
Regeneration of lost tail in lizard
Healing of wound
Replacement of damaged cells.
Types of Regeneration
In some animals like starfish, some part of the body is
broken off on being threatened by a predator. This
phenomenon of self-mutilation of the body is called
Crabs break off their leg on approaching of the enemy
Holothurians throw off their internal viscera
Starfish breaks off an arm
2Types of Regeneration based on
1. Epimorphosis or epimorphic regeneration :
This type of regeneration involves dedifferentiation of
adult structures in order to form an undifferentiated
mass of cells, or addition of parts to remaining pieces .
For example: limb generation in amphibians
Regeneration in Vertebrates
Early regeneration process of
a deer’s antlers Emperior Newt
2. Morpholaxis or morphollactic regeneration:
In this type, regeneration occurs mainly by the remodelling
of existing tissues and the re-establishment of
boundaries, thus involving very little new growth. As a
result, the regenerated individual is much smaller
initially. It subsequently increases its size and becomes
normal after feeding. This type of regeneration is known
as morphallaxis or morphallactic regeneration.
Example: Hydra, planaria and other invertebrates e.g.
regeneration of the new individual from body pieces.
Regeneration in Invertebrates
A planarian, hydra, and a starfish all show remarkable
powers of regeneration. When parts are removed or a
small fragment isolated. A whole animal can be
Aging is a pattern of life changes that occurs as one
grows older. It is a process that accumulates changes in
organisms or objects over time. Human aging process
involves, psychological, cultural and social levels.
Gerontology – study of aging and the elderly
Physical Changes – predictable graying hair, wrinkles,
loss of height & weight, decline in strength and vitality
and sensory changes. Odds of chronic illness and life
threatening conditions rise steady
A majority of those people over 65 report good health
“well-to-do” people have it better since they can afford
The elderly can become more introspective / more
Major shifts in personalities do not normally take place
Factors that add to the Effects of
1. Ultraviolet light – UV light destroys collagen and
elastic fibers in the skin, without which your skin
starts sagging and wrinkling.
2. Smoking – worsens the process of wrinkling by
affecting the blood supply to the skin and other parts
of the body.
1. Cellular Changes
Cellular multiplication slows down with age. The rate of
T-lymphocytes of the immune system decreases with age.
2. Genetic Factors
The genes associated with the mechanisms of
programmed cells death(apoptosis) also affects aging in
3. Environmental Factors
Environmental stress associated with exposure to
excessive heat and light trigger the activity of aging
genes. Constant exposure to toxins and poisons
accentuate the aging process.
4. Health Conditions
There are certain genetic disorders that completely
change the phenotype of an individual
5. Unhealthy Lifestyle
Aging process in men is mainly brought about by over
consumption of alcohol and heavy smoking. Lack of
exercise, inadequate rest or sleep, mental stress show
symptoms of early aging. Other factors like regular
consumption of excessive spicy food and caffeine
renders and old look. Sloth and sluggish lifestyle
makes one feel old.