Metamorphosis Means “change of form” in greek

Metamorphosis refers to the way that certain organisms

develop grow, and change form.

Insects

invertebrate animal of the class Insecta of the phylum Arthropoda

. 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 abdomen

Parts of an insect (bee)

Diapause This is the suspension of development that can occur

at the embryonic, larval, pupal, or adult stage, depending on the species

2 forms of development1. Incomplete

- it has three stages

- egg --> nymph --> adult

- at each stage, the insects looks much the same as it

becomes an adult

2 Forms of Development2. Complete

- there are 4 stages of development

- egg --> larvae --> pupae --> adult

Life Cycle of a Butterfly

Life Cycle of a Frog

Environmental Influences 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 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 tissue.

http://www.tutorvista.com/content/biology/biology-iv/growth-regeneration-ageing/regeneration.php

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 regeneration

Example: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 the wound.

Example:

Regeneration of limbs in salamanders

Regeneration of lost tail in lizard

Healing of wound

Replacement of damaged cells.

Types of Regeneration 3. Autonomy

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 autotomy

Example:

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 Cellular Mechanism1. 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 VertebratesEarly 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 regenerated.

Aging 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.

Normal Effects of Aging in the Body

Biological changes 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 preventive care

Psychological Changes The elderly can become more introspective / more

“self-awareness”

Major shifts in personalities do not normally take place

Factors that add to the Effects of Aging1. 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.

Aging Process1. Cellular Changes

Cellular multiplication slows down with age. The rate of T-lymphocytes of the immune system decreases with age.

2. Genetic FactorsThe genes associated with the mechanisms of programmed cells death(apoptosis) also affects aging in individuals.

3. Environmental FactorsEnvironmental 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.