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  1. 1. Metamorphosis  Means “change of form” in greek  Metamorphosis refers to the way that certain organisms develop grow, and change form.
  2. 2. 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
  3. 3. Parts of an insect (bee)
  4. 4. Diapause  This is the suspension of development that can occur at the embryonic, larval, pupal, or adult stage, depending on the species
  5. 5. 2 forms of development 1. Incomplete - it has three stages - egg --> nymph --> adult - at each stage, the insects looks much the same as it becomes an adult
  6. 6. 2 Forms of Development 2. Complete - there are 4 stages of development - egg --> larvae --> pupae --> adult
  7. 7. Life Cycle of a Butterfly
  8. 8. Life Cycle of a Frog
  9. 9. 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
  10. 10. 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.  iv/growth-regeneration-ageing/regeneration.php
  11. 11. 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
  12. 12. 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.
  13. 13. 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
  14. 14. 2Types of Regeneration based on Cellular Mechanism 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
  15. 15. Regeneration in Vertebrates Early regeneration process of a deer’s antlers Emperior Newt
  16. 16. 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.
  17. 17. 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.
  18. 18. 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.
  19. 19. Normal Effects of Aging in the Body
  20. 20. 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
  21. 21. Psychological Changes  The elderly can become more introspective / more “self-awareness”  Major shifts in personalities do not normally take place
  22. 22. Factors that add to the Effects of Aging 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.
  23. 23. Aging Process 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 individuals. 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.
  24. 24. 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.