The document discusses two biological processes: parthenogenesis and autotomy. Parthenogenesis is the development of an unfertilized egg into an adult organism, which normally occurs after fertilization but can sometimes be induced spontaneously. Autotomy is the self-induced detachment of a body part, such as the tail in some lizards and salamanders, as a defense mechanism. Both processes involve specific changes or events occurring at the cellular or tissue level.

2. GROUP 3

3. The development of an unfertilized egg into an adult
organism. Activation of development normally occurs after an
egg is fertilized by a sperm; in parthenogenesis, however, the
stimulus for the egg to cleave occurs spontaneously or can be
induced experimentally. The mechanism or events occurring
during egg activation are not known but apparently include
certain changes in the egg membrane

4. • . In a female, an egg undergoing the first
meiotic division produces two cells, both of
which contain a diploid number of
chromosomes. One of these cells atrophies; in
this state it is known as the first polar body
and remains attached to the other cell.
Parthenogenic activation occurs at this stage
of development.

6. The self-induced releasing of a specific body part. In certain
lizards, it is the tail that autotomizes; in plethodontid salamanders
(terrestrial salamanders lacking gills and lungs in the adult form), it
is their tails, digits, and portions of their limbs.

7. • Lizards do not autotomize their digits or
limbs. If your lizard's toes have are falling
off, this is a serious medical problem that
requires veterinary attention now. In a
few lizards, it is pieces of skin that
autotomize, a defense strategy known as
"fragile skin."