The Reproductive Process ch 7

Question 1

Asexual Reproduction

Answer 1

 Only one parent; no gametes
 Offspring are genetically identical clones
 Widespread among unicellular organisms
and many invertebrates

Question 2

Four methods of asexual reproduction

Answer 2

Binary fission:
Multiple fission (Schizogeny)
Budding
Fragmentation

Question 3

Binary fission:

Answer 3

is common among bacteria and protozoa or unicellular eukaryotes. In binary fission the body of the unicellular parent divides by mitosis into two approximately equal parts, each of which grows into an individual similar to the parent.

Question 4

Multiple fission (Schizogeny)

Answer 4

the nucleus divides repeatedly before division of the cytoplasm, producing many daughter cells simultaneously. Spore formation, called sporogony, is a form of multiple fission common among some parasitic unicellular eukaryotes, for example, malarial parasites

Question 5

Budding

Answer 5

is an unequal division of an organism. A new individ- ual arises as an outgrowth (bud) from its parent, develops organs like those of the parent, and then detaches itself. Budding occurs in sev- eral animal phyla and is especially prominent in cnidarians

Question 6

Fragmentation

Answer 6

a multicellular animal breaks into two or more parts, with each fragment capable of becoming a complete in- dividual. Many invertebrates, for example, most anemones and many hydroids, can reproduce asexually by simply breaking into two parts and then regenerating the missing parts of the fragments (see Figure 13.12). Many echinoderms can regenerate lost parts, but this is not the same as reproduction by fragmentation.

Question 7

Parthenogenesis

Answer 7

-Embryos develop from unfertilized egg
-Parthenogenesis (“virgin origin”) is the development of an embryo from an unfertilized egg or one in which the male and female nuclei fail to unite following fertilization.

Question 8

What are two types of Parthenogenesis? and what do they do?

Answer 8

• Ameiotic = no meiosis; form diploid eggs via mitosis
• Meiotic = haploid eggs formed; become diploid by duplication of
  chromosomes or rejoin haploid nuclei

Question 9

Advantages and disadvantages of asexual reproduction

Answer 9

Advantages of Asexual Reproduction:
 Pass on 100% of your genes
 No need to find a mate
 Reproduce rapidly
Disadvantages
 Lack genetic diversity to adapt to change
 Accumulate mutations

Question 10

Sexual Reproduction

Answer 10

• Requires 2 parents
• Usually 2 different individuals (Dioecious = separate sexes)
• Haploid gametes fuse
  * Small gametes = male; large gametes = female

Question 11

Hermaphroditism (hermaphrodite)

Answer 11

-Monoecious
-Animals that have both male and female organs in the same individual
-Sequential hermaphrodite
-typically do not self fertilize

Question 12

gonads

Answer 12

Organs that produce germ cells are called gonads. The gonad that produces sperm is a testis (see Figure 7.12) and that which forms eggs is an ovary (see Figure 7.13).

Question 13

Monoecious

Answer 13

have both male and female gonads

Question 14

Sequential hermaphrodite

Answer 14

changes sex (e.g., many fish)

Question 15

Advantages and disadvantages of reproducing sexually

Answer 15

The BIG advantage of sexual
reproduction: beneficial genetic
combinations enable organisms to adapt to changing environments
Disadvantage:
Sexual Reproduction takes time
and energy