BIO 02 Lesson 1: Sexual and Asexual Reproduction

ASEXUAL REPRODUCTION

• Does not require presence of two parents

• single parent produces an offspring

• Commonly found in lower form of organisms

Organism can produce many offspring in a short time without exerting much energy to either produce gametes or to find a mate

ADVANTAGE of ASEXUAL REPRODUCTION

• Lack of variation among individuals

• the changing environment may wipe out a group of these organisms that cannot easily adapt to sudden changes in their environment

DISADVANTAGE of ASEXUAL REPRODUCTION

FISSION

the action of dividing or splitting something into two or more parts.

BINARY FISSION

• Parent cell divides into two

• Ex. Amoeba, bacteria, paramecium, euglena

MULTIPLE FISSION

• Organism divides itself into numerous daughter cells

• Ex. Protozoa and algae (both sexual and asexual)

BUDDING

• an outgrowth (bud) arises from the body

• small part of parent's body grows into new organism

• Ex. Hydra (found on freshwater)

FRAGMENTATION

• Organisms split into fragments

• involves the breaking of the body in small pieces, some which will develop into new adults

• Ex. Planaria, spirogyra, earthworm

• Some animals perform fragmentation followed by REGENERATION

• Ex. Sponges, echinoderms

PARTHENOGENESIS

• the growth and development of embryos occur without fertilization.

• Parthenogenesis in animals means development of an embryo from an unfertilized egg cell

• Ex. Some insects (BEES), some reptiles, some fish, flatworms, crustaceans

• Also occurs in plant

FISSION

BUDDING

FRAGMENTATION

PARTHENOGENESIS

TYPES OF ASEXUAL REPRODUCTION

GAMETOGENESIS

SPAWNING/MATING

FERTILIZATION

TYPES OF SEXUAL REPRODUCTION

SEXUAL REPRODUCTION

• Involves fusion of two sex cells to form a zygote

• requires two parents

• offspring shows variations and are not the exact copy of the parents

GAMETOGENESIS

• "Creation of gametes"

• Testes (produce male gametes)

• Ovaries (produce female gametes)

HERMAPHRODITE

an organism that has both male and female reproductive organs

SEQUENTIAL HERMAPHRODITISM OR SEX REVERSAL

Among many fish species as well as some lizards, individuals can change their sex in response to social or environmental change.

PROTOGYNY

a change from female to male

PROTANDRY

a change from male to female

FERTILIZATION

• "primary goal of sexual reproduction"

• meeting or merging of sperm and egg cells to produce an offspring

EXTERNAL FERTILIZATION

The process by which the female lays eggs and the male fertilizes them once they are outside of the female

INTERNAL FERTILIZATION

The process by which the male places sperm inside the female's body, where the eggs are fertilized

SPAWNING/MATING

- "Bringing gametes together"

- Spawning (external fertilization)

- Mating (copulation)

Oviparous

- Animals that LAY EGGS

Viviparous

- Animals that DON'T LAY EGGS but rather give BIRTH

Ovoviviparous

- Animals that retain their eggs in the body in some ways.

- Ex. Garter snakes retain their eggs inside their abdomen until they are ready to hatch

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