The Non-mammalian

REPRODUCTIVE SYSTEM

III – rubidiumgroup 1

Sexual vs Asexual Reproduction

Asexual reproduction: Gr. “without sex”

Genes come solely from parent

Mitotic cell division

Most suitable for favorable and stable environments

Fission

Budding

Regeneration

and

fragmentation

Sexual vs Asexual ReproductionFISSION

-separation of a parent into 2 or more individuals of approx. equal size, each with a copy of the parent's genetic material

-generally exponential population growth

-ex. bacteria, archaea

FRAGMENTATION: breaking of body into several pieces

REGENERATION: regrowth of lost body parts

Sexual vs Asexual ReproductionBUDDING

-formation of a new organism by the protrusion of part of another organism

-offspring may either detach from parent or remain attached, to eventually form colonies

-ex. cnidarians, tunicates, sponges

*gemmules-formed when different types of cells clump together within the sponge and become surrounded by a protective coat

Sexual vs Asexual Reproduction

Sexual vs Asexual Reproduction

Sexual reproduction: “fusion of haploid gametes to form a diploid zygote”

Requires two organisms

Increases genetic variety through gene shuffling

Used during times of great stress

External and Internal Reproduction

External Reproduction: egg is fertilized in the environment

More zygotes are produced

Situational, but triggered by chemical/behavorial factors (e.g. pheromones)

Internal Reproduction: egg is fertilized in the female reproductive tract

Less zygotes Parental care

increases chances for survival

External and Internal Reproduction

Different Reproductive Strategies

Reproductive cycles

Alternatingly asexual/sexual

Hermaphroditism

Sequential Hermaphroditism

Parthenogenesis

Different Reproductive Strategies

Reproductive cycles

-periodic, only certain times of the year/month

-allows animals to conserve energy when environment is not favorable for reproduction

-related to seasons, hormones-not necessarily for stressful environments

-examples: ewes, humans

Different Reproductive Strategies

Aleternatingly Sexual/Asexual

-asexual when conditions are favorable

-sexual when environment is stressful

-example: aphids, rotifers, Daphnia

Different Reproductive Strategies

Hermaphroditism

- from the the Greek god, Hermes, and the Greek goddess, Aphrodite

- solution to difficulties faced by parasites and sessile animals in sexual reproduction

- each individual has both male and female reproductive organs

-example: tapeworms

Different Reproductive Strategies

Sequential Hermaphroditism

-sex reversal -protogynous: female first-protandrous: male first-associated with size, age, current

environment or population needs -example: wrasses

Different Reproductive Strategies

Different Reproductive Strategies

Parthenogenesis

-fertilization without sex -egg develops without fertilizing-often produces haploid adults-has a role in social organization- example: Cnemidophorus uniparens

Reproductive Systems in Non-mammalians

Gonads – organs that produce gametes

Annelids

Separate sexes but gonads are not distinct

Eggs and sperm develop from undifferentiated cells lining the coelom

When gametes mature, these cells occupy the coelom

Reproductive Systems in Non-mammalians

Arthropods

-males develop sperm in testes, and are conveyed through a coiled duct to two seminal vesicles

-females develop eggs in a pair of ovaries and are conveyed to vagina through ducts

* spermatheca: sac that stores sperm for long periods of time in female reproductive system

Cloaca: common opening of the digestive, excretory, and reproductive system