Animal Reproduction I

What is sex?

mechanism by which genes of 2 individuals are combined to produce offspring

What is sexual reproduction?

Each parent produces specialized reproductive cells

What are gametes?

Reproductive cells, product of meiosis haploid

• primary sex/reproductive organ

What are examples of asexual reproduction?

Budding

• mitotic outgrowth of parent

Fission

• splitting into 2+ individuals

  • can retain favorable combos of genes

  • relatively rapid

  • con: genetic diversity - adaptations

What is parthenogenesis?

Development of offspring from unfertilized egg

• usually haploid

• most species that reproduce this way also sometimes use sexual production/behavior

• hormonal control of sex role

What is regeneration?

Complete organism can be made from small fragments of the animals body

What are the pros/cons of sexual reproduction?

Most animals are capable of sexual reproduction

Cons:

• finding mates

• competition

• successful mating

• breaks up favorable gene combos

Pros:

• Greater genetic diversity

• Capability to adapt to changing environment

• removal of deleterious mutations

What is gametogenesis?

Process that produces gametes

• spermatogenesis

• oogenesis

What is germ cells?

Diploid cellos that can use meiosis to make gametes

What are polar bodies?

Small cells produced by unequal division of cytoplasm in cell division

• female meiosis

What are examples of somatic cells that assist in reproduction?

• Sertoli cells - assist sperm production

• Interstitial cells - secrete testosterone

• Germ cells - produce sperm

What is the structure of spermaqtozoon?

Head

• Nucleus

• Acrosome

  • lysosome, enzymes to penetrate egg

• Basal body of flagellum

Tail

• Midpiece

  • thick, many mitochondria to make ATP

  • Principal piece

  • End piece

What are the somatic cells in the ovaries?

Ovarian follicle

• develops ovum and support cells

Ovulation

• release of an ovum from ovary

What is fertilization?

Fusion of ovum and sperm

What is external fertilization?

When fertilization happens outside of the body of a female in water

• spawning - most aquatic animals release gametes into water

What is internal fertilization?

When the male inserts sperm into reproductive tract of female

• moisture, protective egg shell, protection, nutrients

What is a polyspermy?

When more than one sperm fertilizes an egg

• →abnormal polyploidy

What are the two ways to block polyspermy?

1. Fast block

   • rapid depolarization across membrane

2. Slow block

   • Ca2+ release, cortical granules release contents, fertilization envelope is formed

What is the sperm pathway?

1. testes

2. epidiymis

3. vas deferens

4. ejaculatory duct

5. urethra

What parts of the male sex organs?

Seminal vesicles - fluid and energy sources

Prostate gland - alkaline buffer, sperm activation

Bulbourethral gland - musce/lube

What are the two types of ovulation?

1. Spontaneous

   • controlled by hormones

   • timed cycles

   • large element of chance

2. Induced

   • triggered by sex

   • neurons send signals to hypothalamus

   • GnRH release → FSH and LH

What happens during pregnancy?

Blastocyst forms, burrows into uterine wall, releases CG hormone

• Corpus luteum maintained, secreting progesterone to maintain early stage of pregnancy

Placenta develops

• gas exchange

• blood does not mix