Animal reproductionI exam 3 diversity

sex

Gametes

reproductive cells, products of meiosis, haploid

• primary sex/reproductibe organ

• egg - sperm

budding

• asexual

• mitotic outgrowth of parent

Fission

• asexual

• splitting into 2+ peeps

coral can reproduce

with…. budding fission and sex

can to asexual reprduction

not a lot of genetic diversity of adaptions

pros of asexual reproduction

• rapid

• can retain favorable combinations of genes

parthenogensis

• asexual reproduction

• development of offspring from unfertilized egg

  • usually haploid - adult diploid

    • most likely gene duplication early on in development

• most species that reproduce this way also sometimes use sexual reproduction or sexual behavior

• hormonal control of sex role

  • a flux in progesterone - male behavior or esstergen - female behavior

Regeneration

• asexual

• complete organism can be made drom small fragments of animal’s body

  • sponges echinoderms worms

some Asxeual reproduction needs …… behavior

sexual

most animals are capable of ——- reproduction

sexual.

disadvantages of sexual reproduction

• finding mates

• competition

• seccessful mating

• breaks up favorable gene combinations

advantages to sexual reproduction

• greater genetic diversity

• capability to adapt to changing environment

• remoal of deleterious mutatios

gametogenesis

• process that produces gametes

  • spermatogensis

  • oogensis

Germ cells

• diploid cells that can use meiosis to make gametes

Polar bodies

• small cells produced by unequal division of cytoplasm in cell division- female meiosis.

more than 1 type of cell in gonads

somatic cells

germ cells

somatic cells

• contribute to reproduction as well, secrete hormones, metabolic support

  • sertoli cells

  • interstital cells (leydig cells)

Sertoli cells

assist sperm production

interstitial cells (leydig cells)

secrete testerone

germ cells

produce sperm.

spermatozoon

• head

  • nucleus

  • acrosome

    • lysosome

    • enzymes to penetrate egg

  • basal body of flagellum

• tail

  • midpiece

    • thick, many mitochondira to make ATP

  • Principal piece

  • end piece

somatic cells in ovaries

ovarian follicle

ovulation

ovarian follicle

• developing ovum & support cells

Ovulation

• release of ovum from ovary

• spontaneous or induced

External feritlization

• when fertilization happens outside the body of female in water

  • spawning - most squatic animals release gametes into water

Internal fertilization

• male inserts sperm into reproductive tract of femals

  • moisture, protective egg shell, protection nutrients.

Fertilization

• is the fusion of ovum and sperm

• recognition molecules must match

• 1 - acrosomal process formed

• 2 - release of digesting enzymes

• 3-nucleus of sperm enters ovum

• 4- sperm organelles degraded.

fertilization challeneges

• sperm and egg of same species need to be brought together

  • behavior processes

  • estrus/heat - time when ova released from ovaries

  • chemical attractants

• polyspermy

  • 2+ sperm fertilize egg → abnormal polyploidy

blocks to polyspermy

• fast block

  • - rapid depolarization across membrane

• slow block

  • Ca2+ release

  • cortical granules release contents

  • fertilization envelope formed.

sex determination

• fertilization - placental mammals, drosophilia

• environmental sex determination

  • e.g. turtlles & temp

  • e.g. alligators (colder-male, warmer -female )

• Hermaphrodiyes

  • sex xhange as adults

  • produce sperm and ove

  • some seq

  • reef fishes - breeding male and female

male sex organs

• produce and deliver semen

sperm pathway

1- testes

2- spidiymis

3- vas deferens

4-ejaculatory duct (higher in prostate glad)

5- urethra (lower in prostate gland)

semen

• sperm+fluid produced by accessory glands

  • seminal vesicles

  • prostate gland

  • bulbourethral gland

seminal vesicles

• fluid & E sources

Prostate gland

• alkaline buffer, sperm activation

bulbourethral gland

• mucus/ lubricant

spontaneous ovulation

• ovulation controlled by hormones

• timed cycles - ovarian cycle

• large element of chance

Induced ovulation

• triggered by copulation

• e.g. rabbit, camelids

• neurons send signal to hypothalamus

  • GnRH release → FSH & LH

Female cycles

• ovarian cycle

• uterie/mentstrul cycle

• distinct, but occur simultaneously

Ovarian cycle

• directed by hormones, cyclical

• repeat unless pregnancy occuts