(FLASHCARDS) Lesson 18: Animal Reproduction

Haploid

Meiosis is the formation of __________ gametes

Fertilization

Fusion of gametes to form a diploid zygote

genetic diversity

Meiosis and fertilization results in genetically unique offspring → promotes ____________.

One

Asexual reproduction involves _______ parent(s).

mitosis

Asexual reproduction utilizes __________ offspring are genetically identical to the parent.

Parthenogenesis

Ex of Asexual reproduction: Females produce offspring from unfertilized eggs (seen in honeybees, Komodo dragons, salamanders, lizards).

hermaphrodites

Have both testes and ovaries; earthworms (require mate) and tapeworms (self-fertilize)

Protogyny

Female → male (e.g., bluehead wrasse).

Protandry

Male turns into female

temperature

Sex determination is ______________ based in fish and some reptiles.

genetic

Sex determination is _________ in mammals.

External

____________ fertilization: Common in fish/amphibians; gametes released into water.

Internal

_____________fertilization: Common in terrestrial animals.

Oviparity

When eggs laid outside (e.g., monotremes).

Ovoviviparity

When eggs hatch inside the body

Viviparity

When young develop inside mother, nourished by the mother (placental animals)

Testes

Produce sperm and testosterone; located in scrotum for optimal temperature.

Seminiferous tubules

Site of spermatogenesis.

Epididymis

Sperm maturation and storage

Vas deferens

Carries sperm to urethra

urethra

Passage for semen through the penis

Seminal vesicles, prostate gland, and bulbourethral glands

Three glands which add to the semen

primary spermatocytes

Germ cells → ______________ → meiosis → spermatids → mature sperm.

Sertoli

_______ cells help sperm develop.

Leydig

___________ cells (between tubules) produce testosterone.

anterior pituitary

Hypothalamus releases GnRH → stimulates ______________.

FSH and LH

Anterior pituitary releases:

LH

____ → targets Leydig cells → produce testosterone.

FSH

_____→ targets Sertoli cells → support sperm production.

negative feedback

Testosterone and inhibin provide _________________ to regulate LH and FSH levels.

Ovaries

Produce eggs and hormones (estrogen, progesterone).

Fallopian tubes

Transport secondary oocyte; site of fertilization

Uterus

Muscular organ where embryo/fetus develops

Cervix

Narrow opening between uterus and vagina

Vagina

receives sperm, also the birthing canal

if fertilization occurs

Meiosis II completes only _________________.

meiosis I

Oogenesis:

Begins before birth: germ cells enter ___________ and pause in prophase I.

puberty

At ___________, some follicles resume development.

secondary oocyte + polar body

One dominant follicle completes meiosis I each cycle → forms ___________+___________.

GnRH

Hypothalamus → ______ → pituitary → LH and FSH.

follicle development in ovary

FSH and LH stimulate…

LH

___ surge triggers ovulation.

Corpus luteum

___________ forms post-ovulation → secretes estrogen and progesterone.

degenerates

If no fertilization → corpus luteum _______________ → hormone levels drop → menstruation.

hCG

If fertilization occurs, embryo produces ______ to maintain corpus luteum and prevent menstruation.

Follicular

___________ phase: Follicles mature; rising estrogen.

Luteal phase

__________ phase: Corpus luteum secretes progesterone and estrogen

Menstrual

__________ phase: Shedding of endometrial lining.

Secretory

____________ phase: Progesterone (and estrogen) prepare linin for implantation

Proliferative

_____________ phase: estrogen stimulates regrowth of lining

no pregnancy

If ____________, hormone levels drop → cycle restarts.

pregnancy occurs

If _______________, hCG keeps corpus luteum active → no menstruation.