Chapter 46 Animal Reproduction Flashcards
how do prokaryotes reproduce? eukaryotes?
- asexual
- asexual and sexual
two types of asexual reproduction?
fission- separate into two, about the same size (invertebrates)
budding- happens in yeast and hydra
complete organism formed from a fragment of the parent body. seen in starfish, planarian, and cnidarians
fragmentation/regeneration
development of offspring from unfertilized eggs
parthenogenesis
some animals reproduce sexually or parthenogenetically
How do most eukaryotic species reproduce?
sexually
- related to changing seasons
- controlled by hormones
- seasonal temperature
reproductive cycles
what is unique about whiptail lizards?
-asexual but still have male and female mating behaviors based on hormone fluctuations
- have both male and female reproductive systems
- in some species, organisms can fertilize their own eggs
- most exchange sperm with another individual to increase genetic diversity
- some have sex reversal
hermaphroditism
- eggs and sperm are released in close proximity
- occurs in aquatic environments
- species-specific behaviors to bring egg and sperm together
- usually release very large numbers of eggs at once (spawning- when they release their gametes at the same time)
external fertilization
internal fertilization is typically associated with production of _______ gametes but the survival of a ________ fraction of zygotes.
parental care of young.
fewer, higher
germ cells multiple by mitosis resulting in __________ or _________. They then multiply again by mitosis to produce primary ________ and ________.
spermatogonia (2n) or oogonia (2n)
spermatocytes, oocytes
may undergo processes of meiosis to form gametes
enzyme in sperm head to help sperm penetrate the egg
acrosome
spermatogonia –>
primary spermatocytes undergo meiosis I to produce…
then undergoes meiosis II to produce…
2 haploid secondary spermatocytes
4 haploid spermatids, eventually mature to become sperm
spermatogonia is… (haploid or diploid?)
diploid, haploid after meiosis I
in spermatogenesis, one cell eventually becomes…
in oogenesis…
4 gametes
1 gamete for each primary oocyte
what are the two layers around the ova?
zona pellucida and cumulus mass
in mammals, oogenesis begins in the…
female fetus before birth
primary oocytes begin meiosis but get arrested in….
prophase I,
every monthly cycle completes meiosis 1
in oogenesis, each meiotic division results in 1 large cell (________ in meosis I and ______ in meiosis II) and 1 small cell (polar body)
secondary oocyte, ovum
spermatogenesis differs from oogenesis in what three ways?
- all four products of meiosis develop into sperm while only one of the four becomes an egg
- occurs throughout adolescences and adulthood
- sperm are produced continuously without the prolonged interruptions in oogenesis
in fertilization, sperm contact plasma membrane of ova using _______ enzymes in acrosome to digest the _________.
proteolytic, zona pellucida
scrotum holds testes where sperm can develop at ___ degrees C lower than the core body temperature
2
when the sperm fertilizes the egg, only the _______ enters.
nucleus
sperm is manufactured in the ________ within the testicles
seminiferous tubules
site of spermatogenesis? what cells do they contain?
seminiferous tubules, leydig cells to secrete testosterone and sertoli cells that provide nutrients and protection to the developing sperm
where does sperm become fully mature?
what leads to ejaculatory duct and urethra?
in the epididymis
vas deferns
sperm is about ____% of the semen volume
5
what is the fluid of semen composed of?
- fluid from seminal vesicles that produce 60% of the semen volume
- fluid from the bulbourethral glands (small gland beneath the prostate) produce alkaline fluid
- fluid from the prostate gland, anticoagulant and citrate, to enhance the motility of the sperm
- regulates process in gonads
- production of sex hormones
LH and FSH
what are the sex hormones responsible for?
- gamete production
- sexual behavior
- primary and secondary sex characteristics
-stimulates Leydig cells to produce testosterone
LH
-acts on Sertoli cells and germ cells to stimulate spermatogenesis
testosterone
controlled by negative feedback
stimulates Sertoli cells and spermatogenesis
FSH and testosterone
what gets released when the follicle breaks open?
secondary oocyte
______ convey the egg to the uterus
_______ draws the egg into the oviduct
cilia
fimbriae
females are born with all the ________ they will ever have
primary oocytes
primary oocytes are present at birth, they are arrested in ____________
each month the primary oocyte will be completing ________
secondary oocyte arrested at ________
prophase of meiosis I
meiosis I
metaphase of meiosis II, if sperm penetrates then meiosis II will resume
blastocyte is a ball of ______ cells that enters the uterus
32-150
_________ have a negative feedback effect on the hypothalamus and pituitary in the luteal phase
progesterone and estrogen
in the ovarian cycle, the hypothalamus is inhibited by… and stimulated by…
combination of estradiol and progesterone
in the ovarian cycle, the pituitary is inhibited by…
low levels of estradiol
small amounts of ______ stimulate the follicle to grow
LH and FSH
when estradiol increases, _______ increasses
LH and FSH
the uterine phase where the endometrium thickens that coordinates with the follicular phase
proliferative phase
the uterine phase that includes the secretion of nutrients and coordinates with the luteal phase
secretory
