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
