Chapter 46: animal reproduction Flashcards
what different ways can animals reproduce
asexual and sexual reproduction
what is asexual reproduction and please give some examples
e generation of offspring without the fusion of egg and sperm - budding -fission -parthenogenesis
what is sexual reproduction and what is an example
the generation of offspring by fusion of
haploid gametes, a male sperm and female egg, to form a diploid
zygote
- hermaphroditism
what is budding
simple form of asexual reproduction found among invertebrates
what is fission
separation of a parent into two or more individuals of the same size
what is parthenogeneis
development of a new individual from an unfertilized egg
- mainly observed in invertebrates
what can be challenging for sexually reproducing animals
finding a partner
what is hermaphroditsm
each individual has
both male and female reproductive
systems
- any 2 individuals can mate under this system
what are sexual females
they have half as many daughters compared to asexual females
what is the twofold cost of sexual reproduction
Sexual females have half as many
daughters as asexual females; this is
the “twofold cost” of sexual
reproduction
how can sexual reproduction help in an unfavorable environment
may promote
reproductive success due to genetically
varied offspring
what reproduction is better in a stable favorable environment
asexual reproduction
what controls reproductive cycles
hormones and environmental cues
what do animals relate to reproductive cycles
the season
what is an important cue in reproduction
seasonal temperature
what can decrease reproductive success
climate change
what mechanisms does fertilization depend on
ones that bring together the sperm and egg of the same species
what is fertilization
the union of egg and sperm can be external or internal
what is external fertilization and what are some examples
: eggs shed by the female are
fertilized by sperm in the external environment
- moist habitat (sperm swims to the egg)
- spawning: individuals cluster in the same area to release their gametes into the water
what can triggers spawning
chemical signals
what is internal fertilization
an adaptation that enables sperm to
reach an egg despite a dry external environment
what does internal fertilization require
behavioral interactions
what do mating animals use
pheromones
what are pheromones
chemicals released by one organism that influence the physiology and behavior of individuals of the same species
what do internally fertilized eggs have
shells and internal membranes
what do shells and internal membranes do for the internal eggs
- protect against water loss and physical damage
- some animals retain the embryo which develops inside the female
what is internal fertilization is typically associated with
the production of fewer gametes but the survival of a higher fraction of zygotes
what do you need to do to reproduce asexually
animals must produce gametes from percursor cells
what are gonads
organs that produce gametes
if an organism doesn’t have gonads what do they do
use undifferentiated tissue
what is the elaborate system
: sets of accessory tubes
and glands that carry, nourish, and protect gametes
and developing embryos
what does a female insect have
spermatheca where sperm is stored during copulation
what do most insects have
separate sexes with complex reproductive syste,
what are the male reproductive external organs
scrotum and penis
what are the male internal reprod. organs
gonads, accessory glands, ducts
what are the gonads
produce sperm and hormones
what are the accessory glands
secrete products needed for sperm movement
what do the male ducts do
carry sperm
what is seminiferous tubules
where sperm production happens
how does sperm travel
- ) seminiferous tubules
- ) epididymis
- ) ejaculation through the vas deferens
what is the epidiymis
coiled duct where sperm passes
what is the vas deferens and the ejaculatory duct
- where sperm is pushed through and it exits the urethra
what can’t occur at the body temperatures
the production of normal sperm
flow of sperm
gonads –> seminiferous tubules–> sperm seminiferous tubules (sperm) –> epididymis ejaculation—> vas deferens—> urethra
