SEXUAL REPRODUCTION? Flashcards
SCREEENSHOTTED
Variation in the
offspring
Natural selection
can be speeded up
by humans in
selective breeding
if the environment changes variation gives a survival advantage by natural selection
E.g. if there is a new disease, there may be some offspring with resistance who will survive
increase food
production for
humans
E.g. only allowing
cattle which
produce the most
milk to breed
male gamete?
The male gamete is called a sperm
and are produced in the male gonads
called the testes (singular= testis)
female gamete?
The female gamete is called an ovum
(plural = ova) (more commonly known
as an egg) and are produced in the
female gonads called the ovaries.
function of sperm?
The function of a sperm is to carry the male genetic
information and fertilise the female egg. The nucleus is haploid
(contains half the number of chromosomes as a body cell).
what does the flagellum tail do?
helps the sperm to swim
what does the tip of the head do?
contains enzymes to digest the coat of the egg
what gives the sperm a streamlined shape?
cytoplasm
function of egg?
The function of an egg (ovum) is to carry the female genetic
information and provide nutrients for the embryo following
fertilisation. The nucleus is haploid (contains half the number
of chromosomes as a body cell).
what does the cytoplasm have/do?
contains a store of food for energy
what does the jelly coat do?
it makes sure that only one sperm cell can enter the egg cell
what does the urethra do?
a tube which carries sperm through the penis during ejaculation. urine also passes the urethra to exit the body
what does erectile tissue do?
swells when filled with blood, to make the penis erect
what do the testes do?
where sperm is made
what do the glands do?
produce the liquid thats added to sperm to make semen
what do the vas defernes do?
(sperm duct) musclaur tube that carries sperm from testis towards the urethra
what does the scrotal sac do?
hangs behind the penis and contains the testes
what does the oviduct/fallopian tube do?
a muscular tube that carries the ovum from the ovary to the uterus
what does the uterus/womb do?
the organ where an embryo grows
what does the ovary do?
the organ that produces ova and sex hormones
what does the cervix do?
the neck of the uterus
what does the vagina do?
where the sperm are disposted
sexual reproduction key facts?
- offspring are gentically different to either parent
- offspring inherit features from both parents
- genetic info from 2 organisms is combined to produce offspring
- the gametes fuse together to form a cell with a full number of chromosomes (fertilisation)
- the mother and father produce gametes
- in humans, each gamete contains 23 chromosomes-half the number of chromosomes in a normal cell
why is variation in the offspring a advantage for sexual reproduction?
if the environment changes variation gives a survival
advantage by natural selection
example for variation in the offspring?
E.g. if there is a new disease, there may be some offspring with resistance who will survive
