B8. Reproduction Flashcards
define asexual reproduction
process resulting in the production of genetically
identical offspring from one parent.
process → identical offspring
define sexual reproduction (full)
process involving the fusion of haploid nuclei to
form a diploid zygote and the production of
genetically dissimilar offspring.
define sexual reproduction (simplified)
fusion of haploid nuclei to form diploid zygote and genetically dissimilar offspring
what is a zygote
fertilized egg
fertilised egg aka…
zygote
what is a gamete
sex cell
what happens at fertilisation
during sexual reproduction the gametes fuse
pros/ cons of sexual reproduction
pros
-produce genetically different offspring
cons
- requires two parents
- take time and energy
- produce fewer offspring
- good characteristic can be lost
pros/ cons of asexual reproduction
- fast: no need to find mate
- good characteristic can be kept
define pollination
the transfer of pollen grains from the male part of the plant to the female part of the plant
anther or stamen → stigma
define pollination
the transfer of pollen grains from the male part of the plant to the female part of the plant
anther or stamen → stigma
describe structure of insect-pollinated flower (full
petal - bright/ scented
nectaries - make nectar(sugary)
stamens:
short filaments
inside flower
carpels:
sticky
inside flower
*for insect to rub against
describe structure of wind-pollinated flower
anther -
loosely attached
outside flower
pollen -
large qualities of smooth, light
carpels -
large, feathery stigma
to catch pollen grains
describe structure of wind-pollinated flower
anther -
loosely attached
outside flower
pollen - large qualities of smooth, light pollen grains
carpels - large, feathery stigma
*can easily be carried by wind
stamen of wind-pollinated flower
long filaments so anthers hang outside flower, loosely attached to filaments, so is blown away easily
short filaments, anthers attached to filaments, inside flower for insect to rub against
stamen of insect-pollinated flower
structure of insect- pollinated flower
stamens:
short filaments
inside flower
carpels:
sticky
inside flower
*for insect to rub against
define germination +*requirement
seeds develops into plants controlled by enzymes
- water - lets seed swell + embryo start to grow
- oxygen - needed for aerobic respiration
- warmth - increases growth rate/ enzyme activities
describe dispersal activities
wind - light, has extension
explosive - pods burst open when ripe projecting seeds away
animal internal - brightly coloured, fruit, indigestible coat
animal external - hook
water - waterproof, hollow,float
Male reproductive system
1.testes :
inside scrotum
male gametes
testerones
- scrotum
aka ball sac
in/out to control temp - sperm duct
connects testies to urethra
4.prostate gland
secretes fluid for swimming
seminal vesicle: sugar
5.urethra
controls so that urine/semen never pass the same time
prevents loss of urine in sex
6.penis
erect in sex
Female reproductive system
Ovaries:
contains follicles
produces/stores egg
oestrogen
Oviducts:
carries ovum to uterus
Fallopian tubes = site of fertilisation
Uterus – where fetus develops
Cervix- ring of muscle, separate vagina from uterus
Vagina: receives sperm from erect penis during intercourse
Comparing male and female gametes
size : small x larger
movement tail lashes side to side x cilia/peristalsis in oviduct
energy store very little - sugar for respiration protein/fat in cytoplasm - enough to last till implantation
number produced milions constantly x 1/month (puberty → menopause)
chromosomes 23(haploid number)
Describe fertilisation
joining of nuclei of male gamete (sperm) and female gamete (egg)
the function of the placenta
Blood from the fetus passes through the umbilical cord in the umbilical artery to the placenta.
Here it comes close to the mother’s blood.
transport O2 + nutrients (amino acids, glucose…) from mother —> fetus
transport CO2 + wastes (urea… ) from fetus —>mother (through umbilical vein).
- transfers O2 from mother to fetus
- transfers nutrients (of named nutrients) from mother to fetus
- transfers CO2 from fetus to mother
- transfers wastes (or named wastes) from fetus to mother
- allows the transfer of antibodies from mother to fetus
- prevents mixing of the blood of mother and fetus.
the function of the Umbilical cord
joins fetus to placenta; contains:
2 arteries: blood from fetus —> placenta
1 vein: returns blood —> fetus
Indicate the functions of the amniotic sac
and amniotic fluid.
Amniotic sac: membrane from embryo cells: encloses fetus, prevents entry of bacteria
Amniotic fluid: supports, protects fetus from mechanical damage; absorbs urine released by fetus.
Describe the function of the placenta and umbilical cord
Umbilical cord
- joins fetus to placenta
- artery: fetus —> placenta, waste
- vein: placenta —> fetus, oxygen n food
- Placenta
Brings blood supply of fetus close to mother’s
-site of gas exchange, nutrients, waste
