reproduction Flashcards
asexual reproduction
process resulting in genetically identical offspring from one parent
advantages and disadvantages of asexual reproduction
Advantages:
- Saves time and energy (only one parent needed)
- Quick reproduction
- Farming - crops can be reproduced very easily AND offspring will have the same desirable characteristics as parents (eg. A specific fruit)
Disadvantages:
- Evolution NOT possible - makes species more vulnerable to environmental changes (eg. Diseases)
sexual reproduction
- Process involving the fusion of the nuclei of two specialized sex cells to form genetically different offspring
fertilization def.
the fusion of the nucleus of the male gamete (sperm cell) with the nucleus of the female gamete (egg cell/ovum) to produce a zygote.
haploid meaning
nucleus of a gamete
single set of unpaired chromosomes
diploid meaning
nucleus of a zygote
two sets of chromosomes (one from each parent)
advantages and disadvantages of sexual reproduction
Advantages:
- Evolution/variation possible
- Selective breeding - farmers producing crops can choose the best characteristics from two different strains to produce new varieties of plant
Disadvantages:
- Takes time and energy
pollination meaning
the transfer of pollen grains from the anther to the stigma
male part in a flower
stamen
consists of an anther and filament
female part in a flower
carpel
consists of a style, ovary and stigma
sepal function
to protect the growing flower and help to stop it drying out
petal function
to attract insects, birds or mammals to carry out pollination
stamen function
to produce male gamete (pollen) and provide the correct structures and conditions necessary for the transfer of pollen
filament function
to hold the anther in a position where it is able to transfer pollen to an insect, mammal or bird
anther function
to produce pollen which contains the male gamete
stigma function
to trap pollen from other flowers
style function
to support and present the stigma in a position where it can receive pollen from an insect, bird or mammal
carpel function
to produce female gametes and provide the right structures and conditions necessary for fertilization
ovary function
contains ovules (which contains the female gamete) which will develop into seeds after fertilization
ovule function
female gametes are produced and contained within the ovules.
self-pollination meaning
- The transfer of pollen from the anther of a flower to the stigma of the same flower or a different flower on the same plant
self-pollination advantages and disadvantages
Advantage: no need to rely on pollinators, flowers may grow in areas where pollinators may not live
Disadvantage: no variation
cross-pollination meaning
The transfer of pollen from the anther of one flower to the stigma of another flower on a different plant of the same species
cross-pollination advantages and disadvantages
Advantage: yes variation
Disadvantage: relies on pollinators
petal in wind-pollinated flower
small and usually dull in color
petal in insect-pollinated flower
large and brightly colored
anther in wind-pollinated flower
loosely attached and dangle outside the flower
anther in insect-pollinated flower
located inside flower
stigma in wind-pollinated flower
feathery, loosely attached and dangle outside flower
stigma in insect-pollinated flower
located inside flower
germination definition
process in which seeds grow and develop to become a plant
conditions for germination
- Water
- Oxygen
- Weather
testis function
organ in which sperm cells and testosterone are produced
scrotum function
sack of skin that contains the testes, helping to keep them at a slightly lower temperature than the rest of the body
prostate glands function
secretes fluid that nourishes and protects the sperm
sperm duct function
muscular tube that connects a testis to the urethra
urethra function
tube that allows the passage of semen and urine through the centre of the penis
penis function
during sexual intercourse, the penis is inserted into the vagina, allowing the sperm to transfer into the female reproductive system
the sperm cell consists of:
the flagellum
mitochondria
acrosome
nucleus
ovary function
produces:
- egg cells
- oestrogen
- progesterone
oviduct function
tube connecting an ovary to the uterus; where fertilization occurs
uterus function
organ in which the embryo develops
cervix function
ring of muscle between the vagina and the uterus
vagina function
elastic muscular canal through which the newborn passes during childbirth
during sexual intercourse, male’s penis is inserted into vagina
Embryo definition
a ball of cells produced by cell division of a zygote
amniotic sac
thin sac that protects the fetus within the uterus. Filled with amniotic fluid
placenta
structure that grows inside the mother, attached to the wall of her uterus
functions of the placenta
- Transfers substances from the mother to the fetus
- Transfers waste substances from the fetus to the mother so she can excrete them
umbilical cord
connects the fetus to the placenta
main male sex hormone
testosterone
main female sex hormone
oestrogen
what are the 4 hormones involved in the control of the menstrual cycle and pregnancy
- FSH
- LSH
- Oestrogen - produced by the ovary
- Progesterone - produced by the corpus luteum in the ovary
FSH effect
causes an egg in the ovary to mature
LH effect
stimulates the release of a mature egg
oestrogen and progesterone effect
involved in maintaining the lining of the uterus
FSH interaction
stimulates the ovary to secrete oestrogen
oestrogen interaction
inhibits the release of FSH
stimulates the release of LH
progesterone interaction
inhibits the release of FSH and LH
around 8-12 weeks of pregnancy, what happens?
the placenta takes over the production of oestrogen and progesterone, ensuring that:
- No more eggs are released from the ovaries
- Maintain a thick uterus lining to support the growing fetus
- Prevent the muscles of the uterus contracting, which would cause the early delivery of a premature baby
