Reproduction Flashcards
Asexual reproduction
1 parent
No gametes
No fertilisation
Results in genetically identical cells
Sexual reproduction
2 parents
Gametes
Fertilisation
Results in genetically different cells
Advantage of of sexual reproduction
Likely to survive a changing environment
Advantage of asexual reproduction
Can clone rare species
What is pollination
Pollen grains transferred from the anthers to the stigma
What is self pollination
Occurs on the same flower
What is cross pollination
Transferred to a different flower ( by wind or insect )
Features of insect pollinated plant
Bright large and colourful petals
Scented and has nectar
Small round sticky stigmas enclosed in flower
Features of wind pollinated plant
Small dull petals
Not scented and no nectar
Large feathery stigmas exposed outside flower
Small and light pollen
Male gamete in a plant and where it’s produced
Pollen
Anther
Female gamete in a plant and where it’s produced
Ovum
Ovary
Describe steps of fertilization
Pollen grains land on stigma
Pollen grain grows a pollen tube down style into ovary
Pollen nucleus travels down pollen tube and moves into the ovule
Pollen nucleus fertilisés the ovum nucleus
Describe steps of fertilization
Pollen grains land on stigma
Pollen grain grows a pollen tube down style into ovary
Pollen nucleus travels down pollen tube and moves into the ovule
Pollen nucleus fertilisés the ovum nucleus
4 different ways seeds can be dispersed
Wind
Water
Animals (carrying or consuming)
Mechanical (bursting or shaking)
4 different ways seeds can be dispersed
Wind
Water
Animals (carrying or consuming)
Mechanical (bursting or shaking)
What 3 conditions are needed for germination to occur and why
Water - starch digestion (hydrolysis)
Oxygen - respiration to release energy from stored food
Warmth - enzymes that digest starch and carry out respiration are active
Adaptations of sperm
Haploid nucleus (half genetic info)
Many mitochondria (respiration) for energy
Head contains enzymes to break into egg membrane
Long tail to swim to egg
Adaptations of sperm
Haploid nucleus (half genetic info)
Many mitochondria (respiration) for energy
Head contains enzymes to break into egg membrane
Long tail to swim to egg
Adaptations of egg cells
Haploid nucleus
Outer membrane only letting 1 sperm enter
Nutrient rich cytoplasm
What is fertilisation and where does it happen
Fusing of sperm and egg nucleus to form a zygote
Happens in oviduct
(Zygote to embryo to foetus to baby)
What is fertilisation and where does it happen
Fusing of sperm and egg nucleus to form a zygote
Happens in oviduct
(Zygote to embryo to foetus to baby)
What is implantation
Embryo embeds itself into lining of the uterus
Allows placenta to fomr
Why do we need to go through puberty
To adapt to allow reproduction to take place
2 changes that only occur in males during puberty
Tested produce sperm
Hair grows on face and chest
2 changes that only occur to females during puberty
Menstrual cycle starts
Breasts develop
What happens to the level of progesterone if a women is pregnant
High levels
Prevents shedding of uterus
4 main events of menstrual cycle
Prepare an egg
Repair and thicken lining of uterus
Ovulation - release a mature egg
Maintain the uterus lining
What is the role of the placenta
Allows substances to diffuse
Provides foetus with oxygen and nutrients
What is the role of the umbilical cord
Connects the foetus to the placenta
What is the role of the amniotic sac
Shock absorber
Cushions and protects foetus
How is placenta specialized for exchange
Villi - increase SA for diffusion
Maintains good blood supply - provides a conc gradient
Short diffusion distance
