Plant and Human Reproduction Flashcards
Asexual Reproduction
- Genetically Identical offsrping
- No gametes produced
- No fertilisation
- Stable enviroment
Sexual Reproduction
- Genetic variation in offsprint
- Gametes produced
- Fertilisation
- Changing enviroment
Haploid
One set of chromosomes
Diploid
Two sets of chromosomes
Fertilisation
Fusion of male and female gamete to form a zygote
Zygote undergoes cell division to develop to an embryo
Wind Pollination
- Stamen is exposed - pollen can blow away
- Stigma is exposed - catch pollen
- Small
- Dull petals
- No nectar
- Pollen grains are smaller and smoother - travel further in wind
Insect Pollination
- Stamen is enclosed - insect has to come in contact
- Stigma is enclosed
- Brightly coloured petals
- Big
- Nectar - sweet liquid containing sugars
- Pollen grains are large and sticky
Seed and Fruit formation
- Male gamete fuses with female gamete (fertilisation)
- Zygote forms
- Zygote develops into an embryonic plant (with a small root and shoot)
- The rest of the ovule develops into a food store
- Ovule wall becomes the seed coat (testa)
- Ovary wall becomes the fruit wall (pericarp)
Shoot
Plumule
Root
Radicle
Germination of seed
- during germination food store is used up for growth
- Radicle grows downwards into soil to absorb waer and mineral ions
- Plumule grows upwards towards ligh for photosynthesis
Asexual Reproduction of plants by natural methods
Runners - Part of plant grows off were it touches the ground a new plant is formed
Plants asexually reproduce by artificial methods
Cuttings
- Branch from parent cell is cut off wiht a few leaves
- Stem is placed in damp compost with plant hormones
- promotes growth of new roots to develop
Placenta
Connects/Anchors the baby to the Uterus
Role of the placenta
- transfers nutrients between mother and embryo
- embryo removes waste products - urea and CO2
- mother provides glucose, oxygen, glycerol and fatty acids, amino acids
Amniotic fluid
protects the embryo from sudden movements and bumps
in the amniotic sac which acts as a cushion
Female sexondary sexual characteristics
- Menstrual cycle begins
- growth of sexual organs
- Breasts develop
- pubic and underarm hair
Male sexondary sexual characteristics
- sperm production starts
- growht of sexual organs
- growth of hair
- growth of muscles
- voice breaks
Male Reproductive systems
Testes - produce sperm and testosterone
Sperm Ducts - carry sperm from testes to urethra
Urethra - Carry sperm and urine out of body
Female reproductive system
Ovaries - contain egg cells, release one per cycle
Fallopian Tube - transfers egg to uterus
Uterus - muscular wall were embryo devlopes
Cervix - prevents bacteria entering widens during birth
