Reproduction and inheritance

Sexual Reproduction is the fusion of male and female gametes. A mix of genes.

Asexual Reproduction involves only one parent. Offspring have Identical genes.

Fertilisation involves the fusion of a male and female gamete to produce a zygote that undergoes cell division and develops into an embryo.

Insect Pollination Adaptations.

• Brightly coloured petals with scented flowers.
• Big sticky pollen grain to attack to the insects.
• Stigma is also sticky so pollen will stick to it.

Wind Pollination Adaptations.

• Small, dull flower petals. No strong scent. A large feathery stigma.
• A lot of pollen grains. Long filaments that hang the anthers outside the plant.

Fertilisation

• A pollen grain lands on the stigma.
• A pollen tube grows out from the pollen grain and down through the style to the ovary and into the ovule.
• A nucleus from the male gamete moves down the tube to join with the female gamete.
• Fertilisation is when the two gametes fuse together to make a zygote.
• Each fertilised egg forms a seed.

Conditions for germination - Water and Temp (Enzymes), Oxygen (Respiration) 

A developing seed contains an embryo and a store of food reserves wrapped in a hard seed coat. It gets glucose for respiration from its own food stores.Once it has grown it can get its own food.

Natural Asexual - Runners    Artificial Asexual - Cuttings.

Male reproductive system

• Urethra - a tube which carries urine and sperm to exit the body.
• Erectile Tissue - Swells when filled with blood to make the penis erect.
• Testis - Where the sperm is made.
• Glands - Produce the liquid added to sperm.
• Sperm Duct - Tube that carries sperm from the testis towards the urethra.

Female Reproductive System

• Fallopian Tube - A tube that carries the ovum from the ovary to the uterus.
• Uterus - The organ where an embryo grows.
• Vagina - Where the sperm is deposited.
• Cervix - the neck of the uterus.
• Endometrium - has a good blood supply for implantation of an embryo.
• Ovary - the organ that produces ova and sex hormones.

Once the embryo has implanted the placenta develops - this lets the blood of the embryo and blood of the mother get very close allowing an exchange of food, oxygen and waste.

The amnion membrane forms - this surrounds the embryo and is full of amniotic fluid. Amniotic fluid protects the embryo against knocks and bumps.

Sexual Characteristics at puberty

Men - Hair on body and face, muscles, penis and testicles enlarge. Sperm production. Deepening of voice.

Woman - Hair on underarms and pubic area. Hips widen. Development of breasts. Ovum release and the start of periods.