Sexual reproduction

Sexual reproduction

DNA comes from two parents
offspring=blend of parents
fusion of gametes (sex cells)

Sexual reproduction advantages

Increases genetic variation → improve species

Can adapt to changing environmental conditions

Disease is less likely to affect the population

Sexual disadvantages

Takes time and energy to find mates

Difficult for isolated members of the species to reproduce

Can’t create colony

Many flowers can’t reproduce without pollinators

Sexual reproduction GV

There is a lot of genetic variation

Genetic variation = combo two parents DNA

Meiosis

cell division → FOUR daughter cells, each with HALF the normal amount of the DNA

Meiosis creates gametes (sperm and eggs) used in sexual reproduction.

9 stages

Fertilisation

fusion of male gamete (sperm/pollen) with female gamete (egg/ova) →   zygote.
Offspring = genetic characteristics from both parents

In animals, fertilization can occur outside/inside the female’s body.

• Sperm: meiosis in testes → male gametes

• Eggs/Ova: meiosis in ovaries→ female gametes

Pollination

the fusion of pollen (male gamete) with Ova (female gamete) → zygote. 

• Pollen (male gamete, from anther ) deposit on stigma = fertilization → seed production

• Pollen moves to plants ovary, which holds plants egg shell

• Pollen fertilize ova → zygote → seed

Gamete

sex cells produces by diff sexes, carry half of the DNA.
e.g sperm and egg/ova