Reproduction

Step 1: In asexual reproduction offspring arise from one parent. Step 2: Accurate copying preserves parent like traits. Step 3: Too much similarity can be a limitation in a changing environment.

Step 1: Genetic information passes during reproduction. Step 2: A small copying error can create a new difference. Step 3: If it is not harmful it can contribute to variation.

Step 1: Some unicellular organisms can form a covering in unfavourable conditions. Step 2: Repeated division inside forms many cells. Step 3: They can come out when conditions become favourable.

Step 1: The nucleus contains genetic information. Step 2: Binary fission produces two daughter cells. Step 3: Nuclear division ensures both receive required information.

Step 1: In Hydra a small bud forms on the parent body. Step 2: In Amoeba the whole cell divides. Step 3: Both involve one parent but the methods differ.

Step 1: In complex organisms body parts perform different functions. Step 2: Every part cannot form the whole body. Step 3: Therefore complete regeneration is difficult compared with simpler organisms.

Step 1: In fragmentation broken pieces can become independent organisms. Step 2: In regeneration an organism can reform lost parts. Step 3: They are related but not exactly identical.

Step 1: Light spores can travel far by air. Step 2: Thick walls protect them in difficult conditions. Step 3: In favourable conditions they can form new fungi.

Step 1: Not all spores get favourable conditions. Step 2: If many spores are produced some may reach a suitable place. Step 3: This increases the chance of new fungal growth.

Step 1: Vegetative propagation forms a new plant from one parent part. Step 2: Good traits can be maintained quickly. Step 3: But high similarity can create shared weakness to disease.

Step 1: Seedless plants are difficult to multiply by seeds. Step 2: Vegetative propagation can use root stem or leaf to form a new plant. Step 3: Hence it is useful for such crops.

Step 1: Eyes on potato are like buds. Step 2: Buds are generally a stem feature. Step 3: Their sprouting shows that potato is a modified stem.

Step 1: Genetic information comes from two parents. Step 2: Their fusion creates new combinations. Step 3: Different combinations may help some offspring in changing conditions.

Step 1: Pollination only transfers pollen to the stigma. Step 2: For fertilisation the male gamete must reach the ovule. Step 3: If the tube fails fertilisation and seed formation will not occur.

Step 1: In pollination pollen reaches the stigma. Step 2: In fertilisation male and female gametes fuse. Step 3: Fertilisation can still fail after pollination so they are different.

Step 1: Insects visit flowers. Step 2: Pollen can stick to their bodies and reach another plant. Step 3: Genetic information from different plants can increase variation.

Step 1: Self pollination needs proper timing of pollen and stigma. Step 2: If the pistil is not ready pollen may not settle properly. Step 3: Thus self pollination or further fertilisation can be affected.

Step 1: Fertilisation occurs in the ovule. Step 2: The embryo develops inside the ovule and the ovule becomes seed. Step 3: The ovary grows into fruit and contains the seeds.

Step 1: The ovule contains the female gamete. Step 2: After fertilisation zygote and then embryo form. Step 3: Without embryo normal seed formation does not occur.

Step 1: Water makes the seed swell and become active. Step 2: Air helps the embryo respire. Step 3: Suitable temperature allows internal growth reactions to occur.

Step 1: Sperm production is sensitive to temperature. Step 2: The scrotum keeps testes slightly cooler than body temperature. Step 3: This creates suitable conditions for sperm formation.

Step 1: Testes produce sperms. Step 2: Sperm duct provides the path to carry them forward. Step 3: If the path is blocked sperms cannot reach the ovum.

Step 1: Ovary produces the female gamete. Step 2: After fertilisation the embryo needs a safe place for development. Step 3: The uterus provides this place.

Step 1: In a normal cycle ovum may be released. Step 2: Fertilisation usually occurs in the oviduct. Step 3: If the oviduct is blocked gametes cannot meet.

Step 1: After fertilisation the zygote divides into an embryo. Step 2: The embryo must attach to the uterine lining. Step 3: Without attachment it cannot get nourishment and protection.