Reproduction

Step 1: Placenta provides close contact between mother and embryo. Step 2: Nutrients and oxygen can pass across thin surfaces to the embryo. Step 3: Wastes can also pass from embryo to mother.

Step 1: Information for traits is present in genetic material. Step 2: Before offspring form this information is copied and passed on. Step 3: Therefore offspring resemble parents.

Step 1: Genetic information is necessary for forming offspring. Step 2: This information is passed on by copying. Step 3: Without copying a new organism cannot form properly.

Step 1: Cutting is a method of vegetative propagation. Step 2: A part of the same plant forms a new plant. Step 3: Therefore new plants are highly similar to the parent.

Step 1: Many flowers attract insects. Step 2: Pollen grains may stick to the insect body. Step 3: When insects visit another flower pollen can reach the stigma.

Step 1: Pollination only means pollen reaching the stigma. Step 2: For fertilisation male gamete must reach the female gamete in ovule. Step 3: If this does not happen fertilisation will not occur.

Step 1: Asexual reproduction does not need a mate. Step 2: One parent alone can form new organisms. Step 3: Thus numbers can increase rapidly in favourable conditions.

Step 1: Sexual reproduction combines information from two parents. Step 2: This creates new combinations of traits in offspring. Step 3: Variation can be useful in changing environments.

Step 1: Amoeba reproduces by binary fission from one parent so it is asexual. Step 2: In humans male and female gametes fuse. Step 3: Therefore human reproduction is sexual.

Step 1: Reproduction forms new organisms. Step 2: Offspring may show small differences. Step 3: These differences can be useful in changing conditions.

Step 1: Sexual reproduction forms male and female gametes. Step 2: Fusion of these gametes creates a new mix of genetic material. Step 3: Therefore offspring may show more variation.

Step 1: Asexual reproduction involves only one parent. Step 2: Offspring receives genetic material from that parent. Step 3: That is why offspring looks similar to the parent.

Step 1: In binary fission one cell divides into two. Step 2: In multiple fission one cell can form many new cells. Step 3: So the main difference is the number of offspring formed.

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

Step 1: A small bud forms on the body of Hydra. Step 2: It grows into a small Hydra-like organism. Step 3: When fully developed, it can separate from the parent.

Step 1: In fragmentation the body breaks into pieces. Step 2: Each piece can become a new organism only if it is living and able to grow. Step 3: Therefore only capable fragments form new offspring.

Step 1: Rhizopus forms spores inside sporangia. Step 2: Spores are light and can spread. Step 3: Under suitable conditions they develop into new fungi.

Step 1: Some organisms like Planaria can form a new organism from a small piece. Step 2: In more complex organisms, repair may occur but a whole organism may not form. Step 3: Therefore regeneration ability is not the same in all organisms.

Step 1: In vegetative propagation, a new plant forms from a plant part. Step 2: New plants can keep traits similar to the parent. Step 3: So it is useful for multiplying good varieties quickly.

Step 1: In Bryophyllum, small buds form on leaf margins. Step 2: These buds can fall on soil and form new plants. Step 3: So it is an example of vegetative propagation.