(P5)科學1

Plants reproduce through various methods including:

1. Sexual Reproduction: Involves the fusion of male and female gametes, often facilitated by pollinators.
2. Asexual Reproduction: Includes methods like budding, fragmentation, and vegetative propagation, where new plants grow from parts of the parent plant.
3. Pollination: The transfer of pollen from the male anther to the female stigma, which can occur through wind, water, or animals.

Animals reproduce primarily through two methods:

1. Sexual Reproduction: Involves the combination of genetic material from two parents, resulting in offspring with genetic variation.
2. Asexual Reproduction: Some animals can reproduce without mating, such as through budding or parthenogenesis, where an egg develops into an organism without fertilization.

Chicks develop from fertilized eggs using nutrients in the eggs and hatch out when they have developed enough.

Reproduction is crucial for several reasons:

• Continuation of Species: It ensures the survival of a species by producing new individuals.
• Genetic Diversity: Sexual reproduction promotes genetic variation, which is essential for adaptation and evolution.
• Population Maintenance: Reproduction helps maintain population sizes and ecological balance within ecosystems.

The stages of growth for a tomato plant include: 1. Seeds 2. A seed sprouts 3. Roots 4. A stem and leaves grow 5. The plant grows taller 6. Flowers grow 7. Flowers wilt 8. Fruits grow

Seeds can grow into a new tomato plant.

Seeds are usually found in the flesh of the fruit.

Violets can reproduce by their leaves.

Sweet potatoes can reproduce by their roots.

Strawberries can reproduce by their stems.

1. Pollen sticks to an insect.

2. The insect carries the pollen to another flower.

3. The flower which received the pollen wilts.

4. The ovary starts growing.

5. The ovary grows into a fruit.

6. Seeds develop in the fruit.

Pollination is the transfer of pollen from a stamen to a pistil. After pollination, the ovary of the flower grows into a fruit, which contains seeds.

Flowering plants spread their pollen by animals or wind.

Flowers attract animals for pollination by using nectar, colourful petals, and sweet smells.

Plants spread their seeds through various methods:

1. By wind - Seeds are light and can be carried away by the wind.
2. By water - Some seeds can float and travel on water to new locations.
3. By bursting - Certain plants burst open their seed pods to release seeds.
4. By animals - Animals eat fruits and either spit out or excrete the seeds, helping in their dispersal.

Fruits and seeds have specific features that aid in their dispersal:

• Sweet fruits attract animals, which eat them and help spread the seeds.
• Air-filled fruits allow seeds to float on water.
• Lightweight seeds can be carried by the wind.
• Hooks on seeds enable them to cling to animal fur for transport.

Flowers play a crucial role in plant reproduction by:

1. Producing pollen through stamens.
2. Attracting pollinators with nectar and colorful petals.
3. Facilitating fertilization when pollen reaches the pistil, leading to fruit development.

Flowering plants reproduce primarily through pollination, which can occur via:

• Animal pollinators attracted by nectar and scents.
• Wind that carries pollen from one flower to another.

The different methods of seed dispersal include:

1. Birth
2. Growth
3. Ageing
4. Death

Animals become extinct eventually if they do not reproduce.

A cow and a bull mate, the bull's sperm fertilises an egg inside the cow's body, forming an embryo that develops until birth.

Mothers feed their newborn babies with their milk.

Reproduction helps maintain animal populations and prevents extinction by ensuring the continuation of species.

The hen lays eggs and covers them with her wings and body to keep them warm during development.

No, chicks cannot hatch from market eggs because those eggs are not fertilized.

Examples include frogs, butterflies, ducks, and crocodiles.

Similarities include the purpose to prevent extinction, the formation of a fertilized egg, and the new generation sharing physical features with their parents.

Animals that lay eggs include bees, fish, and turtles.

Ducks grow bigger and undergo a big change in form.

Giant pandas grow bigger and undergo a small change in form.

Rhinoceroses grow bigger and undergo a small change in form.

Butterflies grow bigger and undergo a big change in form.

Frogs grow bigger and undergo a big change in form.

The stages of the life cycle of animals include birth, growth, ageing, and death.

Some animals reproduce by mating, where a sperm fertilizes an egg inside the female's body. The fertilized egg develops into an embryo that receives nutrients from the mother, and when it has developed enough, the mother gives birth to the baby, often feeding it with her milk. Examples include sheep and giant pandas.

Some animals reproduce by mating, where a sperm fertilizes an egg of the female. The fertilized egg uses nutrients in the egg to develop outside the mother's body, and the baby hatches when it has developed enough. Examples include chickens and turtles.

Reproduction is important for animals as it helps prevent extinction of species by ensuring the continuation of their population.

Some animals, such as butterflies and frogs, undergo significant changes in size and form as they grow, which is known as metamorphosis.