Life Cycles of Plants and Animals

Science, Grade 3


Table Of Contents: Life Cycles of Plants and Animals

1. Plants
Plants are living things that need water, air, nutrients and sunlight to grow. There are two main kinds of plants - plants with flowers and plants without flowers. Plants with flowers include fruit trees and any plant with flowers. Plants without flowers include pine trees, mosses and ferns.
2. Main Parts of Plants
A plant has many important parts, such as roots, stem, leaves and flowers. Each part of the plant has different functions that make it possible for the plant to live.
3. Roots
Roots help support the plant by anchoring it into the ground. Roots have tiny hairs that absorb nutrients from the soil, which a plant needs to grow. These root hairs also take in water from the soil, which a plant needs to live and grow.
4. Stem
A plant's stem is used to support the plant. The stem allows the plant's leaves to reach above the soil so that they may take in the sunshine. A plant's stem carries the water and nutrients that are taken in by the plant's roots to the rest of the plant.
5. Leaves
Leaves are the parts of a plant where the plant's own food is made. They use sunlight, air, water and nutrients from the soil to make their own food through a process called photosynthesis.
6. Flowers
The main job of the flower of a plant is to make seeds. New plants grow from these seeds. Some plants form fruit to help protect their seeds.
7. What a plant needs to grow...
Plants need many essential things in order to grow, such as water, air, nutrients, sunlight, and warm temperature. Plants need their space too!
8. Germination
Germination is the process by which the plant embryo inside a seed grows and a seedling grows above the soil. A seedling is a young plant that is in its early stages of growth.
9. Plants have different life cycles...
Living things have different life cycles. A life cycle is the way a living thing grows and changes. A flowering plant's life cycle describes the steps a plant takes to grow and become an adult plant.
10. Bean Plant Life Cycle
A bean plant's life cycle includes four stages: 1. Seed - contains the embryo, which will develop into the plant; 2. Sprouting seed - germinates or grows root and stem; 3. Seedling- its first leaves make food 4. Mature plant- can make seeds that will begin the life cycle again!
11. Animals
There are many different kinds of animals. Animals are grouped into two kinds - animals with backbones and animals without backbones.
12. Animals with backbones
Animals with backbones include mammals, birds, fish, amphibians and reptiles.
13. Animals without backbones
Most kinds of animals do not have backbones. Animals without backbones include insects, worms, crabs, spiders and many others.
14. Animal Growth & Reproduction
Animals produce offspring in a variety of ways. For example, many animals have live births. The offspring develop inside the female parent which then gives birth to the live young. Other organisms, like chickens and frogs, lay eggs instead of having live births. Animal life cycles vary in how long they take.
15. Frog Life Cycle
Like all amphibians, frogs spend their lives near water because they must return to water to lay their eggs. The four stages of a frog's life cycle include: 1. Frog eggs are laid in water. 2. Tadpoles hatch from the eggs. They breathe with gills and swim using a tail. 3. The froglet still has part of its tail and starts to breathe using its lungs. 4. By the time a froglet becomes an adult, its tail is reabsorbed.
16. Butterfly Life Cycle
Butterflies and moths go through complete metamorphosis and undergo four stages of development: egg, larva (caterpillar), pupa (Chrysalis), and adult.
17. Dragonfly Life Cycle
Most insects go through complete metamorphosis, but some, such as dragonflies, go through incomplete metamorphosis. This life cycle includes three stages of development: egg, nymph, and adult.
18. Inheritance of Traits
Have you ever wondered why offspring , the young of a plant or animal, often look like their parents? This is due to the inheritance of traits, which means that parents pass on their traits to their offspring. Animals inherit traits such as the shape and color of their body parts. Plants inherit traits such as leaf shape and flower color.
19. Animal Variation Due to Inherited Traits
Some offspring may appear different than one or both parents. This is because the offspring receive traits from both parents resulting in a unique combination that is different from either parent. Variations in humans are height and eye color. A child's parents may both have brown eyes, yet the child could have blue eyes.
20. Variation Due to Environment
Characteristics of plants and animals can be affected by their surroundings, climate or diet. For example, if you eat too much you will become heavier, and if you eat too little you will become lighter. A plant in the shade of a big tree will grow taller as it tries to reach more sunlight.
21. Adaptation
An adaptation is a trait or characteristic that helps a living thing survive in its environment. For example, it takes special adaptations to be able to live in a very cold environment. Polar bears have thick blubber and dense fur to help keep them warm.