Learn Class 3 Science - Plants and Animals

Plants

Our world is full of plants. Most plants have certain parts and attributes in common. There is also amazing diversity within the plant kingdom. This unit helps students understand the parts of plants and the functions of those parts. It explains photosynthesis as the process by which plants make their own food. It also explains how and why plants reproduce and grow, including the processes of pollination, fertilization, seed dispersal, and germination. The unit explains some of the key relationships between plants and animals. It also describes some of the many ways people use plants for both food and materials.

Adaptations in Plants

Examples of inherited characteristics in plants that can vary and change over time

these are traits that are consistent for the plant year to year

• Leaf shape (points to shed water)
• Growth rate (alpine plants grow quickly)
• Poison (milkweed-goat, red maple-horse)
• Bark thickness (dry vs. wet)
• Bad taste (greens, acorns, walnuts)
• Seed cover shape (for travel)
• Waxy leaf coating (wet vs. dry)
• Leaf drop (northern climates)
• Flower shape and color (pollinators)

Examples of non-inherited characteristics in plants that vary based upon that years environmental conditions (how much sunlight, minerals and water are available)

• Leaf size
• Fruit size
• Total plant size
• Fruit amount
• Growth rate
• Total plant shape (think trees)

Recognize plant behaviors

Plant behaviors are called Tropisms. These are the ways that plants respond to their environment. Below is a list of different plant tropisms. You may choose to use this term or not. Plant behavior is fine for 3rd grade.

• Geotropism – response to gravity- Plant roots grow in the direction of gravity and plant stems grow opposite to the pull of gravity
• Phototropism – response to light – Plant leaves and stems grow in the direction of the strongest light.
• Chemotropism – response to chemicals – Plants roots will grow toward minerals that they need and away from others that are harmful, such as salt.
• Thigmotropism – response to touch – Some plants are able to respond to touch, such as the Venus flytrap, morning glory, pea and squash family tendrils (when they touch something they grow in that direction and grab on to it)

Plant life cycle

Plants have a distinct life cycle. It goes as follows:

• Seed
• Seedling – germination is the name of this process
• Adult plant
• Flowering – pollination occurs here
• Seeds form
• Seed

Plant Parts

Plant parts and functions

Roots

Structure - Tap root, lateral root, Root hairs, root cap

Function - anchor plant – absorb nutrients – absorb water

Stems

Structure - Microscopic tubes

Phloem- carries the food (sap) (2 way flow) – living tissue

Xylem – carries the water (one way flow – up) – dead tissue (inside of the stem)

Function - support leaves and flowers – transport between roots and leaves

Leaves

Structure - Macro parts - petiole, midrib, margin, tip,

Microscopic parts – cuticle, epidermis, stomata, chloroplast

Function - Collect sunlight

Photosynthesis – (put together with light)Produce sugar in the chloroplasts by collecting sunlight and using it to combine CO2 and water to form glucose (sugar)

Flower

Structure - protective parts – receptacle, sepal, petal

Female parts - Pistil (stigma, style, ovary, ovule)

Male parts - Stamen (anther, filament, pollen)

Function - Collect sunlight

Produces fruit, but most important is seeds

photosynthesis

Photosynthesis is a very difficult topic for children (and adults) to understand, but the gist of it is that plants use sunlight to make sugar from Carbon dioxide and Water. Plants use sunlight for energy in a similar way that we use heat to change a cake batter into a cake (or sugar cookie batter into a sugar cookie)

Leaves contain structures in their cells called chloroplasts. Chloroplasts contain the chemical chlorophyll which through a rather involved process converts sunlight into an unstable chemical form of energy. This chemical (ATP) is then used to rearrange water and carbon dioxide so that it becomes glucose or sugar, which is used by the plant for energy (eaten if you will). The sugar can be stored for a long time and more importantly, can be eaten by animals. (Thus we are all eating different forms of sunshine!)

This trick is the beginning of almost all food chains on Earth. It is really an amazing feat and one that should cause students to be full of wonder. You can trigger a student’s curiosity by asking how plants eat food. Where is their mouth? How does it get food? Once you get to the answer that plants make their own food you can explain that if they could do this, then instead of going to the cafeteria for lunch, we would all march outside, lay down in the sun and make lunch. Then all the food we would need would be stored in our body.

To conclude

1. Plants make food by using sunlight, carbon dioxide and water
2. This is the beginning of almost all food chains on Earth
3. Humans depend upon plant photosynthesis for all our food.

Animals

Animals are found all over the world. There are different types of animals such as Insects, Birds, Reptiles and Mammals. They need food, water and shelter for their survival. Animals that stay with human beings are called as Pets. Animals staying in forests like Lion, Tiger, Giraffe, Elephants, Bear are known as Wild Animals. Animals like cows, hens, sheep which are useful to mankind are known as Domestic Animals.

Your third grader will love learning about animals — different species, habitats where they live, how they live, what they eat, and how they move!

Your child can prepare on the following topics

Animal habitats

Do sharks build nests and live in trees? Maybe. Maybe not.

In this chapter, your child will connect each animal to its natural habitat.

How animals adapt to habitat

How has the dormouse adapted to its home? How about the mole?

In this science chapter, your child will look at drawings and read synopses of four animals. Then they will consider and come to conclusions about those animals adapting to their different environments.

How does it move?

Animals can move on their own, but in different ways.

In this chapter, your child will connect each animal to the word that describes how it moves, such as swim, crawl, or fly.

Type of animal

Mammal, reptile, bird, fish? There are many different types of animals, and some belong to the same group.

In this science chapter, your child learns that common features help identify different types of animals, such as mammals.

Learning Videos for 3rd Grade Science - Plants and Animals