درس Structure And Functions Of Plants العلوم للصف الرابع منهج انجليزي

درس Structure And Functions Of Plants العلوم للصف الرابع منهج انجليزي

Plant Needs

The redwood trees that you saw in the lesson phenomenon and the two schoolyard plants you observed in the Inquiry Activity, Plant Parts, probably look very different. But they aren’t as different as you might think. All plants have the same basic needs and a set of typical structures

The basic needs of plants are air, water, sunlight, nutrients and space. Plants must live in an environment where their needs are met The air around Earth is a mixture of gases. Plants need one of these gases, carbon dioxide, to make food. They need another gas, oxygen, to break down the food. Plants have pores, or stomata, in their leaves that allow gases to move in and out of the plant

Plants use sunlight to make food. They use the energy from sunlight to make sugar. The sugar provides the energy plants need to survive. Some plants need more sunlight than others Plants use their leaves to gather sunlight

Plant Parts

Most plants have roots. stems, and leaves. These parts. or structures, help the plant meet its needs and carry out life functions

Roots

Plant roots take in water and dissolved nutrients from the soil. Roots also hold the plant in place. Some roots store food the plant has made

Stem

The stem supports the plant. It is also part of a plant’s transport system There are two types of stems: soft stems and woody stems. Soft stems are green and are flexible. Woody stems are hard and are often covered in bark. Tree trunks are examples of woody stems

Stems also allow materials to move inside the plant through a system of The tubes in the stems carry water and dissolved nutrients

Label a Diagram: Roots, Stems, and Leaves

Label the different parts of the plant. Then describe the functions of each of the plant parts below

hold the plant in place take in water and nutrients

Stems

support the plant transport materials

Leaves

capture light and are the site of gas exchange 

Talk About It

Use evidence to construct an argument that plant structures function to support survival stems

Plant Reproduction

Plants have many structures that are used for reproduction. Some of the structures are flowers, cones, seeds, and fruits

Flowers

Most flowers contain male and female parts. The stamen is the male part. It contains the anther, where pollen is produced. The pistil is the female part. It contains the ovary, where egg cells are produced. Insects, birds, and wind help move pollen. Fertilization occurs once the content inside the pollen joins the egg cells inside the ovary. Seeds develop after fertilization

Cones

Some seed plants reproduce with cones. These plants usually produce both male and female cones. The male cones pollen that is released into the wind

The female cones produce a sticky liquid that captures the Fertilization occurs in the female cone

Talk About It

Explain to a classmate the parts of a flower that help it reproduce. anther with

 

Plant Behavior

Plants have internal structures that enable them to react to changes in their environments

A change in an environment that causes an organism to respond is called a stimulus. The reaction or change in behavior of an organism is called a response. Plants respond to stimuli such as sunlight, water, and gravity

A plant responds to a stimulus by changing its pattern of growth. A plant’s response to water, gravity, light, and touch is called tropism

Plants respond to light by growing toward the light source. This response is known as phototropism. Most plant roots grow downward, the same direction as the pull of gravity, while most stems grow upward. This is called gravitropism. Roots sense water in the soil and grow toward or away from it. This response is known as hydrotropism. Some plants respond to touch, or contact with an object. by curling
around that object or clinging to it. This is known as thigmotropism

1. List the types of tropisms on the lines below. Identify and label the types of tropism shown in the photos on this page

phototropism gravitropism, hydrotropis thigmotropism

Do more research to find out how humans have affected each of the habitats that you chose Take notes

Sample answer: The northwestern coastal forest has been changed by logging. The North American desert is affected by habitat modification by humans and invasive species-

Communicate Information

6. How did the plants that you chose for your investigation differ Sample answer: The coast redwood is tall and has flat needles. The saguaro cactus expands to store water, and contracts as it uses its water supply. It has prickly spines and waxy skin— Engage in an argument from evidence to explain how the plants from your investigation have structures that function to survival in different environments

Sample answer: Most plants have roots stems, and leaves. They vary in shape and size. Plant structures are adapted to obtain the resources a plant needs to survive. Plants in moist habitats do not have thick stems because they have plenty of water compared to plants in desert areas

How is an organism’s structure related to its function ? Discuss your ideas with a partner  ure And Functions Of Plants

Extend It

How does human activity affect plants ? Think bæk to the Inquiry Activity. Survival in Different Habitats. Identify a negative effect that human activity has on plants. and propose a solution to the problem

Sample answer: Habitat modification and development threaten many plants in my area. Habitats are destroyed to make room for homes and businesses, and water is rerouted. To solve this problem, development can be limited to certain areas, and people can use native species to landscape their lawns. This will help to keep habitats from being broken up. By landscaping with native plant species, people will not need to worry about the climate and amount of water needed for the plants to survive

OPEN INQUIRY

What questions do you still have about plants’ structures and their functions Sample answer: Can a plant’s structure change over time

Plan and carry out an investigation or research to find the answer to your question