Table of ContentsPlant StructuresPlant ReproductionAnimal Reproduction and FertilizationDevelopment and Growth

Plant and Animal Life Cycles

Plant Structures and Pollination Brain Pop

http://www.brainpop.com/science/cellularlifeandgenetics/pollination/preview.weml

Roots

• Roots anchor a plant in the ground, absorb water and minerals from the soil, and sometimes store food.

• The more root area a plant has, the more water and minerals it can absorb.

Types of Roots

• There are 2 main types of root systems, a fibrous root system and a tap root.

• A fibrous root system consists of many similarly sized roots that form a dense, tangled mass.

• A taproot system has one long, thick main root with many smaller roots branching off of the main root.

Which is an example of a Fibrous root and which is a Tap Root?

Root StructureRoots have many structures.

The root cap protects the root from injury as it grows through the soil.

Root hairs absorb water and help anchor the root to the soil.

In the vascular tissue of the root xylem brings nutrients and water from the soil to the plants stems and leaves.

Phloem transports food made in the leaves to the root where it is used for food or stored.

Plant Structures

Stems – Pairs Compare

• What are 3 examples of different types of stems and how they are different from one another?

Stems

• Stems carry substances between the plant’s roots and leaves and provide support for the plant so that it can hold up the leaves and expose them to the sun.

• Some stems also store food. • Stems can be either woody or herbaceous. • Herbaceous stems contain no wood and are often soft.

Stem StructureThe woody stem of a tree contains many different structures. Sapwood is active xylem that transports water and minerals through the stem. What are the active xylem and phloem on the tree trunk?

Plant Structures

Annual Rings

• Tree rings are produced by xylem cells.• These cells are large, have thin walls, grow rapidly, and

produce a wide light brown ring when they form in the spring.

• The cells that form in the summer are small, have thick walls, grow slowly and produce a dark ring.

• A pair of light and dark rings represents one years growth. • In rainy years more xylem is produced making the rings

wide, but in dry years they are narrow.• This allows scientists to know when severe droughts have

occurred. • http://youtu.be/FAOYkx8E-Gc

Leaves

• Leaves capture the suns energy and carry out the food-making process of photosynthesis.

• The top and bottom surface layers of a leaf protect the cells inside.

• Between the layers of cells are veins that contain xylem and phloem.

• The surface layers of the leaf have small openings, or pores, called stomata.

• Stomata open and close to control when gases enter and leave the leaf.

• When the stomata are open, carbon dioxide enters the leaf, and oxygen and water vapor exit.

The Leaf and Photosynthesis

• The cells that contain the most chloroplasts are located near the leaf’s upper surface.

• Carbon dioxide enters the leaf through the open stomata and water is absorbed through the roots up the stem into the leaf’s xylem.

• During photosynthesis sugar and oxygen are produced from the carbon dioxide and water.

• Oxygen exits the leaf through the open stomata and sugar enters the phloem to travel throughout the plant.

Leaf StructureEach structure helps a leaf produce food.

Plant Structures

Controlling Water Loss

• The process by which water evaporates from a plant’s leaves is called transpiration.

• A plant can retain water by closing the stomata which often occurs when leaves start to dry out.

StomataStomata can slow water loss.

Plant Structures

Photosynthesis In Leaves

Brain Pop on Photosynthesis:http://www.brainpop.com/science/cellularlifeandgenetics/photosynthesis/preview.weml

How Do Seeds Become Plants?

• Inside a seed is a partially developed plant. • If a seed lands in an area where conditions are favorable, the

plant sprouts out of the seed and begins to grow. • A seed has 3 main parts: an embryo, stored food, and a

seed coat. • The young plant that developed from the zygote, or fertilized

egg, is called the embryo. • The embryo already has the beginnings of roots, stems, and

leaves. • The embryo stops growing when it is quite small.

How Do Seeds Become Plants?

• When the embryo begins to grow again it uses the food stored in the seed until it can make its own food through photosynthesis.

• It has one or more seed leaves, or cotyledons. • The outer covering of a seed is called the seed coat. • The seed coat protects the embryo and its food from drying

out. • This allows the seed to remain inactive for a long time. • In many plants seeds are surrounded by a structure called

fruit.

Plant Structures

Story of a SeedWhich is the seed’s embryo, cotyledons, and seed coat on the diagram?

Stem and root Stored

Food

What Are Some Ways In Which Seeds are Dispersed?

• Round Robin: Discuss with your group some possible ways in which seeds can be dispersed.

Seed Dispersal

• When animals eat fruit, the seeds inside the fruit pass through the animal’s digestive system and are deposited in new areas.

• Some seeds enclosed in barb-like structures hook onto fur or clothing.

• Some seeds fall off in a new area.• Water disperses seeds.• Wind disperses light weight seeds. • Some plants eject their seeds.

Germination

• Germination occurs when the embryo begins to grow again and pushes out of the seed.

• Germination begins when the seed absorbs water. • The embryo uses stored food to begin to grow and the roots

grow downward first. • Then, the stem and leaves grow upward.

What Are the Structures of a Flower?

• Flowers all have the same function, reproduction. • A typical flower contains sepals, petals, stamens and pistils. • The colors, shapes, and scents of most flowers attract insects

and other animals to ensure that pollination occurs. • Pollination is the transfer of pollen from male reproductive

structures to female reproductive structures. • With your partner answer the following question: What are

some examples of pollinators?

What are the Structures of a Flower?

• Sepals are small, leaf-like parts of a flower that protect the developing flower.

• Petals are the leaf-like colorful part of the flowers that attract insects.

• Stamens are the male reproductive parts of a flower. Pollen is produced in the anther, at the top of the stalk-like filament.

• Pistils are the female reproductive parts of the flower. They consist of a sticky stigma, a slender tube called a style, and a hollow structure called the ovary at the base.

• Ovaries protect the seeds as they develop and contains one or more ovules.

Structures of a Typical Flower

Plant Structures