Plants 8.4 Gymnosperms and Angiosperms

POINT > Describe gymnosperm characteristics POINT > Identify 4 types of gymnosperms POINT > Describe gymnosperm reproduction POINT > Describe angiosperm characteristics POINT > Describe the structure and function of flowers and fruits POINT > Identify uses of seed plants

POINT > Describe gymnosperm characteristics Gymnosperm means “naked seed”: The seed is not surrounded by a fruit The leaves of gymnosperms are needle-like Most gymnosperms keep their leaves all year around, so they are sometimes called “evergreens” The gymnosperms were the first plants with seeds The sequoia are the world’s largest single-stem plants

POINT > Describe gymnosperm characteristics The sequoia are the world’s largest single-stem plants

POINT > Identify 4 types of gymnosperms 1. The largest group of gymnosperms are the conifers 2. Cycads also have cones and grow in tropical areas 3. Gingkoes now grow only where planted by humans 4. Gnetophytes grow in very hot places and can live for over 1000 years Gymnosperms dominated the planet until plants with flowers and fruits evolved

CHECK: What are 3 characteristics of gymnosperms? What are 4 types of gymnosperm? What is the world’s largest plant?

POINT > Describe gymnosperm reproduction Most gymnosperms have cones: the structures that produce egg and sperm cells Most of these plants have female cones (egg production) and male cones (sperm cell production)

POINT > Describe gymnosperm reproduction The sperm cells are enclosed inside pollen grains Pollen is carried by the wind to the female cones Pollination is when the pollen grain reaches the female part of the plant Gymnosperms were the first plants to have pollen

POINT > Describe gymnosperm reproduction Fertilization occurs when the sperm cell combines with the egg cell in the female cone The seed develops inside the female cone and is dispersed by the wind (no fruit)

CHECK: What are cones? What is pollination? How is pollen carried to the female cones in gymnosperms?

POINT > Describe angiosperm characteristics Angiosperms are the most widespread group of plants Angiosperms have two characteristics that make them very successful: Flowers have colors and smells to attract insects and other animals for pollination Fruits that surround the seed and help the plant disperse seeds far away

POINT > Describe the structure and function of flowers and fruits The flower is the reproductive part of angiosperms Flowers have both male and female structures

POINT > Describe the structure and function of flowers and fruits Pistil

POINT > Describe the structure and function of flowers and fruits The stamen is the male part of the flower The stamen includes the filament and anther Sperm cells are produced in the anther Pistil

POINT > Describe the structure and function of flowers and fruits The pistil is the female part of the flower The pistil includes the stigma, the style and the ovary Egg cells are produced in the ovary. The stigma is where the pollen sticks to the female part of the plant (pollination) Pistil

POINT > Describe the structure and function of flowers and fruits The petals are usually the most colorful, to attract pollinators The sepals are usually green and protect the developing flower Pistil

CHECK: What are two important characteristics of angiosperms? What is a flower? What is the stamen? Where is pollen produced? What is the pistil? Where are egg cells produced? What do petals do for the flower?

POINT > Describe the structure and function of flowers and fruits Reproduction in angiosperms: Pollination: pollen from the anther reaches the stigma Pollinators, such as insects, birds and bats are attracted to flowers to get nectar ( a sweet liquid)

POINT > Describe the structure and function of flowers and fruits Reproduction in angiosperms: 2. Fertilization: the sperm cell reaches the egg cell in the ovary The ovary develops into a fruit around the seed

POINT > Identify uses of seed plants Humans use angiosperms in many important ways: Food: fruits, vegetables, cereals Medicines: Many important medicines come from flowering plants and trees Clothing: Cotton and other fibers Building materials: for homes and furniture

CHECK: What is pollination? What are 3 example of pollinators? What is fertilization? What are ways we use angiosperms?

Homework: Read pages 272-281 S.A. page 281 #1-3 GRAS pages 115-117