Seed Plants Angiosperms Gymnosperms

Evolution Of Land Plants REMEMBER: Terrestrial plants evolved from a green algal ancestor The earliest land plants were nonvascular, spore producers (bryophytes) Ferns were the 1st vascular, spore producing plants Gymnosperms & angiosperms were the 1st vascular, seed plants copyright cmassengale

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Characteristics of Seed Plants Multicellular Autotrophic Alternation of Generations Reproduce by Seeds Vascular tissue for transport Heterosporous – make female megaspores & male microspores Dandelion dispersing seeds copyright cmassengale

Reasons for Success on Land Waxy cuticle Stomata with guard cells to open & close Gametes protected in tissue called Gametangia Pollen tube to transfer sperm to the egg instead of water Seeds protect developing embryo & contain food copyright cmassengale

Gymnosperms (“gymno” means naked + “sperma” means seed) Have cones for reproduction instead of flowers 4 Types Cycad - look like ferns except they have seeds Ginkgo - very large trees found mainly in China

Gymnosperms Conifers: seeds are in cones or berrylike structures Gnetophytes: shrubs and climbing vines

Significance of gymnosperms Ecological importance: Provide food and habitat for wildlife Forests prevent soil erosion Reduce greenhouse-effect gasses Economic and commercial importance: Lumber for wood, paper, etc. Resins – wood, furniture, etc. Ornamental plants (trees, landscaping) Food – pine nuts (pesto, etc.) copyright cmassengale

Angiosperms Angiosperm means “angio-” means vessel + “sperma” means seed Have flowers Have fruits with seeds Live everywhere – dominant plants in the world 260,000 species (88% of Plant Kingdom) Angiosperms are the most successful and advanced plants on earth

Sepals sepal The sepals protect the flower before it opens.

Petals The petals attract pollinating insects with their bright color and attractive scent.

Male Parts The stamens are the male structures of the flower. Made up of two parts.

Male Parts Anther: top part of the stamen, that makes pollen. Filament: this is the stalk of the Anther

Female Parts Pistil is the female structure of flower that has 3 parts.

Female Parts Stigma: Style: stigma The pollen from another flower collects on the stigma’s sticky surface. Style: raises the stigma away from the Ovary

Female Parts Ovary protects the ovules(egg). Once fertilization has taken place it will become the fruit.

Write the correct words in the boxes: stamens, stigma, petals, ovary, sepals pollen sticks to this where the seeds grow 5 1 these attract insects where the pollen is made You might like to stop the show here and print out this slide. If you are using the Powerpoint version, go to Format, Background, Background Fill, and choose white, then click on Apply. This will change the background of this slide only to white so that you can print more economically. Change back to the original colour before you show the slides again. The children could now examine some flowers, identifying the parts, looking at them through a hand lens etc. When you think they are ready to move on to pollination, show the slides again from the beginning for revision, or start at the first pollination slide. 2 4 These protect the flower before it opens 3

PLANT REPRODUCTION

Plants Reproductive Structures Cones: Gymnosperms Female cones contain the ovules which contains the egg cell Male cones contain pollen which are like sperm cells Flowers: Angiosperms Pistil: female part of flower Stamen: Male part of flower

Pollination Insects visit flowers to search for nectar – their food. But the flowers use the insects for their own purposes!

Pollen gets stuck on the insect’s legs. As the insect probes for nectar, its body rubs against the stamens. Pollen gets stuck on the insect’s legs. You can often see bees with a heavy load of yellow pollen on their hind legs.

Pollination pollination. When the insect visits another flower of the same type, the pollen will stick to the pistal. This is called pollination.

Fertilization The pollen travels to the ovary, where it joins with an ovule. This is called fertilization.

Seeds Seeds: the fertilized egg Seed Structure: consists of a seed coat, a young plant, and stored food

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copyright cmassengale Monocot vs. dicot Angiosperms are divided into monocots and dicots As the zygote grows into the embryo, the first leaves of the young sporophyte develop and are called as cotyledons (seed leaves) Monocots have one cotyledon (corn, lily, etc). Dicots have two cotyledons (bean, oak, etc). copyright cmassengale

Comparing monocot vs. dicot plants FEATURE MONOCOTS DICOTS Cotyledons 1 2 Leaf venation parallel broad Root system Fibrous Tap Number of floral parts In 3’s In 4’s or 5’s Vascular bundle position Scattered Arranged in a circle Woody or herbaceous Herbaceous Either copyright cmassengale

Summary: Monocot vs. dicot copyright cmassengale

Types of Seeds

Types of Seeds

Seeds The seeds develop inside the ovary, which grows to become the seed pod or fruit.

Seed Dispersal The seeds are dispersed; some by animals, some by the wind, some by explosion and some by water.

It begins when seed absorbs water & breaks seed coat (testa) Embryo uses stored food of cotyledons to begin growing

copyright cmassengale Fruits Form when ovary with ovules (eggs) ripens May be dry and hardened (nuts) May be enlarged and fleshy (berries, apples, tomatoes) Used to help disperse seeds copyright cmassengale