Seed Plants Ch12.3 7th Pdf

Seed Plants Chapter 12 Section 3

Objectives: 

Describe 3 ways that seed plants differ from seedless plants

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Describe the structure of seeds

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Compare angiosperms & gymnosperms

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Explain the economic & environmental importance of gymnosperms & angiosperms

FYI: The Millennium Seed Bank Royal Botanic Gardens in Kew, England ◦ Collecting seeds from 24,000 plant species around the world ◦ 50,000 species may become extinct in the next 30 years ◦ Ensures the survival of plants that stabilize soil, provide food, medicine, and building material

FYI: Sea Bean (genus Mucuna) Largest seed pod in the world  Floats from river to ocean, 1000’s of miles before it is washed to shore 

http://waynesword.palomar.edu/images/mucuna4b.gif

http://www.ncaquariums.com/askaquarium/ataimg/seabeans.jpg

Seed Plants: 

2 groups of vascular plants that produce seeds: ◦ Gymnosperms  Trees & Shrubs that do not have flowers or fruit

◦ Angiosperms  Have flowers and seeds that are protected by fruit

Characteristics of Seed Plants 

Similarities: seed and seedless plants both alternate between a 2 stage life cycle ◦ Sporophyte ◦ Gametophyte

Characteristics of Seed Plants: 

Differences: ◦ Produce seeds; nourish and protect young sporophytes ◦ Gametophytes do not live independently of the sporophyte; tiny; form within the reproductive structures of the sporophyte ◦ The sperm of seed plants do not need water to reach an egg; form inside pollen – can be transported by wind or animals

Pollen: 

The tiny granules that contain the male gametophyte of seed plants

Seed Plants: 

Because of these characteristics, seed plants can live just about anywhere!

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Most common plants on Earth today

The Structure of Seeds: 

A seed forms after fertilization

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3 Parts: ◦ Young plant: Sporophyte ◦ Stored food: Cotyledons (seed leaves) ◦ Seed coat: surrounds and protects the young plant

Seed Structure:

http://www.uen.org/utahlink/tours/admin/tour/14719/14719lr001135.gif

The Structure of Seeds: 

Advantages over seedless plants: ◦ Young plant uses the stored food in the seed ◦ Can be spread by animals (more efficient)

Gymnosperms: Do not have flowers or fruit  Seeds are usually protected by a cone  4 Groups: 

◦ ◦ ◦ ◦

Conifers Ginkgoes Cycads Gnetophytes

Importance of Gymnosperms: 

Conifers: used for building materials, paper products, anti-cancer drugs

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Pine trees: produce resin (used to make soap, turpentine, paint, ink)

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Gnetophytes: anti-allergy drugs

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All are popular in gardens and parks

Gymnosperms:

Gymnosperm Life Cycle: 

Most familiar gymnosperm: conifer (“cone-bearing”) – have male & female cones

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Spores of each type of cone become tiny gametophytes

Gymnosperm Life Cycle: 

Male gametophytes are found in pollen (pollen contain sperm)

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Female gametophytes produce eggs

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Transfer of pollen from male to female cones = pollination

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Fertilized egg develops into a young sporophyte within the female cone

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Released under special circumstances (ex: forest fire)

Gymnosperm Life Cycle:

http://img.sparknotes.com/figures/9/9f79f1dbce762884bf644e4ac8450061/gymnospermlifecycle.gif

Angiosperms: 

Vascular plants that produce flowers and fruits

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Most abundant plants today

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235,000 species

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In almost every land ecosystem

Angiosperm Reproduction: 

Flowers help angiosperms reproduce ◦ Some depend on the wind for pollination ◦ Others have flowers that attract animals

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Fruits surround and protect seeds ◦ Depend on the wind to carry them ◦ Other fruits attract animals to eat them or are carried (ex: burrs)

2 Kinds of Angiosperms: 

2 Classes of Angiosperms

◦ Monocots ◦ Dicots

Monocots: One cotyledon Leaves with parallel veins Flower parts in threes Scattered bundles of vascular tissue Ex: Grasses, orchids, onions, lilies, palms

Monocots:

http://www.agen.ufl.edu/~owens/age2062/OnLineBiology/OLBB/www.emc.maricopa.edu/faculty/farabee/BIOBK/monocots_1.gif

Dicots: 2

cotyledons  Ex: roses, cactuses, sunflowers, peanuts, peas  Leaves with branching veins  Bundles of vascular tissue are in a ring

Dicots:

http://www.agen.ufl.edu/~owens/age2062/OnLineBiology/OLBB/www.emc.maricopa.edu/faculty/farabee/BIOBK/DICOTS.gif

Importance of Angiosperms: Provide food for land animals  Part of food chain  Major food crops for people (corn, rice, wheat)  Oak trees (building materials)  Cotton or flax (clothing or rope)  Medicines, rubber, perfume oils 

Angiosperms:

Quick Quiz: 

How are gymnosperms and angiosperms different?

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How are flowering plants important?