Plant Overview and Reproduction

Pre-AP Biology

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What Is a Plant?• Members of the kingdom Plantae• Plants are multicellular

eukaryotes • Plants have cell walls made of

cellulose. • Plants develop from multicellular

embryos and carry out photosynthesis using the green pigments chlorophyll a and b

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Overview of the Plant Kingdom

• Botanists divide the plant kingdom into four groups based on three important features:

1. Water conducting tissues2. Seeds3. Flowers

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The Plant Life Cycle

• Characterized by alternation of generations:the two generations are the haploid (N) gametophyte, or gamete-producing plant, and the diploid (2N) sporophyte, or spore-producing plant.

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Monocots and Dicots

• Monocots and dicots are named for the number of seed leaves, or cotyledons, in the plant embryo. Monocots have one seed leaf, and dicots have two seed leafs

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Reproduction of Seed Plants

Chapters 24

Life Cycle of Gymnosperms

• Reproduction in gymnosperms takes place in cones

• Male cones produce – pollen grains

• Female cones produce – ovules

http://glencoe.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::290::356::/sites/dl/free/007877814x/164155/431_Fig_11.swf::Gymnosperm%20Reproduction

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Flowers and Fruits• Angiosperms have unique

reproductive organs known as flowers.

Q: Why are flowers evolutionary adaptations?

A: they attract animals that pollinate them

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Structure of Flowers• Flowers are reproductive

organs that are composed of 4 kinds of specialized leaves

Sepals• Enclose the

bud before it opens, leaf-like

Petals• Brightly colored, attract

insects to flower

Stamen• Male reproductive

structure of flower, made of 2 parts

• Filament – long, thin, stalk that supports the anther

• Anther – makes pollen grains

Anther

Filament

Anther + Filament = Stamen

Pistil• Female reproductive

structure, made of 3 parts

Stigma• where pollen

grains land, sticky

Style• Connects stigma to ovary

Style

Ovary• swollen base of

the pistil where ovules are formed

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• Flowers contain ovaries, which surround and protect the seeds

• After pollination, the ovary develops into a fruit, which protects the seed and aids in its dispersal.

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Fruit • Ripened ovary, thick wall of

tissue that surrounds the seed

http://www.sumanasinc.com/webcontent/animations/content/angiosperm.html

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PollenPollen Grain• Contains the male gamete

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Pollination • The transfer of pollen from

the male gametophyte to the female gametophyte

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Seeds• An embryo of a plant that is

encased in a protective covering and surrounded by a food supply

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Embryo• Early development stage of a

sporophyte plant• The seed’s food supply

provides nutrients to the embryo as it grows

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Seed Coat• Surrounds and protects the

embryo and keeps the contents of the seed from drying out

• Can be specialized for dispersal

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Pollination• Most gymnosperms (some

angiosperms) are wind pollinated• Most angiosperms are pollinated

by animals• Insect pollination beneficial to

insects and other animals: provides them with food

• Plants also benefit: this method of pollination is more efficient

Seed Dispersal• Animals• Wind and water

Ultraviolet Flowers

http://www.naturfotograf.com/UV_flowers_list.html