Notes on chapters of Botany covering the topics: Multicellular Algae, Mosses/Ferns, Plants with Seeds, Seed Plant Reproduction, Plant Structure, and Control of Plant Growth/Development

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Chapter 20: Multicellular Algae

Characteristics of Algae

-Algae are photosynthetic organisms

-Live in streams, ponds, lakes, oceans, and swamps

-Must live in or near a source of water

-Algae lack an internal system

-Algae lack an internal system of tubes to move water and materials from one part to another

-Water in which algae live provides CO2, oxygen, nutrients, and carries away wastes

-Can be multicellular or unicellular

-Algae cells have cell walls

-Algae have chlorophyll a and other chlorphylls

-Reproductive cycle alternates between sexual and asexual

-Dispute over whether kingdom Protista or kingdom Plantae

Adaptations of Algae to Life Under Water

-Do not need to worry about drying out

-Many algae have very think, leaflike structure that's not waterproof

-Structures can exchange nutrients, oxygen, CO2 with the water

-Do not need stemlike structures

-Water keeps them supported

-Sexual reproduction is easier in water

-Sex cells can swim through water

Chlorophyll and Accessory Pigments

-Major problem for water plants is lack of light for photosynthesis

-Sea water absorbs red and violet which is what chlorophyll a uses best

-Light becomes dimmer and bluer in color as depth of the water increases

-Algae have evolved various forms of chlorophyll

-All have a

-B, C, D

-Accessory pigments are light absorbing compounds

-Absorb different wavelengths of light than chlorophyll absorbs

-Pass on the energy they absorb to the photosynthetic structures

-Reflect different wavelengths = give algae a wide range of colors

Groups of Algae

-Colors provided by chlorophyll and accessory pigments and form in which food is stored are used to classify algae

Chlorophyta - The Green Algae

-Green algae live primarily in moist areas on land and in fresh water

-Some live in oceans

-A colony is a group of cells that are joined together and show few specialized structures, or...