Plants Chapter 19 & 20 The origin of plants from algae Desended from Charophytes (multicellular green algae) Live around edges of lakes and ponds Some ancient charophytes may have lived in shallow-water habitats that occasionally dried out Natural selection favored algae that could survive the dry periods Adaptations enabled permanent plant life on dry land 475 million yrs ago What are plants? Multicellular Autotrophic Embryo develops within a mother plant Eukaryotic Mosses, hornworts, liverworts 19 2 (phyla) divisions in plants 1. Bryophytes- do NOT have transport tissue called vascular tissue, thus are nonvascular plants 2. Tracheophytes- do have vascular tissue, so are called vascular plants Flowering Plants Ferns conifers Warm-up: (solo on scratch paper) Identify the 2 phyla/divisions of plants Identify the characteristic that separates plants into these 2 divisions Identify major examples of plants that belong to each division 19 Bryophytes Nonvascular plants grow close to the ground to absorb water and nutrients. Seedless plants rely on free-standing water for reproduction. Liverworts, Hornworts Mosses 19 3 Kinds of Tracheophytes Pteridophytes : Gymnosperms Angiosperms 19 Tracheophyte Facts Adaptations of tracheophytes to life on land 1. P- protection from drying out 2. E- exchange of gases through leaves 3. T- transport substances 4. S- support 19 Plants have adaptations that allow them to live on land P-protection from drying out A cuticle allows plants to retain moisture. waxy, waterproof layer – holds moisture in 19 Plants have adaptations that allow them to live on land. stoma E-Exchange of gases on leaves Stomata are tiny holes in the lower epidermis. Guard Cells- open & close stoma Gurard cell 19 Plants have adaptations that allow them to live on land. T- Transport by Vascular Tissue – Xylem: transports water and minerals up from roots to leaves – Phloem: transports food (glucose) from leaves to roots and shoots xylem phloem water and mineral nutrients sugars 19 Plants have adaptations that allow them to live on land. S- support by cellulose and Lignin lignin plant cells – Allows plants to grow upright – hardens cell walls of some vascular tissues – provides stiffness to stems Bryophytes Nonvascular plants grow close to the ground to absorb water and nutrients. Seedless plants rely on free-standing water for reproduction. Liverworts, Mosses, and Hornworts VIDEO Alternation of Generations: The sex life of Bryophytes • What is meant by “Alternation of Generations”? • What is the difference between gametophytes and sporophytes? www.brainpop.com/science/diversityoflife/seed 19 Tracheophyte #1 lessplants/ Pteridophytes (Club mosses and ferns) are seedless vascular plants. Characteristics/Adaptations: Vascular tissue Seedless Ferns, Club Mosses, and Horsetails Club Moss Fern Horsetails 19 Ferns Sori form under the fronds Rhizoids Rhizomes Fiddlehead Video Fern Life Cycle: • What are Rhizoids • What is the difference btwn antheridium and archaegonium? • What is the function of anteridiogen? Tracheophyte #2 19 Gymnosperms www.brainpop.com/science/diversityoflife/seedplants/ Plants that bear seeds that are “Naked” (not enclosed by an ovary) can reproduce without free-standing water, via pollination – ADAPTATIONS – Vascular Tissue – Pollen Grains (male gametophyte) – Naked Seeds (embryo & food supply) – seeds allow plants to disperse to new places video Vascular Plants 19 Gymnosperms do have naked seeds (not enclosed by a fruit). CONIFERS CYCADS GINKGOS 19 Tracheophyte #3 video Angiosperms (flowering plants) – Adaptations: – vascular tissue – Flowers (reproductive structure) – Seeds develop within ovaries – Fruit- ripened ovary 19 Structure of a Flower Monocots VS Dicots Work with your face partner… Create two lists that describe the characteristics of monocots and dicots 19 Classes of Angiosperms 1 cotyledon DICOTS 2 cotyledons 19 Monocots and Dicots (classes of Angiosperms) lily Oak tree grass Cherry Tree Fig. 19-5 1. Which group of algae has been hypothesized to be the ancestor of plants? 2. Which group of plants evolved most recently? 3. What main adaptation separated the pteridophytes from bryophytes? 4. In which group of plants did seeds first appear?