Plant Kingdom Introduction

Transcription

1 Plant Kingdom Introduction

2 Remember Photosynthesis! Sun + 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2

3 Remember Respiration! C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O + ATP + heat

4 Plant Kingdom All Plants: Eukaryotic Multi-cellular Most contain chlorophyll in chloroplasts Use mitochondria Live on land and water Do not move from place to place

5 Plant Kingdom Origin and Evolution For most of the history of the Earth life existed in the ocean. Plants moved to land first Evolved from algae

6 Early Plants Oldest plant: Rhynia major, Silurian ~420 mya Simple, no seeds, no leaves Rely on water for reproduction Similar plants live today

7 Rhynia major

8 Plant Evolution

9 Conditions compared

10 Conditions compared In water: Lots of water (duh) Support Light limited Limited CO 2 and O 2 levels

11 Conditions compared On Land No support Water limited Lots of light Lots of CO 2 and O 2

12 Adaptations to land Problem: Support. In water density supports plant Land Solution: Cell walls made of cellulose, trees also have lignin for extra support

13 Adaptations to land Problem: Protection from drying out Land Solution: Cell walls and waxy cuticle that covers leaves and stems. Roots and special cells to carry water in Vascular plants

14 Classification: Seedless Plants Seedless Nonvascular: No vascular tissues, reproduce with spores. Need water for reproduction. Eg. mosses, liverworts. Seedless Vascular: Vascular tissues, reproduce with spores. Need water for reproduction. Eg.: ferns, horsetails, lycophyta.

15 Classification: Plants with Seeds Gymnosperms: Vascular. Reproduce with seeds, no flowers. Eg.: pine trees, gingko, firs, junipers. Angiosperms: Vascular. Reproduce with seeds, have flowers. Eg.: grass, rose, corn, daisy.

16 Evolution of Plants

17 Classification

18 Typical Land Plant

19 Vascular Flowering Plant

20 Vascular tissue Plants need to move materials through their bodies This is done in the vascular tissues Vascular tissues are tube-shaped cells 2 kinds of vascular tissue: Xylem Phloem

21 Xylem Dead cells Transport water and minerals from roots up to the shoot

22 Xylem Cells

23 Phloem Living cells Transport sugars down from leaves to the roots and across to other parts of the plant sap

24 Adaptations: Roots Plants use their roots to absorb water and anchor the plant Roots have small fungi called mycorrhizae that live next to them (myco = fungus, rhizae = root) Mycorrhizae are symbiotic fungi that help the plant absorb minerals and water

25 Mycorrhizae

26 Adaptations: Leaves Most photosynthesis takes place in the leaves, but sometimes the stem is important too Gas exchange happens through pores in the leaf called the stomata Stomata are surrounded by two cells called the guard cells When there is enough water in the plant the guard cells open up and let CO 2 in and O 2 out A waxy layer (not cells) called the cuticle helps keep water in the plant. It coats the leaves and stems

27 Leaf Diagram

28 Leaf structure Most light falls on the upper side of the leaf Most chloroplasts are located in the palisade layer in the upper part of the leaf Most gas exchange happens in the spongy layer on the lower side of the leaf Most stomata are located on the underside of the leaf

29 Cuticle sem photos

30 Leaf cross-section

31 Stomata

32 Leaf cross section

33 Water Loss: Transpiration Water moves out of cells by osmosis Water lost through stomata by osmosis is transpiration Plants minimize transpiration by closing the stomata Transpiration helps pull water through plant to the leaves where it is used in photosynthesis (remember water is polar!)

34 Trees and water

35 Support In water the density of the water supports the algae On land, plants had to adapt a support system Support is provided by the cell walls (cellulose) Plants also have a chemical called lignin that hardens the cell walls Lignin provides tremendous support

36 Lignin Support!