Chapter 23 Introduction to Plants 1

1. Autotrophs 2. Multicellular 3. Eukaryotes 4. Cell Wall is made out of Cellulose 2

1. Bryophytes-Mosses (Seedless, Non-Vascular) 2. Seedless vascular plants- Ferns 3. Gymnosperms- Evergreens (Pine Trees) 4. Angiosperms-Flowering plants 3

 Chemical Equation: ◦ CO 2 + H 2 O  C 6 H 12 O 6 + O 2  Word Equation: ◦ Carbon Dioxide + Water  Glucose + Oxygen Sunlight 4

 The common ancestor of ALL plants is thought to be Green Algae  In the early evolution of plants, they made the transition from aquatic to land environments 5

 Mycorrhizae is a mutualistic relationship between plants and fungi to help a plant absorb water from the soil.  This relationship helped plants transition to land. 6

 Almost all plants have a cuticle covering their leaves and stems to prevent water loss  The cuticle is waxy (lots of lipids) and holds water in  The cuticle is also clear to let sunlight in for photosynthesis 7

8

 An alternation between two distinct forms or generations that reproduce differently  One generation is haploid and reproduces sexually  The other generation is diploid and reproduces asexually 9

By definition, all plants alternate generations Gametophyte n=haploid Sporophyte 2n=diploid 10

Notice that the more advanced plants have a dominant Sporophyte and the less advanced plants have a more dominant Gametophyte 11

Multicellular diploid organism (2n) Unicellular haploid cells (n) meiosis Unicellular diploid zygote (2n) mitosis (spores) Multicellular haploid organism (n) mitosis Unicellular haploid gametes (n) fertilization sporophyte gametophyte mitosis 12

Bryophytes Green algae Seedless vascular plants Gymnosperms Angiosperms Evolution of specialized cells / tissue Evolution of cuticle 13

 Bryophytes  Example: Moss 14

15

 They are small and low to the ground because they do not have vascular tissue  Found only in damp, moist areas on land ◦ 1) Leaves must absorb water for photosynthesis ◦ 2) Sperm swims through water to reach egg in gametophyte 16

gametophyte sporophyte 17

Moss Life Cycle 18

Bryophytes Green algae Seedless vascular plants Gymnosperms Angiosperms Evolution of specialized cells / tissue Evolution of cuticle Evolution of vascular tissue 19

 Example: Ferns 20

21

 Vascular Tissue ◦ Set of tubes that transport materials around plant ◦ Allows plants to grow taller ◦ Water travels up through Xylem ◦ Sugar/Food travels throughout in Phloem 22

23

 Still must live in moist areas  Sporophyte grows successfully with vascular tissue  But sperm must still swim to egg in tiny gametophyte 24

25

26

Fern Life Cycle 27

Bryophytes Green algae Seedless vascular plants Gymnosperms Angiosperms Evolution of specialized cells / tissue Evolution of cuticle Evolution of vascular tissue Evolution of pollen grains / seeds 28

 Gymnosperms/Angiosperms  Example: Pine Trees or Flowers 29

 Examples: Spruce Tree, Fir Tree, Pine Tree 30

 Think cones (any conifer like pine trees) female ovary male pollen cone 31

tiny gametophyte inside cone sporophyte Sporophyte Dominates 32

 Release a lot, hope some pollinate  (Meanwhile, irritating everyone else)  Pollen is the male sperm in Gymnosperms and Angiosperms 33

 Seeds  Pollen Grains 34

 Tough coat protects newly fertilized embryo  Also contains supply of food (endosperm) to survive during dormancy period  A seed in a gymnosperm is inside the cone 35

36

 Plants try to disperse offspring far away so they have a higher chance of survival.  Dispersal of seeds prevents competition for water, nutrients, light, and living space. Seed Dispersal 37

38

 Dispersal by wind – wing-like structures, parachute-like structures 39

 Dispersal by animals – fruits have hooks that cling on animals fur, other fruits provide food for animals 40

 Seeds dispersal is completed by birds, small animals, wind, and water  The tough, fibrous outer covering of a coconut provides protection as well as a floatation device 41

 Hard covering around sperm, light weight allows travel by wind  Removes water requirement for fertilization 42

 At the very end when pollen lands on another plant of the same species  Pollen tube connects to ovary, sperm swim to egg 43

Bryophytes Green algae Seedless vascular plants Gymnosperms Angiosperms Evolution of specialized cells / tissue Evolution of cuticle Evolution of vascular tissue Evolution of pollen grains / seeds Evolution of flowers / fruits 44

 Think flowers  Most diverse plant group 45

 Flowers ◦ Adapted for pollination by animals ◦ Attract animals to help carry pollen to the next flower ◦ Color or scent attractors guide animals to obtain sugar from plant ◦ Some angiosperms still wind pollinate (grass) 46

47

48

49  Monocots include: grasses, corn, rice, oats, wheat, orchids, lilies and palms  Dicots include: shrubs, trees (except conifers) wild flowers and some garden flowers

50

51

52

53

 Monocot-pedals in groups of three or multiples of three  Dicots-pedals in groups of 4s or 5s 54

Sepals protect the flower bud from insect damage and dryness The color, scent, and nectar of flowers attracts insects, bats, and birds These animals help to transfer the pollen from the anthers of one flower to the stigma of other flowers- called pollination 55

tiny gametophyte inside bottom of flower rest of plant = sporophyte Sporophyte Dominates 56

The Pollen grains are transferred to the Stigma where the pollen grain produces a Pollen tube The pollen tube grows down the style into the ovary where it fuses its nuclei with the nuclei of the ovule The fertilized ovule becomes a seed and the ovary develops into the fruit of the plant 57

58

59

 Typically collects sugar to attract animals  Seeds survive animal digestive system, pooped out far away from parent (and with free fertilizer!)  Some are not eaten by animals, just help wind carry seed ◦ Example: dandelion 60

Bryophytes Green algae Seedless vascular plants Gymnosperms Angiosperms Evolution of specialized cells / tissue Evolution of cuticle Evolution of vascular tissue Evolution of pollen grains / seeds Evolution of flowers / fruits 61

 Plants can also reproduce asexually  Vegetative reproduction is faster than sexual reproduction.  Vegetative reproduction is where many plant parts can regrow to make a whole new organism when separated. ◦ Examples: Ivy or Potato 62

 A division of seed plants that have only one living species  The leaves of the plant are fan shaped  The ginkgo is the oldest tree in the world, once thought to be extinct  Ginkgo’s are the lone survivor of a "family that existed more than 200 million years ago" and kept company with the dinosaurs 63

64

 The male trees are preferred because female trees bear a fruit which, after dropping, emits a foul odor. The fruit is about the size of a cherry tomato  Roasted nuts from Ginkgo biloba trees have long been considered a delicacy in their native China.  Treatment for short-term memory loss is just one of many medicinal uses for the extract derived from the leaves of Ginkgo biloba trees. 65