Plants CH 22 and 23 Honors Biology

Vocab Prep 22.1-22.2 (in textbook) Divide and conquer Alternation of Generations Sporophyte Gametophyte Greek Root Words: Phyta/Phyte Bryophyte Vascular Tissue Archegonium Antheridium Sporangium Tracheophyte Tracheid Xylem Phloem Seed Gymnosperm Angiosperm Pollination Ovule

Characteristics of Plants Kingdom Plantae Eukaryotes Contain cell walls (cellulose) Chlorophyll a and b Why do they need these? Autotrophs

Killer Plants? Parasites Use a haustorium (modified stem or root) to “steal” nutrients and water from host plant. Ex: Mistletoe! Venus Fly Trap?? Basically creates it’s own fertilizer

What do plants need? Sunlight Gas Exchange Water and Minerals Resource How do they get it? Sunlight Gas Exchange Water and Minerals

Plant Evolution Where did life begin? First plants in fossil record are similar to green algae How did plants evolve for life on land? First land plants were small and found only in damp areas Greatest challenge = how to get water Had to be resistant to drying out Needed to be able to reproduce without water

Alternation of Generations

Seedless Nonvascular Plants Green Algae Mostly aquatic Do not contain specialized tissues Uses both sexual and asexual reproduction Lack true vascular tissue

What is the benefit of having both? Zygote resistant to harsh conditions

Bryophytes (mosses) Can live on land Seedless Lack true vascular tissue so they are small Alternation of generations (gametophyte dominant) Needs water to reproduce

Vascular Plants (Tracheophytes) Xylem: tissue that carries water from roots to shoots Contain tracheids made of lignin and vessel elements Both made of dead cells Phloem: tissue that transports sugars from shoots to roots Sieve tube elements and companion cells Made of live cells Allows plants to be taller Alternation of Generations (Sporophyte dominant)

Seedless Vascular Plants Club moss, horse tail and ferns

Requires water for fertilization

Seed Plants Seed= plant embryo and food supply encased in protective covering Evolutionary significance? Type of Seed Plants Gymnosperms Cone contain seeds (naked) Angiosperms Flowers contain seeds (protected by ovary) We will discuss this when we get to Genetics

Plant Tissues 1. Dermal Tissue Protection Often covered by waxy cuticle May have Trichomes (fuzzy)

2. Vascular Tissue Support and transport Xylem and Phloem

Produces and stores sugars Contribute to physical support Contains: 3. Ground tissue Produces and stores sugars Contribute to physical support Contains: Parenchyma Cells: thin cell walls, found in leaves and contain chloroplasts Collenchyma Cells: thicker cell walls, celery Sclerenchyma: thickest cell walls, seed coats

4. Meristems Produces new cells Apical meristems: responsible for growth in length or roots and stems Floral meristems: responsible for growth of flowers

Organs of Seed Plants 1. Roots Function: Anchor and prevent soil erosion Work with bacteria a fungi to absorb water and nutrients Types 1. Taproots 2. Fibrous Root

2. Stems Function: Produce leaves, branches and flowers Support Transport Growth of Stems Primary: apical meristems add length through cell elongation

Secondary: increase in thickness Rare in monocots Vascular cambium gives rise to new layers of xylem and phloem so that stem becomes wider This secondary xylem is wood Bark: tissues found outside vascular cambium -includes: Pholem, cork cambium which produces cork (waterproofs)

Xylem near the center no longer conducts water and is called heartwood (dark color) Sapwood does conduct water (light color) How do you age a tree? Count the rings (analyzing data p. 678)

3. Leaves Consists of ground tissue called mesophyll Palisade mesophyll: absorbs light Spongy mesophyll: contains air spaces for gas exchange via the stomata Guard cells control the opening and closing

Transpiration