Transcript What is a Plant? - St. Clair Schools

Introduction to Plants
Chapter 12
12.1 What is a Plant?
•Trees, grass, ferns, mosses, cactuses, water
lilies
•Can live on land, in or near water
•Many celled; made up of eukaryotic (have a
nucleus) cells
•Photosynthesize (producer = make food like
glucose & oxygen from carbon dioxide &
water)
•Have chlorophyll (green pigment that captures
energy from sunlight)
What is a Plant?
•Chlorophyll found in chloroplasts
•Have cuticle or waxy layer that coats plant
leaves & stems to keep them from drying
out
•Cell walls to provide protection & support (help
them stay upright)
•Cell wall made up of cellulose (organic compound
w/long chains of sugar molecules)
What is a Plant?
•Roots to hold them in the ground
•Roots & stems carry water, nutrients, remove
waste, & provide support
•Reproduction – 2 stages
1. sporophyte stage = plants make spores
2. gametophyte stage = new plant grows
from a spore (eggs & sperm produced &
join)
Plant Classification
Nonvascular
•Moss, liverwort
•No vascular tissue (xylem & phloem) to move
materials
•Diffusion moves material from one part of
plant to another
•Can absorb water through their cell walls
Plant Classification
Vascular
•Plants that have vascular tissue (known as xylem &
phloem)
•Vascular Tissue = long tube-like cells that carry
water & nutrients throughout the plant
•Divided into 3 groups
-Seedless like ferns, horsetail, & club
moss
-Nonflowering Seed plants called
gymnosperms
(like pine tree)
-Flowering Seed plants called angiosperms
(like apple tree)
Origin of Plants
•Green algae & plants share common
ancestor
•Lots of similarities like chlorophyll,
cell walls, photosynthesize, store
energy as starch, both have 2 stage
life cycle
12.3 Seed Plants
Characteristics of Seed Plants:
•Produce seeds
•Seeds nourish & protect young sporophytes
(plants)
•Gametophytes form within reproductive
structures of sporophyte
•Sperm need water to swim to the egg
•Sperm form inside pollen
Structure of Seeds
•Seed coat = surrounds & protects young
plant
•Cotyledons = stored food
•Sporophyte = young plant made up of
plumule (future leaves) & radicle (future
root)
Gymnosperms
•Vascular plants
•Produce seeds on scales of female cones
•Means naked seed (seeds not surrounded by a
fruit)
•No flowers or fruit
•Leaves mostly needlelike or scalelike
•Evergreen plants that keep leaves year round
Gymnosperms
•Most familiar is conifers (or cone-bearing):
pines, firs, spruces, cedars, junipers,
ginkgos
•Wood used for building, paper.
•Contain resin (sticky fluid made by tree) which
used in paint, soap, ink, some medicines
Gymnosperms
•Life cycle = male gametophyte found in pollen
(pollen contain sperm) & female
gametophyte make eggs; fertilized egg
develops into young sporophyte
•Pollination – transfer of pollen from male cones
to female cones usually by wind (both
male & female cones can be on same
tree)
Angiosperms
•Vascular plant
•Fruit surrounds & protects seeds
•You eat part of angiosperm
•Produce flowers AND fruit
Angiosperms
•Flowers help angiosperms reproduce (insects
carry pollen from flower to flower)
•Some seeds carried by wind or eaten by animal
then disposed of in feces
•Uses: crops like wheat, rice, & corn, food for
animals, produce tons of oxygen,
clothing, rubber, oils, perfumes, building
materials
•Two types: monocot & dicot
Monocots
•Mono means one
•Have one seed leaf or cotyledon inside their
seeds
•Flower parts in threes
•Vascular bundles (xylem & phloem) are
scattered randomly
•Leaves have parallel veins
•Examples: corn, rice, wheat, oats
Dicots
•Di means two
•Have two seed leaves or cotyledons inside their
seeds
•Flower parts in fours or fives
•Vascular bundles (xylem & phloem) form a ring
•Leaves have netlike or branching veins
•Examples: maples, lettuce, beans, oranges,
watermelons
Structure of Seed
Plants
12.4
Vascular Tissue
•Found in root & shoot systems
•Made up of xylem, phloem, & cambium
•Xylem transport water & minerals up from
roots throughout plant
•Phloem transport food from leaves & stems
to other parts of the plant
•Cambium found between xylem & phloem
and makes NEW xylem & phloem cells
Roots
•Supply plants w/water & minerals by
absorbing them from soil
•Hold plants in soil
•Store food made during photosynthesis
•Eat some roots (ex. carrots, beets)
Roots
•Roots have an epidermis (covers outer
surface), root hairs (increase surface
area), root cap (protects root tip)
•Roots grow longer at their tips
Roots
•Kinds of root systems:
Fibrous (several roots that
spread out from base of
plant’s stem, roots same
size - monocots)
Taproot (large main root
w/smaller roots branching
off, grows downward –
dicots & conifers are
examples)
Stems
•Tree trunks are really stems
•Supports plant body like leaves & flowers
•Carries water & minerals (xylem) from
roots to leaves and food (phloem)
back down to roots
•Some stems can store food or water
Stem
Stems
•Stems either herbaceous (soft, thin,
flexible stems) or woody ( hard, rigid
stems)
•Flower & crops are herbaceous while trees
& shrubs are woody
Stems
•Growth ring = ring of dark cells surrounded
by ring of light cells (equals one
growing season)
Leaves
•Vary in size but main job is to make food
for the plant (photosynthesis)
•Chloroplasts capture energy from sunlight
to make food (glucose)
•Cuticle (waxy layer on stems & leaves which
keeps plants from drying out or
wilting)
•Epidermis (upper & lower) single layer of
cells
Leaves
•Stomata (tiny openings in epidermis) allow
carbon dioxide to enter leaf & oxygen
to leave
•Stomata surrounded by guard cells which open
& close stomata
•Palisade layer (look like long pillars) contain
chloroplasts & most of food made here
•Spongy layer (circular) loosely arranged cells,
many air spaces which contain xylem &
phloem.
Flowers
•Flowers are reproductive organs
•Shape, size & color of flowers tells lots about
a plant’s life
•Brightly colored & fragrant flowers rely on
animals for pollination
•Plants w/o bright flowers rely on wind for
pollination
Flowers
•Flower Parts:
Colored parts are the petals (broad, flat,
leaflike)
Sepals modified leaves outside the petals;
protect the bud
Flowers
•Male Parts:
organ
Stamen is the male reproductive
Made up of:
1. a filament (long stalk)
2. anther (at the top of the stalk)
pollen stored, sperm made here
Flowers
• Flower Parts:
Pistil is the female reproductive organ
Made up of:
1. a stigma (sticky part on top to
catch pollen)
2. style (long, slender tube)
3. ovary (rounded base of the
pistil) ovules formed, eggs
made here
Flower Anatomy