Download Types of Plants Notes - Teacher Copy

PLANT NOTES – TYPES OF PLANTS
I.
Overview of the Plant Kingdom
A. What is a plant?
i
Multicellular
ii
Eukaryotic
iii Autotroph
iv Cell walls made of cellulose
v
Carries out photosynthesis
vi Stores energy as starch
B. Plant kingdom is divided into four groups based
on:
i
Water-conducting tissues
ii
Seeds
iii Flowers - 90% of all plants; 235,000 species.
C. Adaptations to Live on Land
i
Prevent Water Loss
-
waxy cuticle: thick layer for protection
-
stomata: open during the day, closed at night;
regulated by guard cells
ii
Leaves are specialized for photosynthesis
-
shaped to trap light energy
-
gas exchange occurs here
iii Specialized roots for absorption of water and minerals
iv Specialized stems for transporting minerals
v
Reproduction on land needs to occur with little or no water
-
some plants produce spores
-
others produce seeds
D. Alternation of Generations
i
Life cycle pattern where haploid
individual alternates with diploid
individual
ii
The diploid (2N) phase is called the
sporophyte, or spore-producing plant.
iii The haploid (N) phase is called the
gametophyte, or gamete-producing
plant.
II. Bryophytes
A. Non vascular plants ex: mosses, liverworts and their relatives.
B. Depend on water for reproduction
i
The sperm swims to reach the egg
C. Absorb water by osmosis only a few centimeters above ground
(causes them to be small)
D. Reproduce asexually
E. Types of Bryophytes
i
Mosses (Phylum Bryophyta)
-
Most common bryophyte
-
Found in areas with abundant water (bogs, swamps, near
streams, rain forests)
-
Grow in soil with few nutrients
-
Appearance can vary from miniature evergreen trees to small, filamentous plants that form a
threadlike green carpet.
ii
Liverworts (Hepaticophyta)
-
Some species look like the shape of the liver.
iii Hornworts (Anthocerophyta)
-
Also found in year-round damp soil.
F. Bryophyte Life Cycle
i
Method of reproduction = alternation of
generations.
ii
Dependence on water
-
Bryophyte sperm swim through water or dew to egg.
-
Raindrops can splash sperm from one plant to another.
G. Uses of Mosses
i
Dried mosses act as natural sponge for absorbing water.
ii
Peat moss is dead moss which is cut from the ground and burned as fuel.
iii Gardeners use peat moss to improve water retention in the soil.
III. Seedless Vascular Plants
A. Evolved from short to tall
i
About 420 million years ago, plants ranging in size from 1 meter up to small trees joined the mosslike plants.
B. Fossil evidence showed that these taller plants had vascular tissue to conduct water and nutrients
throughout the plant.
C. Vascular Tissue
i
New types of cells called tracheids that conduct water.
-
Tracheids make up the transport system known as
xylem which carries water from roots to other parts
of a plant.
-
Tracheids are hollow with thick cell walls that resist
pressure.
-
Connected from end to end, like a series of drinking
straws, are better at moving water than diffusion.
ii
The second vascular transport system is phloem.
-
Transports solutions of nutrients and carbohydrates
made from photosynthesis from the leaves down the plant.
iii Both xylem and phloem move fluids (water or nutrients) against the flow of gravity.
D. Overview
i
This group includes club mosses, horsetails, ferns.
ii
Most numerous phylum is the ferns.
iii Vascular system has true roots, leaves, stems.
iv Still requires water for reproduction for sperm to swim to egg.
v
Ferns
-
Have strong roots, underground stems called rhizomes,
and large leaves called fronds.
-
Require little light to grow and are abundant in wet
areas around the world under forest trees.
-
Grow as tall as small trees in tropical forests.
-
Fern sporophytes develop haploid spores on the
underside of their fronds in structures called sporangia.
-
Sporangia are grouped into clusters called sori.
IV. Vascular Seed Plants
A. Ability to form seeds allows these plants to be most dominant.
B. Divided into two groups:
i
Gymnosperms
-
cone-bearing plants
-
seeds on surfaces of cones.
-
includes conifers (pines, spruces), cycads, ginkgoes, and gnetophytes
-
Pollen grain contains gametophyte and sperm
-
Carried to female cone by wind, water, insects (pollination)
ii
-
Pollen grows tube to join egg (fertilization) forming seed
-
Ecology of conifers
*
Adapted to survive in dry conditions.
*
Conifers developed leaves that were long and thin to reduce water lost from evaporation.
*
Thick waxy layer on leaves also use to conserve water.
Angiosperms
-
Also known as flowering plants.
-
First appearance around 135 million years
-
Most recent plant
-
Method of reproduction involves flowers and fruit development.
-
Seeds are located in protective tissue
-
Includes grasses, flowering trees and shrubs.
-
Largest group
-
Reproduction free from water
C. Advantages of Seeds
i
Food supply for growing plant
ii
Protection by seed coat
iii Provides less competition with “parents”
iv Water not needed for fertilization
D. Flowers
i
Evolutionary advantage because they attract animals, which then transport pollen from flower to
flower.
ii
Contain ovaries, which surround and protect the seeds.
iii After pollination, the ovary develops into a fruit.
-
Wall of tissue that surrounds a seed.
-
Protects the seed and aids in its dispersal.
E. Two Classes of Angiosperms
i
ii
Monocots
-
One seed leaf (cotyledon) in embryo
-
Includes grasses, orchids, lilies, palms
-
Parallel veins in leaves
-
Flower parts in multiples of three
Dicots
-
Two cotyledons in embryo
-
Most flowering plants are dicots
-
Leaves with netted veins
-
Flower parts in multiples of four or five