Transcript Section II. 5 Characteristics of Plants

Section II.
5 Characteristics of Plants
II. 5 Characteristics of Plants
( See Page 12 in your textbook:)
1.
2.
3.
4.
Multicellular
Autotrophic
Cell walls of cellulose
Reproduction w/ Alternation of
generations
5. Protected embryos
Each of these characteristics is not itself unique to plants but together
distinguish plants from other organisms.
1. Multicellular
• Plant kingdom members are multicellularunicellular algae - grouped with protists.
• Plants have specialized tissues, organs &
structures
• Obviously, not all plants look the same.
They have different flowers, stems, and
even root structures.
2. Autotrophic
• “Makes its own food”
• Process =
photosynthesis
• Light is actually energy, electromagnetic energy.
• Photosynthesis actually uses only certain colors to make
photosynthesis happen. Plants mostly absorb red and blue
wavelengths.
• When you see a color, it is actually a color that the object
does NOT absorb. (This is why leaves are green)
More about Photosynthesis:
• Happens in the cell organelle chloroplast.
• Pigment chlorophyll captures the light from the
Sun.
• Process of photosynthesis is divided into two main
parts.
1. Light dependent reaction. This reaction happens
when the light energy is captured and pushed into a chemical
called ATP.
2. Calvin Cycle Then the ATP is used to make glucose
(Also called the light independent reaction)
3. Cellulose in Cell Walls
• Plant cells have 3
organelles not
found in animal &
other cells:
• Central vacuole
• Chloroplasts
• Cell wall of
cellulose
http://www.enchantedlearning.com/subjects/plants/cell/anatomy.GIF
4. Reproduction w/ Alternation of
generations
• All plants have a life cycle known as
alternation of generations.
• In alternation of generations, a haploid
gametophyte produces gametes.
Gametes unite and give rise to a
diploid sporophyte.
Quick Genetics Lesson/Review
• Haploid:
Means a cell having 1 copy of
chromosomes.
• Diploid: means a cell having 2 copies of a
chromosome.
• Chromosome:
The genetic information (DNA
molecule) in a eukaryotic cell nucleus
Chromosomes
• Organisms have 2 copies of chromosomes (DNA
molecules with genetic information)
• 1 copy from each parent.
• The Gamete has only one copy of the
chromosomes.
• Zygote- (the fertilized egg)- produced from
fusion of 2 gametes
Reproductive cells
• Gamete: a haploid reproductive cell
– like egg & sperm in animals
– spores in sore forming plants
– pollen & ovule in seed plants
• Spore:
a haploid reproductive cell that can develop
into an organism with out combining with another cell
• Pollen: a haploid reproductive cell that is the “male”
in seed plants
• Ovule:
The female reproductive cell in seed plantsmay or may not be haploid.
Cell Division & Reproduction
• Mitosis-In eukaryotic cells, a process of cell
division that forms 2 new nuclei, each with the
same # of chromosomes as the parent cell. (a
clone )
• Meiosis- In eukaryotic cell, a process of nuclear
division in which the # of chromosomes is
reduced to ½ of the original cell. This forms
gametes (the reproductive sex cells.)
Explaining Alternation of
Generations…
• For sexually reproducing multicellular
organisms such as plants and animals-
• Diploid cells divide by meiosis to
create haploid cells.
• Haploid cells then fuse to recreate
the diploid number and a new organism.
Plants are different than animals in
sexual reproduction since they have 2
generations involved.
• Gametophyte- produces gametes
• Sporophyte- produces spores
• And just to make it even more interesting- the
gametophyte & sporophytes are different
depending on the kind of plant
Quick explanation of the generations:
• In nonvascular plants (moss)- the sporophyte
grows on the gametophyte, which are male &
female plants.
• In Ferns (seedless vascular plants) - the
generations are 2 separate plant forms
• In seed plants- the gametophyte grows on the
sporophytes
Alternating Life Cycles
More explanation
We’ll look more closely at the generations in ch 20-23
• Mosses- the egg & sperm produced by the gametophytes
(male & female plants) fuse to produce a small
sporophyte that grows right on the female plant.
• Ferns- the gametophyte is a separate small plant, the
sporophyte is the frond plant.
• 2 kinds Seed plants- there are naked seeds (pine cones)
& fruit enclosed seeds (angiosperms)
In flowering seed plants angiosperms:
• 2 fertilization events take place:
– one sperm fertilizes the egg to form the
diploid zygote of the new individual,
– the other sperm fertilizes the polar nuclei to
form the triploid endosperm, a nutritive
tissue ( the FRUIT).
• Together with maternal sporophyte tissue,
these make up the seed.
5. Protected Embryo
• All plants have a protected multicellular embryo
within the female parent.
• Evolved as a an adaptation to life on landpreventing the embryo from drying out.
(Algae DO NOT have a protected embryo like plants)
*Reproducing by seeds & spores
Developed structures to keep gametes
moist:
• Spore- a reproductive cell (a gamete) that is
surrounded by a hard outer wall. Needs at least a
small amount of water to survive.
• Seed – an embryo surrounded by a protective coat.
Can reproduce in a dry environment.
Some seeds contain an
• Endosperm- a tissue in some seeds that provides
nourishment.
Spores
• Ferns are non-flowering plants with large leaves that
reproduce by spore formation.
• To date there are 10,400 known species of true ferns.
• NEED WATER TO REPRODUCE
www.nybg.org/bsci/herb/ferns.html
Reproduction without water
• Spores require water for fertilization.
• Seed development is considered an
evolutionary improvement…
• Plants with seeds
– have a greater reproductive success
– embryo is protected & nourished
inside the hard coat.
– Seeds can remain inactive when conditions
are unacceptable for growth (hot, cold, drought)
Seeds
A bean is the seed of a bean plant. When the seed germinates, or starts to grow,
small parts inside the seed grow into the root and stem. Most of the seed is used
for food by the young plant. When the plant grows green leaves it begins to make
its own food by photosynthesis.
More about seeds
• A seed is a small embryonic plant
enclosed in a covering called the seed coat,
usually with some stored food.
• It is the product of the ripened ovule of which
occurs after fertilization and some growth
within the mother plant.
• 2 kinds of plants make seeds:
• gymnosperms (meaning “naked seed”are cone bearing plants like pine, fir, ginko)
• angiosperms (flowering plants)
http://en.wikipedia.org/wiki/Seed
More differences between Plants
& Animals
Plant reproduction & growth
• Unlike animals:
• Almost all Plants can reproduce sexually or
asexually whereas most animals reproduce only
sexually.
• Animals have determinate growth- they reach full
size & stop but plants grow throughout their lives
which is “indeterminate growth”
PART III- Plant Diversity
After brief notes- you will do a
packet on each chapter 20-23
•
III.
Plant
Diversity
There are 4 basic kinds of plants:
1. Nonvascular (mosses without true stems,
roots or leaves)
2. Seedless vascular (basically ferns- make
spores, not seeds)
3. Naked seeds (cones- gymnosperms)
4. Fruit enclosed seeds (angiosperms)
Evolutionary Relationship
Between Plants and Green Algae
12 “Divisions or Phyla of Plants
• 3 phyla of nonvascular plants
– do not have true
vascular tissue
– no roots, stems, or leaves.
• 9 phyla of vascular plants
– have vascular tissue
– have true roots, stems, and leaves.
Nonvascular plants- chapter
20
Non vascular plants
• The three phyla of nonvascular plants
are collectively called Bryophytes.
(These plants do not have true roots, stems, or
leaves & are very small and are usually found in
moist areas.)
1. Phylum Bryophyta – mosses
2. Phylum Hepatophyta - liverworts.
3. Phylum Anthocerophyta-hornworts
Types of non vascular plants:
• Moss
•
•
Liverworts
Hornworts
http://www.perspective.com/nature/plantae/bryophytes.html
What is a Vascular Plant?
• Plants with specialized tissues to transport
water & dissolved substances like sugar to
parts of the plant.
• Xylem-
tube like tissue that carries water
& minerals from roots to stems & leaves
• Phloem- carries organic compounds like
carbohydrates (sugars) from leaves to other
plant parts.
• Vascular tissue also helps support plants.
There are 9 Phyla of Vascular
Plants
Some adaptive advantages over nonvascular plants:
• specialized conducting tissues (xylem & phloem)
• the ability to grow large and live in many
environments
• strong stems that allow them to grow tall and receive
more sunlight.
Seedless Vascular Plants –
chapter 21
There are 4 Seedless
vascular plants (make spores)
•
•
•
•
Phylum Psilophyta, whisk ferns
Phylum Lycophyta, club mosses
Phylum Sphenophyta, horse tails
Phylum Pteridophyta. ferns
Seedless Vascular Plants
club mosses
•whisk ferns
horse tails
•ferns
http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/
Seed Bearing Vascular Plants
• There are two main groups of seedbearing vascular plants, gymnosperms
and angiosperms.
–Gymnosperms are characterized by
naked seeds and no flowers.
–Angiosperms have flowers and
seeds enclosed by a fruit.
Gymnosperms- chapter 22
4 Phyla of Gymnosperms
• Phylum Cycadophyta (cycas)
• Phylum Ginkgophyta (ginko)
• Phylum Coniferophyta (conebearing plants)
• Phylum Gnetophyta
• Cycas revoluta
•
ginkgo
•
•
www.botany.hawaii.edu
botit.botany.wisc.edu/.../Coniferophyta.html
universe-review.ca/I10-68-ginkgo.jpg
pine
gnetecaea
Angiosperms - Chapter 23
Angiosperms
(makes fruit & flowers)
• 1 Phylum - Anthophyta
– Is the largest phylum of plants, includes over
240,000 species of flowering plants.
– Have a flower and fruit.
• Angiosperms have been successful for many
reasons, including the production of fruit that
protects seeds, quick germination, & efficient
vascular system.
Angiosperms-parts
Characteristics:
• Vascular tissues
• Flowers, fruit
• Divided into
• Monocots
• Dicots.
http://www.botany.uwc.ac.za/sci_ed/grade10/anatomy/
• MONOCOTS
• Embryo with single
cotyledon
• Flower parts in multiples
of three
• Major leaf veins parallel
• Stem vascular bundles
scattered
• Roots are adventitious
• Secondary growth absent
DICOTS
•Embryo with 2 cotyledons
•Flower parts in multiples of
four or five
•Major leaf veins reticulated
•Stem vascular bundles in
a ring
•Roots develop from radicle
•Secondary growth often
present
Moncot & Dicot species
http://hawaii.hawaii.edu/laurab/generalbotany/130syllabus.htm
Flowers
• Pistil
Parts of a flower
(female parts)
Stigma
Style
ovary
• Stamen
(male parts)
Anther
Filament
Not All Flowers Smell As Sweet As
A Rose
Some Flowers Smell Like A Rotting
Carcass to Attract Insects
• purplish-red and foul-smelling stench
of dragon arum (Dracunculus
vulgaris) attracts flies to the base of its
erect, flower-bearing spadix.
• Although it is colorful, this is probably
NOT the flower to give to that special
someone in a bouquet
http://waynesword.palomar.edu/ww0602.htm#incarcerate
The World's Largest And Stinkiest
Arum
• “Corpse flower"
(Amorphophallus titanum).
• Native tropical rain forests of
Sumatra, Indonesia, flowered at
the New York Botanical Garden in
1937.
• Grew over 8 feet tall emerged from
a huge vase-shaped, pleated spathe
over 4 feet tall and 12 feet wide.
• people have been known to pass
out from taking a whiff.
Carnivorous Plants
Carnivorous Plants
All are under the phylum Angiosperm
• Plants make their own food but a small number
of plants are parasitic
• They feed on & harm other plants or organisms,
such as insects.
• This may be an adaptation for plants that live in
harsh environments, or where competition is
great for nutrients & minerals -like in poor
soil conditions.
Match the parasitic plants:
• Venus fly trap
Strangler figs
• Dodder plant
Sundews
•
•
•
•
•
Dionaea muscipula, also known as
the
Venus
Flytrap
Probably the most well known of
the carnivorous plants.
Insects are lured into the mouth-like
leaves by nectar.
Once an insect enters the trap it
touches tiny hairs on the leaves.
This sends impulses through the
plant triggering the leaves to close.
Glands located in the leaves release
enzymes that digest the prey and
the nutrients are absorbed by the
leaves.
http://www.botany.org/Carnivorous_Plants/
How a Venus' flytrap EATS
• Traps formed by hinged, 2-lobed leaf blades fringed with
stiff hairs.
• When the leaf blade folds closed, it traps an insect within a
jail of interlocking hairs.
• Three bristle-like hairs near
the middle of the upper side of
the leaf blade are sensitive to
touch, cause blade to snap shut.
• Touching one hair will not
trigger the closing mechanism.
Only when one hair is touched
twice or two hairs are touched
in succession will the leaf blade
fold closed.
stuff:http://waynesword.palomar.edu/carnivor.htm
More on unusual, parasitic plants
• Dodder plant- fast growing stems -also called
witches hair
• Strangler figs- plant takes over a host tree, stealing
all of the light, water & nutrients
• Pitcher plants- jug like leaves, insects attracted to
nectar, slip in & die
• Sundews- stick hairs with droplets at ends that trap insects, then
hairs wrap & dissolve prey
Good links to go to:
http://waynesword.palomar.edu/carnivor.htm
http://waynesword.palomar.edu/plnov99.htm
Dodder Plants
• Parasitizes various wild
and cultivated plants.
• Troublesome for alfalfa,
clover, onion growers
because dodder seed is difficult to remove from the
desired seed crop and can be spread with infested
seed.
• Its water, minerals and carbohydrates are absorbed
from the host through haustoria that penetrate the
host's tissue.
• Has some chlorophyll in the buds, fruits and stems,
but the amount of food manufactured in this tissue is
of little significance to the survival of the plant
http://www.coopext.colostate.edu/TRA/dodder.html
Strangler Fig or Banyan trees
• "strangling" growth
• in tropical forest species
• adaptation to compete for light
• Epiphytes (an organism that
grows upon or attached to a living
plant)
• their seeds, often bird-dispersed,
germinate on top of other trees.
• The seedlings grow their roots
downward, vines upwards &
envelope the host tree.
• Original support tree sometimes dies,
leaving a "columnar tree", central
core empty, of the Strangler Fig.
Pitcher plants:
Darlingtonia californica
(California Pitcher plant or Cobra Lily)
Darlingtonia's translucent leaves confuse insects trying to escape,
Then it digests them…….YUM
Nepenthes pitcher plants
The trap contains
a syrupy fluid that
the plant
produces,
and is used to
drown the prey.
Sundews
Tentacles topped with sticky secretions
-1. a sticky sweet mucilage to attract & ensnare insects
-2. enzymes to digest prey
They absorb the resulting nutrient soup
http://en.wikipedia.org/wiki/Image:Drosera_anglica_ne2.jpg
Do packets on chapters 20,
21, 22, 23
Additional References:
• Many pictures & some text from
www.wikipedia.org
• http://www.life.uiuc.edu/govindjee/page2.html
• http://www.botany.com/index.16.htm
• http://photoscience.la.asu.edu/Photosyn/study.html