Plants are believed to have evolved from ________________.
Freshwater green algae
Plants are most closely related to a group of green algae known as ___________.
Stonewarts, perhaps in genus Chara.
What are the 4 Evolutionary Events that allowed plants to adapt to land.
1. protecting the embryo
2. having vascular tissue for transporting water and organic nutrients
3. use seeds to disperse offspring
4. having flowers
*see page 414, Mader
Alternation of Generations
All plants have a life cycle that includes an alternation of generations. In this life cycle, two multicellular individuals alternate, each producing the other.
The two individuals are sporophyte - represents the diploid generation
gametophyte - represents the haploid generation
A _______ structure is more apt to survive genetic damage because two copies of each chromosomes allow recessive mutations to be masked.
a. diploid
b. haploid
diploid
All plants possess a ___________, a waxy covering on aerial plants that reduces desiccation.
cuticle
Xylem transports ___________.
a. water
b. glucose
water
Phloem transports _________.
a. water
b. glucose
glucose
_____________ developed as centers for photosynthesis.
A. true leaves
________________ developed to provide framework to support leaves
B. true stems
_____________ developed to obtain water and anchor the plant.
A. true roots
In the more primitive plant divisions, flagellated sperm require water to swim to the eggs.
a. true
b. false
true
In the more advanced divisions (Coniferophyta and Anthophyta), the sperm, packaged as ___________, are adapted for delivery by wind or animals.
Pollen
The most advanced plant division is the ______________.
Anthophyta
In the most advanced division, the Anthophyta, the gametophytes are protected inside an ____________.
ovary
The bryophytes consist of 3 groups of plants:
1.
2.
3.
1. mosses
2. liverworts
3. hornworts
In bryophytes, gametes are produced in protective structures called ___________.
Gametangia - on the surface of gametophytes
In bryophytes, the male gametangium is also called _______________.
Antheridium
In bryophytes, the _______________ produces flagellated sperm that swim through water to fertilize the eggs produced by the female gametangium, or archegonium.
antheridium
The female gametangium is called _________________.
Archegonium
Since bryophytes are primitive, they lack many specialized structures like?
true roots, true stems, true leaves
Because bryophytes lack specialized vascular tissue such as the xylem and phloem, they must remain small and water must be readily available for absorption through surface tissues and as a transport medium for sperm.
a. true
b. false
true
Bryophytes dominated generation is _____________.
haploid gametophyte generation
Phylum Lycophyta include what type of plants?
club mosses
spike mosses
quillworts
**known as herbaceous plants
The Phylum Pterophyta include which group of plants?
2. microspore mother cells divide by meiosis to produce four haploid cells, the microspores
3. Microspores mature into pollen grains
4. pollen grain further divides into 3 cells (in flowering plants), or 4 cells (in conifers).
5. One of these cells is a vegatative, or tube, cell that controls the growth of the pollen tube
6. Other cells become the sperm cells.
What does a pollen grain represent?
Represents the male gametophyte generation
Reproduction of seed plants, Megasporangium:
the megasporangium, called the nucellus produces many microspore mother cells
microspore mother cells divides by meiosis to produce 4 haploid cells
one of these cells survives to become the megaspore and represents the female gametophyte generation
the megaspore divides by mitosis to produce one egg (in flowering plants) or 2 eggs in conifers.
one to two layers of integuments surround the megasporangium.
integuments, nucellus, and megaspore daughter cells are collectively called the ovule.
an opening through the integuments for pollen access to the egg is called the micropyle.
What happens once the pollen grain contacts the megasporangium?
the tube cell directs growth of a pollen tube through the microphyle and toward the egg.
After fertilization by the sperm cells, the zygote divides to form an _____________.
Embryo - marks the beginning of the sporophyte generation
Integuments develop into the __________.
Seed coat
Conifers can also be called ________________.
Gymnosperms - means "naked seeds"
seeds produced in unprotected megaspores near the surface of the reproductive structure
________________ consist of flowering plants.
anthophyta or angiosperms
The ___________ is the female reproductive structure in flowering plants.
pistil
The pistil contains 3 parts:
1.
2.
3.
1. ovary - contains egg
2. style
3. stigma
The ____________ is the male reproductive structure.
stamen
The stamen contains 3 parts
1.
2.
3.
1. anther - contains pollen
2. stalk
3. filament
___________, function to attract pollinators.
petals, sometimes called sepals
The flower is a major evolutionary advancement for 3 reasons:
1. flower is a special adaption to attract pollinators, such as insects and birds.
2. ovules are protected inside an ovary
3. ovary develops into a fruit, which fosters the dispersal of seeds by wind, insects, etc.
Fertilization in angiosperms:
1. pollen lands on sticky stigma
2. pollen tube, an elongating cell that contains the vegetative nucleus (or tube nucleus) grows down the style toward the ovule
3. there are two sperm cells inside the pollen tube.
4. ovules within the ovary consist of megaspore mother cell surrounded by the nucellus and integuments.
5. the megaspore mother cell divides by meiosis to produce 4 haploid cells, the megaspores
6. One surviving megaspore divides 3x by mitosis to produce 8 nuclei.
7. 6 nuclei undergo cytokinesis and form plasma membranes
8. the result is an embryo sac
9. at the micropyle end of the embryo sac are 3 cells- one egg cells, and 2 synergids.
10. at the end opposite the micropyle are 3 antipodal cells
11. in the middle are two haploid nuclei, the polar nuclei
*12. when the pollen tube enters the embryo sac through the micropyle, one sperm cell fertilizes the egg, forming a diploid zygote.
13. the nucleus of the second sperm cell fuses with both polar nuclei, forming a triploid nucleus
14. triploid nucleus divides by mitosis to produce the endosperm, providing nourishment for subsequent development of embryo and seed
15. fertilization of the egg and the polar nuclei each by a separate sperm nucleus is called a double fertilization
Angiosperms are divided into two groups:
1. dicotyledons (dicots)
2. monocotyledons (monocots)
In angiosperms, _______________ are storage tissue that provides nutrition to the developing seedling.
cotyledons
Dicots
2 cotyledons
netted (a branching pattern) - leaf venation - pattern of veins in leaves
flower parts - in 4s, 5s, or multiple
vascular bundles - organized in a circle
root - taproot (a large single root)
Monocots
1 cotyledon
leaf venation - parallel
flower parts - in 3s or mutiples
vascular bundles - scattered
root - fibrous system (cluster of many fine roots)
Plant tissue have 3 distinct major groups:
ground tissue
dermal tissue
vascular tissue
In ground tissue, there are 3 basic cells found in their cell walls:
1. parenchyma cells
2. collenchyma cells
3. sclerenchyma cells
In ground tissue, ________________ are the most common components of ground tissue, have thin walls and serve various functions including storage, photosynthesis, and secretion.
parenchyma cells
In ground tissue, _______________ which have thick but flexible cell walls, serve mechanical support functions.
collenchyma cells
In ground tissue, _______________ with thicker walls than collenchyma, also provide mechanical support functions.
sclerenchyma
____________ tissue consists of epidermis cells that cover the outside of plant parts.
Dermal tissue :
guard cells that surround stomata
various specialized surface cells such as hair cells, stinging cells, glandular cells
epidermal cells secrete waxy protective substance, the cuticle.
Parenchyma
least specialized of the cell types
found in all organs of a plant
may contain chloroplasts and carry on photosynthesis
or may contain colorless plastids that store the products of photosynthesis
can divide and give rise to more specialized cells, such as when roots develop from stem cuttings placed in water
Collenchyma
similar to parenchyma except have thicker primary walls
give flexible support to immature regions of plant body
i.e. familiar strands in celery stalks are composed mostly of collenchyma
sclerenchyma
have thick secondary walls impregnated with lignin that makes the walls tough and hard
most sclerenchyma cells are non living
their main function is to support MATURE regions of a plant
two types of cells are found: fibers, sclereids.
_______________, which are epidermal cells with chloroplasts, surround the stomata.
guard cells
In leaves, the lower epidermis of eudicots and both surfaces of monocots contain specialized cells called _______________.
Guard cells
The walls of epidermal cells that are exposed to air are covered with __________.
cuticle - waxy
In older woody plants, the epidermis of the stem is replaced by a _________.
cork
Xylem contain two types of conducting cells:
Traceids
Vessel elements
*Both are hollow and nonliving
The conducting cells of phloem are _______________.
Sieve-tube members - arranged to form a continuous sieve tube
_______________ contain cytoplasm but no nuclei
a. pits
b. sieve-tube members
c. tracheids
sieve-tube members
*Each sieve-tube member has a companion cell, which DOES have a nucleus.
The two are connected by numerous plasmodesmata
In roots, the vascular tissue is located in the _______________.
Vascular cylinder
In stem, vascular tissue forms ______________.
Vascular bundles
In leaves, vascular tissue is found in ______________.
Leaf veins
Organization of roots:
The primary meristems are in the zone of _______________, which continuously provides cells to the zone of elongation.
Primary meristems
Tissues of Eudicot root
The _____________, which forms the outer layer of the root, consist of only a single layer of cells.
epidermis
Tissues of a Eudicot root:
_________ cells make up the cortex of the root.
Parenchyma
Tissues of a Eudicot Root
The ________ functions in food storage
cortex
Tissues of Eudicot Root:
In the zone of maturation, many_______________ cells have root hairs
epidermal
Tissues of Eudicot Root:
______________ regulates the entrance of minerals into the vascular cylinder.
Endodermis
Tissues of a Eudicot Root:
The endodermis contains a layer of impermeable lignin and suberin known as ______________.
Casparian strip
Tissues of Eudicot Root:
The _______________ prevents the passage of water and mineral ions between adjacent cell walls.
Casparian strip
The only entrance to the vascular cylinder is through the _________.
Endodermal cells
The first layer of cells within the vascular cylinder is the ______________.
Pericycle
The xylem appears ______________ in eudicots because several arms of tissue radiate from a common center.
star-shaped
In some plants, notably Eudicots, contain what type of root system?
Taproot -fleshy, stores food
In some plants, notably Monocots, what type of root system dominates?
Fibrous root system
When roots develop from organs of the shoot system instead of the root system, they are known as ___________________.
Adventitious roots
Peas, beans, and other legumes have _______________, where nitrogen-fixing bacteria live.
root nodules
Plants cannot extract _____________ from the air.
Nitrogen.
But bacteria within the root nodules can take up and reduce the atmospheric nitrogen.
*This means that the plant is no longer dependent upon a supply of nitrogen from the soil.
During primary growth, the ____________ at a shoot tip produces new cells that elongate and thereby increase the length of the stem.
shoot apical
The shoot apical meristem is protected within a ______________ where leaf primordia (immature leaves) envelope it.
terminal bud
The bulk of a leaf is ____________ tissue bordered by an upper and lower layer of epidermis.
mesophyll
Cohesion-Tension Model
***transpiration creates a tension that pulls water upward in xylem
The cohesion-tension model of xylem transport suggests a PASSIVE mechanism for xylem transport.
cohesion refers to the tendency of water molecules to cling together.
adhesion- refers to the ability of water to interact with the molecules making up the walls of the vessels in xylem.
***read page 468, Mader
When the sun is up, the stomata __________, carbon dioxide enters.
a. open
b. closed
open
When the stomata is __________, carbon dioxide cannot enter, and plants are unable to photosynthesize.
a. open
b. close
close
**Therefore, photosynthesis, requires an abundant supply of water so that stomata can remain open and allow carbon dioxide to enter.
Like animals, plants utilize a ___________________ pathway when they respond to a stimulus.
Reception-Transduction -response
______________ are growth responses toward or away from unidirectional stimuli.
Tropoisms
The ________________ of stems results in a bending toward light.
Positive phototropism
The ________________ of stems results in a bending away from the direction of gravity.
gravitropoism
Roots that bend toward the direction of gravity show _____________.
Positive gravitropoism
_____________ occurs when a plant part makes contact with an object, as when tendrils coil about a pole.
Thigmotropoism
Auxin is produced in the _______________.
shoot apical meristem
*found in young leaves and flowers, fruits.
________________ are growth promoting hormones that bring about elongation of the resulting cells.
Gibberellins
_____________ are a class of plant hormones that promote cell division.
cytokinins
_____________ is sometimes called the stress hormone because it initiates and maintains seed and bud dormancy and brings about the closure of stomata.
