Pages 632 – 644 Focus on life cycles of Green Algae Division Chlorophyta
Algae - Autotrophic Protistia
Monobiontic life cycle only one stage can undergo mitosis
Chlamydomonas Life Cycle of unicellular monobiontic life cycle
Dibiontic life cycle both stages can undergo mitosis
May have two multicellular generations (diploid/haploid)
Both the diploid individual and haploid have similar appearance – isomorphic generations
Ulva Life Cycle of dibiontic life cycle both stages are similar in apppearance
Diploid and haploid individuals have different appearance – heteromophic generations
Diagrams of life cycles for diploid organisms
Gametic meiosis
Zygotic meiosis
Sporic meiosis
See Handouts from class.
Nonvascular Plants (primative): Mosses, Liverworts,
and Hornworts
Division Bryophyta: Mosses
Gametophyte conspicuous (compare to seed plants)
Lacking true vascular tissue
Some may have hydroids(water) and leptoids (photosynthates)
Rhizoids for anchorage
Stomata present
Antheridia/ Archegonia
Motile sperm, single egg (both formed by mitosis)
(compare to seed plants)
Sporophyte small, heterotrophic (compare to seed plants)
Stalk, capsule operculum, peristome teeth
Spore Mother Cell undergoes meiosis to form spores (all survive)
HOMOSPOROUS (compare to seed plants)
Protonemata (perennial)
Gametophytes monoecious and dioecious forms
See Handouts From Class.
Division Hepatophyta: Liverworts
Gametophyte conspicuous (thallose or leafy) (compare
to seed plants)
Lacking true vascular tissue
Lacking hydroids and leptoids
Rhizoids for anchorage
Archegoniophore are stalked Archegonium
Antheridiophore are stalked with Antheridia
Motile sperm, single egg (both formed by mitosis)
(compare to seed plants)
Sporophyte small, elater ejects spore
Foot, seta, sporangium
Spore Mother Cell undergoes meiosis to form spores (all survive)
HOMOSPOROUS (compare to seed plants)
Gametophyte Dioecious (compare to seed plants)
Gemmae Cups – Gemmae tissue are produced in cups.
Type of asexual reproduction.
See Handouts From Class.
Division: Anthocerotophyta - Hornworts
Gametophyte conspicuous (compare to seed plants)
Thallos rosette
Motile sperm, single egg (both formed by mitosis)
(compare to seed plants)
Sporophyte long - horns
Sporangium with foot embeded in gametophyte
Spore Mother Cell undergoes meiosis to form spores(all
survive)
HOMOSPOROUS (compare to seed plants)
Gametophyte Monoecious (compare to seed plants)
See Handouts From Class.
Vascular Plants Without Seeds
Early (fossil) vascular plants-
Rhynia Zosterophyllophytes
Rhizomes and upright stems
Lacking leaves and roots
Dichotomously branched stems
Sporangium borne on tips
Guard cells
Homosporous
Protostele Xylem (tracheids) in the center;
no pith
Division: Psilotophyta - Psilotum
Sporophythe conspicuous (compare to nonvascular plants)
Consists of dichotomous branching stems and rhizomes
No roots or leaves
Cortex vascular cylinder with no pith (protostele)
Sporangium are borne on ends of stem
Gametophyte inconspicuous (2mm) (compare
to nonvascular plants)
Heterotrophic with small amounts of vascular tissue
Motile sperm, single egg (both formed by mitosis)
Spore Mother Cell formed in sporangium undergo meiosis
to form spores (all survive)
HOMOSPOROUS
Gametophyte Monoecious (bisexual)
See Handouts From Class.
Division: Lycophyta - Lycopoda
(club moss)
Sporophythe conspicuous (compare to nonvascular
plants)
Consists stems with enations (precursor to leaves)
and rhizomes
Enations may also be called microphylls
Roots for anchorage and absorption
Cortex vascular cylinder with no pith (protostele)
Lacking sporangium; clusters of cones or strobili
which produce sporangia
Gametophyte inconspicuous (2mm)
Heterotrophic with no vascular tissue
Motile sperm, single egg (both formed by mitosis)
Spore Mother Cell formed in sporangium undergo meiosis
to form spores (all survive)
HOMOSPOROUS
Gametophyte Monoecious (bisexual)
See Handouts From Class.
Division: Arthrophyta - Equisetum
Sporophythe conspicuous
Consists stems with joints and rhizomes
At each joint are whorls of leaves (megaphylls)
Roots for anchorage and absorption
Cortex vascular cylinder with pith (siphonostele)
End of stem are strobili (sporangiophore with
sporangia)
Gametophyte inconspicuous, parenchyma tissue
with antheridia and archegonia
Heterotrophic with no vascular tissue
Motile sperm, single egg (both formed by mitosis)
Spore Mother Cell formed in sporangium undergo meiosis
to form spores (all survive)
HOMOSPOROUS
Gametophyte Monoecious or Dioecious
See Handouts From Class.
Division: Pteridophyta - Fern
Sporophythe conspicuous
Consists of rhizomes with fronds
Fronds contain true leaves (megaphylls)
Roots for anchorage and absorption
Cortex vascular cylinder with pith (siphonostele)
Sporangia are borne in Sori of the fronds
Gametophyte inconspicuous, heart shaped with
antheridia and archegonia
Autotrophic with no vascular tissue
Motile sperm, single egg (both formed by mitosis)
Spore Mother Cell formed in sporangium undergo meiosis
to form spores (all survive)
HOMOSPOROUS
Gametophyte Monoecious
Compare the following plants:
Moss Liverwort Psilotum Lycopodium Equisetum
Fern
Location of meiosis
Antheridum/ archgonium location
Sporangium location
Strobili present
Alternation of Generation
(gametophyte/sporophyte)
Heterosporous/homosporous
Results of meiosis
Pollen present
Embryo nutrition
Monoecious/Dioecious
Seeds present
Location of fertilization (syngamy)
Motile sperms
Compare these to the four seed plants you studied earlier:
Angiosperms Gymnosperms
Cycads Ginkgo.
EXTRA!!
Kingdom: Planta
Characteristics: Consists
of eukaryotic cells. Organisms are autotrophic (photosynthetic)
with tissue organization. Cell wall consists of cellulose.
Four Divisions:
(1) Bryophyta - Moss
(2) Pterophyta - Fern
(3) Gymnosperm - Pine
(4) Angiosperm - Flowering Plants
These four divisions are classified based on the ploidy of the conspicuous plant, dispersion of DNA (genes) by spores or seeds, seeds formed in fruit which aids in dispersal.
All plants demonstrate alternation of generation. During the life cycle of plants there are two separate multicellular forms of the plant. One multicellular body is haploid (1n) which is called the gametophyte generation and the second multicellular body is diploid (2n) which called the sporophyte generation. During the life cycle of the plant these two body forms alternate. This arrangement is similar to that of Ulva discussed in the protist section; however, the two generations are not morphologically similar and are referred to as heteromorphic.
The sporophyte part of the life cycle begins with the fertilization of an egg with a sperm forming a zygote. The sporophyte part of the life cycle ends when meiosis occurs forming haploid spores. These spores will divide by mitosis and form the haploid multicellular plant. Consequently the gametophyte part of the life cycle begins with spores after meiosis and ends with fertilization forming a diploid zygote.
Compare life cycles of these four divisions.
Moss: Study the life cycle of a typical moss plant in the text. Note the following:
The conspicuous plant form is haploid or the gametophyte generation.
Sporophyte generation is inconspicuous.
Spores are formed after meiosis which are air borne to disperse the
genetic material of the plant.
Sperm are formed by mitosis in antheridium.
Eggs are formed by mitosis in archegonium.
Sperm are motile (flagella present) and water is required for fertilization.
Moss is considered a plant with no true vascular tissue (xylem and
phloem).
Since they do not have vascular tissue these plants do not grow to
a large size.
No seeds, fruit, double fertilization, or endosperm
Life cycle: zygote grows into a small inconspicuous sporophyte (2N) with a stalk and a capsule, inside the capsule sporangium tissue release individual diploid cells called spore mother cells into a cavity, these spore mother cells divide by meiosis forming four haploid spores (end of sporophyte beginning of gametophyte), spores are released for wind dispersal which eventually land on top of the soil, spores divide by mitosis forming a large multicellular plant consisting of leaf thallus and primitive stem tissue, no roots present but filamentous rhizoids anchors the plant in the soil, on the mature gametophyte archegonia form containing a single egg which was formed by mitosis and antheridia form containing several sperm which were formed by mitosis, sperm swim to archegonium and combine with the egg - fertilization (end of gametophyte and beginning of sporophyte), back to top
Rhizoids are root like structures with no vascular tissue. Roots have vascular tissue. Rhizomes are underground stems with vascular tissue.
Fern: Study the life cycle of a typical fern plant in the text. Note the following:
The conspicuous plant form is diploid or the sporophyte generation.
(unlike moss)
Gametophyte generation is inconspicuous.
Spores are formed after meiosis which are air borne to disperse the
genetic material of the plant.
Sperm are formed by mitosis in antheridium.
Eggs are formed by mitosis in archegonium.
Sperm are motile (flagella present) and water is required for fertilization.
Fern contains true vascular tissue (xylem and phloem).
Since they have vascular tissue these plants grow to a larger
size.
No seeds, fruit, double fertilization, or endosperm
Life cycle: zygote grows into a large conspicuous sporophyte (2N) with a stem, rhizomes and roots, sori develop on leaves, sori contain many sporangia, inside the sporangia sporangium tissue release individual diploid cells called spore mother cells into a cavity, these spore mother cells divide by meiosis forming four haploid spores (end of sporophtye beginning of gametophyte), spores are released for wind dispersal which eventually land on top of the soil, spores divide by mitosis forming a small inconspicuous multicellular plant consisting of green heart shaped thallus with filamentous rhizoids which anchors the plant in the soil, on the mature gametophyte archegonia form containing a single egg which was formed by mitosis and antheridia form containing several sperm which were formed by mitosis, sperm swim to archegonium and combine with the egg - fertilization (end of gametophyte and beginning of sporophyte), back to top
Rhizoids are root like structures with no vascular tissue. Roots have vascular tissue. Rhizomes are underground stems with vascular tissue.
Pines: Study the life cycle of a typical pine tree in the text. Note the following:
The conspicuous plant form is diploid
or the sporophyte generation.
Gametophyte generation is inconspicuous
inside of developing pine cones.
Two types of spores are formed male spores
from microspore mother cells and female spores from
megaspore mother cells.
Spores (megaspores and microspores) are formed
after meiosis which are not air borne to disperse the
genetic material of the plant. The megaspore
mother cell forms four megaspores by meiosis but only one
survives, the surviving megaspore divides
by mitosis forming a multicellular gametophyte containing an
egg inside an ovule of the female cone. The
microspore mother cell forms four microspores by meiosis
and all four survive. Each microspore
divides by mitosis forming a multicellular gametophyte called a
pollen grain. A sperm (nonflagellated)
will form inside the pollen grain. These pollen grains are borne
inside of a male cone and mature pollen grains
are male gametophytes.
Sperm are formed by mitosis inside the pollen
grain.
Eggs are formed by mitosis inside the female
gametophyte.
Sperm are nonmotile; however the pollen grains
are wind borne..
Pine have well developed vascular tissue (xylem
and phloem).
After fertilization the ovule surrounding
the female gametophyte forms a seed. Seeds contains the young
embryo. Seed protects and nourishes the young
growing embryo.
Seeds present. No fruit, double
fertilization, or endosperm
Life cycle: zygote grows into an embryo which is encased in a seed, the seed germinates and grows into the large conspicuous sporophyte (2N) with true vascular tissue, the mature saprophyte produces male and female cones, the female cone forms sporangium tissue with an egg sac, the sporangium tissue release individual diploid cells called megaspore mother cells into the egg sac, these megaspore mother cells divide by meiosis forming four haploid megaspores, three of these megaspores die and only one survives (end of sporophyte beginning of female gametophyte), the surviving megaspore divides by mitosis into the multicellular female gametophyte which contains a single egg in an egg sac, the male cone forms sporangium tissue with a pollen sac, the sporangium tissue release individual diploid cells called microspore mother cells into the pollen sac, these microspore mother cells divide by meiosis forming four haploid microspores, (end of sporophyte beginning of male gametophyte), each of these microscopes divide by mitosis and forms a pollen grain with a single sperm, pollen is released into the air (pollination) where it moves to a female cone, pollen tube grows and the sperm moves through the tube to fertilize an egg inside of an ovule (end of gametophyte and beginning of sporophyte), back to top
Sporophyte forms two types of gametophytes - male or female.
Flowering Plants: Study the life cycle of a typical flowering plant in the text. Note the following:
The conspicuous plant form is diploid or the sporophyte generation.
Gametophyte generation is inconspicuous inside of developing
flowers.
Two types of spores are formed male spores from microspore mother cells
and female spores from megaspore mother cells.
Spores (megaspores and microscopes) are formed after meiosis which
are not air borne to disperse the genetic material of the plant. The megaspore
mother cell forms four megaspores by meiosis but only one survives, the
surviving megaspore divides by mitosis forming a multicellular
gametophyte containing an egg inside an ovule located in an ovary
of a flower. The microspore mother cell forms four microscopes by
meiosis and all four survive. Each microspore divides by mitosis
forming a multicellular gametophyte called a pollen grain.
A sperm (nonflagellated) will form inside the pollen grain.
These pollen grains are borne inside the anther of a flower and mature
pollen grains are male gametophytes.
Sperm are formed by mitosis inside the pollen grain.
Eggs are formed by mitosis inside the female gametophyte.
Sperm are nonmotile; however the pollen grains are wind borne..
Flowering Plants have well developed vascular tissue (xylem and phloem).
Flowering plants have double fertilization. Two sperms form in a pollen
grain, one fertilizes the egg to form a zygote and the other combines with
two polar nuclei to form an endosperm nuclei (3N).
After fertilization the ovule surrounding the female gametophyte forms
a seed. Seeds contains the young embryo (cotyledon, epicotyl and hypocotyl)
and endosperm. Seed protects and nourishes the young growing embryo.
Ovules are formed inside an ovary of the flower. The ovary develops
into a fruit which is use to aid in seed dispersal.
Seeds, fruit, double fertilization, and endosperm present.
Life cycle: zygote grows into an embryo which is encased in a seed, the seed consists of embryo and endosperm, the seed germinates and grows into the large conspicuous sporophyte (2N) with true vascular tissue, the mature saprophyte produces male and female flower parts, the female flower part (ovary with ovules) forms sporangium tissue with an egg sac, the sporangium tissue release individual diploid cells called megaspore mother cells into the egg sac, these megaspore mother cells divide by meiosis forming four haploid megaspores, three of these megaspores die and only one survives (end of sporophyte beginning of female gametophyte), the surviving megaspore divides by mitosis into the multicellular female gametophyte which contains a single egg in an egg sac and polar nuclei, the male flower part (anther) forms sporangium tissue with a pollen sac, the sporangium tissue release individual diploid cells called microspore mother cells into the pollen sac, these microspore mother cells divide by meiosis forming four haploid microscopes, (end of sporophyte beginning of male gametophyte), each of these microscopes divide by mitosis and forms a pollen grain with a single sperm, pollen is released into the air (pollination) where it moves to a female flower part, pollen tube grows and two sperm moves through the tube to fertilize an egg inside of an ovule and two polar nuclei forming an endosperm nucleus (end of gametophyte and beginning of sporophyte), back to top
Sporophyte forms two types of gametophytes - male or female.
Comparison of Plant Life Cycles
Moss
Fern
Pine
Flowering Plants
sporophyte sporophyte sporophyte sporophyte
zygote
zygote
zygote
zygote
(2n)
(2n)
(2n)
(2n)
mitosis forms
mitosis forms
mitosis forms
mitosis forms
mature sporophyte
mature sporophyte
mature sporophyte mature sporophyte
sporangium
sporangium
male and female male
and female
mitosis forms
mitosis forms
cones with
flower parts with
spore mother cell
spore mother cell
sporangium
sporangium
(2n)
(2n)
male cones
male flower part
microspore mother cell microspore mother cell
female cones
female flower part
spore mother cell
spore mother cell megaspore mother cell
megaspore mother cell
meiosis forms four
meiosis forms four
spores (1n)
Spores (1n)
meiosis forms megaspores meiosis forms mega-
beginning of gametophyte
or microspores
spores or microspores
beginning of gametophyte
beginning of gametophyte
spores
spores
beginning of gametophyte
mitosis forms
mitosis forms
microspores or
microspores or
mature gametophyte mature gametophyte
megaspores
megaspores
antheridium with antheridium-sperm
microspores form
microspores form
sperm archegonium archegonium - egg
pollen with sperm
pollen with sperm
with egg develop by on gametophyte
mitosis on gametophyte
megaspores form
megaspore form
ovule sac with egg
ovule sac with
fertilization
fertilization
egg and polar nuclei
fertilization
beginning of sporophyte
zygote
double fertilization
beginning of sporophyte
zygote, endosperm
top
beginning of sporophyte
beginning of sporophyte
top
seed
seed and fruit
top
top
Plant Diversity Worksheet
Choose all correct answers from the right that refer to the statements
to the left.
a) Bryophyta-moss
b) Gymnosperms “coniferophyta”-pine
c) Pterophyta-fern
d)Angiosperms “anthophyta”-oak
Exhibits double fertilization
Sporophyte is dominant generation
Has autotrophic sporophyte
Has autotrophic gametophyte
Has heterotrophic sporophyte
Produces seeds
Autotrophic dominant plant
Contains vascular tissue
Forms endosperm during development
Exhibits alternation of generation
Gametophyte is dominant generation
Includes angiosperms
Includes gymnosperms
Includes conifers
Includes monocots
Indicate the type of cell division forming the following cell types.
a) mitosis
Megaspore
b) meiosis
spores of moss
egg cell of fern
microspore of pine
leaf cell
rhizome cell of fern
egg cell of moss
megaspore mother cell of oak
Indicate if the following are haploid, diploid or triploid
antheridium of moss
leafy thallus of moss
spore of fern
microspore mother cell
pollen cell of pine
frond of fern formed by crossing these two individuals
gametophyte of pine located in male cone
archegonium of fern
embryo of pine formed by crossing these two individuals
endosperm of oak
megaspore of oak
fruit of oak
spore of fern from the sporangium developing on the frond of a cross
between these two individuals
If in the question above the male sporophyte has the genotype of (aa)
and is crossed with a female sporophyte (Aa) list the genotype of the structures
listed.
Genetics and Plant Development
Behavioral Objective: given the genotype of a staminate flower and a carpellate flower determine the genotypes of all flower parts during flower development and developing seed and fruit parts.
1. Give the possible genotypes of the plant parts listed below
in a carpellate (female) flower (Aa) is
pollinated by a staminate (male) flower
(aa).
a. microspore
b. sperm nucleus
c. megaspore
d. zygote
e. synergid
f. polar nuclei
g. endosperm cells
h. cells of stigma
i. cells of integument
j. megaspore mother cell
k. cells of cotyledon
l. cells of ovary
m. cells of seed coat
n. cells of fruit
o. tube nucleus
p. microspore mother cell
2. Indicate the type of cell division which forms the following cells. (Mitosis and Meiosis)
a. microspore
b. megaspore mother cell
c. vessel element
d. megaspore
e. generative cell
f. tube cell
g. sperm cell
h. egg cell
3. Describe the following cell types as (haploid, diploid or triploid)
a. parenchyma
b. polar nuclei
c. microspore
d. megaspore mother cell
e. endosperm
f. sieve tube cell
g. egg
h. synergid
i. anitpodals
j. cotyledon cells
k. zygote
l. generative nucleus