Biology II Exam 2 -Botany

In plants with a haploid dominant life cycle, a haploid stage called a _______ is the thing you see as the plant itself

In plants with a haploid dominant life cycle, a haploid stage called a _______ is the thing you see as the plant itself

gametophyte

In plants, the vascular tissue that conducts sugars from the leaves is:

phloem

The most likely direct ancestor of modern land plants is:

a) Chara

b) cyanobacteria

c) green algae

d) moss

e) chloroplast

a) Chara

All types of plant cells have cell walls made of:

a) cellulose

b) lignin

c) chitin

d) peptidoglycan

e) mycelium

a) cellulose

A plant that has a diploid chromosome number that produces gametes via meiosis is called a/an:

a) sporophyte

b) gametophyte

c) angiosperm

d) gymnosperm

e) angiophyte

a) sporophyte

Which of the following is an example of a plant that has a haploid dominant life cycle?

a) moss

b) fern

c) pine tree

d) maple tree

e) lily

a) moss

True or False? Homosporous plants produce a single type of spore that germinate into bisexual gametophytes.

True

True or False? Seedless Vascular plants have a haploid dominant life cycle.

False

True or False? Mosses and liverworts do not have true leaves, roots, or stems.

False

True or False? Some plants spend approximately equal amounts of time in the haploid and diploid phases of their life cycles.

False

The cells in xylem have cell walls made of

lignin

Aside from the presence of flowers, name a characteristic of angiosperm plants

• Evolved approx. 130MYA

• Gametophytes are reduced and dependent on the sporophyte

• Diploid Dominant Lifecycle

Name the male reproductive organs of a flower

Stamen (Includes anther and filament)

Which group of plants is the most numerous and diverse?

a) bryophytes

b) seedless vascular plants

c) Gymnosperms

d) angiosperms

d) angiosperms

The seed is a protective casing that contains:

a) the gametophyte

b) endosperm (food)

c) the embryo

d) all of these

e) b and c only

e) b and c only

What kind of fruit develops from an ovary that contains a single seed?

a) pome

b) Drupe

c) Berry

d) Pepo

e) Hesperidium

b) Drupe

Angiosperms have which of the following life cycles?

a) haploid dominant

b) alternation of generations

c) diploid dominant

c) diploid dominant

True or False? Angiosperms are heterosporous.

True

True or False? Angiosperm flowers can only. be pollinated by physical forces, like wind and water.

False

True or False? Angiosperm ovules have to be fertilized by two sperm.

True

True or False? Some angiosperms attract pollinators by smelling like rotting meat.

True

What is the term for a dry fruit that opens when it is mature?

dry dehiscent

Characteristics of Bryophytes (Lab Chart)

• No vascular tissue

• non-vascular Land plants

• No true stems or rhizomes

• No true roots

• No true leaves (microphylls or megaphylls)

• Sperm must swim in water to reach egg

• No pollen

• No seeds

• No flowers or fruits

Characteristics of Lycophytes

• Vascular Tissue Present

• Seedless Vascular land plants

• True stems and rhizomes

• True roots

• True leaves (microphylls or megaphylls)

• Sperm must swim in water to reach egg

• No pollen

• No seeds

• No flowers or fruits

Characteristics of Horsetails and Ferms

• Vascular Tissue Present

• Seedless Vascular land Plants

• True stems or rhizomes

• True roots

• True leaves (microphylls or megaphylls)

• Sperm must swim in water to reach egg

• No pollen

• No seeds

• No flowers or fruits

Characteristics of Gymnosperms (Cycads, Conifers, Ginkgo Gnetophytes)

• Vascular tissue present

• Seeded Vascular Land Plants

• True stems or rhizomes

• True roots

• True leaves (microphylls and megaphylls)

• Sperm DO NOT need to swim in water to reach egg

• Pollen

• Seeds

• No flowers or fruits

Characteristics of Angiosperms

• Vascular Tissue Present

• Seeded Vascular Land Plants

• True stems or rhizomes

• True roots

• True leaves (microphylls and megaphylls)

• Sperm DO NOT need to swim in water to reach egg

• Pollen

• Seeds

• Flowers and Fruits

Early Cyanobacteria

• First photosynthesizers were cyanobacteria which lead to accumulation of oxygen in the atmosphere

  • Cyanobacteria becomes chloroplast via endosymbiosis (similar to modern glaucophytes) approx 1.25 BYA

Glaucophytes

• ancestral member of Kingdom Plante

  • primary endosymbiotic origin of the chloroplast was established in these

    • main characteristic shared by all plants

Red Algae

• Ancestral member of Kingdom Plante

• Are large multicellular seaweeds

• use 2 pigments phycoerythrin (red) and chlorophyll (green) for photosynthesis

• Example: Porphyra

Green Algae

• Include unicellular and multicellular species

• Non-plant members of Kingdom Plante

• Important group are the charophytes (Chara)

Charophytes (Chara)

• Can also be known as stoneworts, gets that name due to calcium carbonate precipitates onto its surface

• The direct ancestor of the ten groups of plants know as ‘land plants’

• Multicellular, aquatic photosynthetic organisms

What Chara has in common with land plants

• cellulose cell wall

• carbohydrates stored as starch

• Chlorophylls a and b

• Beta-carotene

• Similarities in mechanisms of mitosis and cytokinesis (cell division)

• Similarities in sperm ultrastructure

• Molecular data, Life cycles

Origin of Land Plants

• Approx 480 MYA-410MYA

• First evidence of land plants; cuticle, spores, sporangia

Silurian-Devonian Explosion

• Approx 410-350 MYA

• Most major morphological innovations

  • Stromata

  • Vascular tissue

  • Roots

  • Leaves

Carboniferous

• Approx 350-290MYA

• Lycophytes and Horsetails abundant

• Extensive coal forming swamps

Gymnosperms

• 290MYA-150MYA

• Both wet and dry environments blanketed with green plants for the first time

Angiosperms Abundant

• 150MYA-Present

• Diversification of Flowering Plants

Transfer to Land

Roots, or root like structures, evolved first, followed by the aerial component

Stomata

Small Closable openings in leaves and stems that regulate gas exchange

Cuticle

A coating of waxy lipids that limits water loss

Embryo

A young plant contained in a protective structure

Gametangium

A multicellular organ that encloses plant gametes and keep them from drying out

Chara (genus)

the group of green algae that is the closest relative to land plants

Sporophyte

A multicellular stage of the life cycle that produces haploid gametes

Gametophyte

A haploid cell produced by meiosis that can develop into a multicellular haploid organism

Mosses

• > 12,000 species

• Grow together to form dense mats

• Dense Growth helps water retention

• Rhizoids attach plant to substrate

• Life cycles with noticeable green gametophyte

• Haploid Dominant G

Hepatophyta (Liverworts)

• 6,500 species

• Filmy-like thallus over surface of substrate

• Similar life-cycle to mosses

• Can reproduce asexually from gemmae

Anthrocera (Hornworts)

• 100 Species

• Similar in appearance to liverworts

• Sporophytes are elongated capsules growing out of gametophytes

Generalized Plant Life Cycle

Haploid Dominant Life Cycle (e.g. Mosses)

Alteration of Generations (e.g. Ferns)

Diploid Dominant (e.g. Gymnosperms, Angiosperms)

Evolution Towards Sporophyte Dominant

Lignin

in cell walls to provide structural support in air and intact vessels (woody plants)

Vascular Tissue

• evolved 420-425MYA

• water and nutrients could be absorbed from the group and transported throughout the plant body

  • Plants provide oxygen, food, shelter and stabilize the atmosphere by regulating oxygen, carbon dioxide and water vapor

  • Two Types: Xylem, Phloem

Xylem

• transports water and mineral nutrients from the roots up through the shoot (root + stems)

• Composed of cells with lignin in their cell walls

Phloem

transports sugars and photosynthetic products from the leaves to areas where they are needed throughout the plant body

Carboniferous Age

• Dominated by seedless vascular plants

• Extensive coal deposits form from plants

  • Dead plants accumulate

  • Low oxygen, organic matter decays partially to form peat

  • Under heat and pressure, peat becomes coal

Homospory

• Earliest vascular plants

• Sporophyte produces ONE type of spore

  • spore develops into a single type of gametophyte with both female and male reproductive organs

Heterosporous

• Most vascular plants

• A megaspore develops into a female gametophyte (megagametophyte) that produces only eggs

• microspores develop into male gametophytes (microgametophytes) that produce only sperm

• The sporophyte must develop two types of sporangia

Lycophytes

• 1,000 Species

• Life Cycle can be homosporous and heterosporous

• Very small leaves and single vein microphylls

Microspores

male gametes

Megaspores

female gametes

Horsetails

• Ancient lineage, tree-like in carboniferous

• Whorles tiny leaves, true roots

• Sporangia on strobili

• Most are homosporous; one heterosporous species

• approx 15 species today

• Gametophytes are tine, photosynthetic and free-living

Ferms

• Most Common of the seedless vascular plants

• 12,000 species

• Larger leaves - megaphyll (fronds)

• Branching veins

• Sporophyte large but haploid gametophyte phase is also macroscopic

Fern Life Cycle

• Produce spores in specialized sporangia usually an underside of leaf

• Sproandia in Clusters called sori

• Sporangia may have an annulus - Spore dispersal

• Usually homosporous, occasionally heterosporous

• Gametophytes tiny, fragile like small liverwort

  • alternation of generations

Seed

• Seen in Gymnosperms, Angiosperms

• provide secure and lasting formant stage for the embryo

• means of dispersal

• can be dormant for many years, even centuries

  • food is enclosed in the seed (endosperm)

Seeded Plants

• Gymnosperms and Angiosperms

• Pollenination replaces swimming as transport of sperm to egg

• sporophyte becomes less dependent on gametophyte

  • gametophyte becomes smaller

Cycadophyta (The Cycads)

• Currently 100 Species, tropical and warm climate

• Palm like Leaves

• Seeds and pollen on seperate strobili (cones) of sporophylls

• Male and female strobili on different individuals - dioecious

Ginkgophyta (Gingko)

• “Living Fossil”

• Currently only 1 Species

• Leaves have dichotomous venation

• Dioecious

• seed fruit - like =

• Embryo develops - ovule integument develops fleshy seeds - very unpleasant smell

• Long lived approx 1,000, grow to 30m

• Common Street trees that are deciduoud

Coniferophyta (Conifers)

• usually large trees (pines, spruces, tamarack, cedars. cypresses, redwoods)

• Only 550 species but dominate boreal regions

• Among the tallest, largest, oldest organisms on plant

• Evergreen

• Leaves are needles (megaphylls) covered with waxy cuticle

• Tolerate very cold (dry) habitats

• Responsible for annual global oscillation in atmospheric CO2

LIfe Cycle of a Pine

• Sporophyte dominant

• Sporangia located in Cones

• Heterosporous male and female gametes develop from separate cones

• Gametophytes develop from haploid spores - retained within the sporandia

• Production of mature seeds can take 3 years

• Seeds may develop wings for wing dispersal

• others produce seeds or cones with bright - colored fleshy coatings to attract birds for dispersal

Gentophyta

• Ephedra, Gnetum and welwitchsia

• Floral like strobilus

• vessels present in xylem

• Double fertilization in some

• Illegal production of methamphetamine

  • ephedrine (decongestant)

• closely related to conifers

  • once believed to be transition between gymnosperms and angiosperms

Flowers

specialized reproductive structure to attract pollinators

Fruits

Mature ovaries that contain ovules that will mature into seeds

Gametophytes (Angiosperms)

highly reduced and dependent upon the sporophyte

Pollinations

germinates on the stigma, two sperm required for fertilization

Endosperms

Food for the developing embryo contained in the seed

Flower Parts / Specialized appendages

Sepal, Petal, Stamen and Carpel

Petal

the second ring of appendages

Sepal

the first ring of appendages

Calyx

group of sepals

Corolla

group of petals

Stamen

• male flower parts

  • androecium

Carpels

Female flower parts including stigma, style and ovary

Pollen

produced in the anther

Stigma

sticky surface receives pollen, and pollen grains

Style

hollow tube from stigma to ovary

Ovary

contains ovules (egg cells), contains ovules that ripen to become seed

Complete flowers

has all four different times of appendages (also perfect)

Incomplete Flowers

lack one or more floral “series” (appendages)

Perfect / Bisexual Flowers

had both male and female parts

Imperfect Flowers

either male OR female flowers

Monoecious Plants

male and female flowers on the same plant

Dioecious Plants

male and female flowers are on different plants

Wind and Water Pollination

• flowers tend to be small and simple

• no bright colors or strong odors

Co-evolution

• evolution of a trait in one organism influences the evolution of another

  • colors, odors, sizes and shapes of flowers have evolved in response to the preferences and bodies of their pollinators

Bee pollinated flowers

• Showy, brightly colored, nectar guides

• Distinct markings seen by bees (ultraviolet illumination)

Nectar

a sugar water produced by special glands (nectaries) in the flower