Diversity of Plant Study

1st Characteristic of Plants

Prescence of vacuoles

2nd Characteristic of Plants

Prescence of chloroplast

3rd Characteristic of Plants

Cell Walls that contain cellulose

4th Characteristic of Plants

Life cycle known as alternation of generations

5th Characteristic of Plants

Carb storage as starches

6th Characteristic of Plants

Embryo protection

Alternation of Generations

typical plant life cycle in which a diploid multicellular sporophyte generation alternates with a haploid multicellular gametophyte generation

Plants 1st Ecological Role

primary production (supply food and O₂)

Plants 2nd Ecological Role

providing habitat

Plants 3rd Ecological Role

improving and retaining soil

Plants 4th Ecological Role

regulating climate

Cuticle

waxy substance covering the above-ground parts of a plant; functions to prevent desiccation (so does stomata)

Pores

openings in the cuticle to allow for gas exchange; simple pores without guard cells are only found in liverworts

Stomata

openings in the cuticle to allow for gas exchange that are surrounded by a pair of specialized guard cells

Gametangia

multicellular organs that enclose plant gametes and prevent them from drying out; found in all plants except angiosperms. Contains the archegonium and antheridium

What does archegonium produce?

eggs

what does antheridium produce?

sperm

Sporangium

structure that produces spores

Spores

asexual reproductive cells are capable of developing into a new organism without fusion with another cell.

Thallus

bryophyte plant body: a plant body that lacks vascular tissue

Rhizoid

rootlike hair that anchors a plant and absorbs minerals and water from the soil

Vascular tissue system

the transport system of a vascular plant; transports water, nutrients, and sugars throughout the plant

Xylem

Specialized lignin-reinforced conducting vascular tissue that transports water and mineral solutes upward through the plant body

Phloem

vascular tissue that conducts organic solutes in plants

Sori

a cluster of sporangia, located on the underside of a fern frond

Evergreen

seed plants that shed leaves throughout the year

Deciduous

seed plants that drop all their leaves at one time

Monoecious

male and female organs on the same plant

Dioecious

male and female organs on different plants

Seed

contains a sporophyte embryo packaged with a food supply within a protective seed coat

Pollen grains

produced in microsporangia; consist of the male gametophyte surrounded by the microspore outer wall

Pollination

transfer of pollen grains to the female reproductive organ

Stamen

male flower organ consisting of the anther and filament

Anther

structure on the stamens in which the pollen grains are produced

Carpel

female flower structure consisting of the stigma (sticky pollen landing pad), style, and the ovary containing the ovule(s)

Fruit

structure surrounding angiosperm seeds that is typically derived from matured ovary tissues

Cotyledon

seed leaf for embryo of a flowering plant; provides nutrient molecules for plant until photosynthesis begins

1st Characteristic Land Plants Share with Green Algae

multicellular

2nd Characteristic Land Plants Share with Green Algae

autotrophic

3rd Characteristic Land Plants Share with Green Algae

chloroplasts via primary endosymbiosis

4th Characteristic Land Plants Share with Green Algae

chloroplasts with chlorophylls a and b and 𝛽-carotene

5th Characteristic Land Plants Share with Green Algae

vacuoles

6th Characteristic Land Plants Share with Green Algae

cell wall with cellulose

1st Synapomorphy Found in Land Plants but not Green Algae

ability to live on land

2nd Synapomorphy Found in Land Plants but not Green Algae

embryo protection

3rd Synapomorphy Found in Land Plants but not Green Algae

a complex alternation of generations life cycle

4th Synapomorphy Found in Land Plants but not Green Algae

waxy cuticle

1st Ability plants had to obtain to be able to live on land

maintain moisture

2nd Ability plants had to obtain to be able to live on land

obtain resources from two locations

3rd Ability plants had to obtain to be able to live on land

support of the plant body

4th Ability plants had to obtain to be able to live on land

reproduce without water

What allowed plants to maintain moisture?

Adaptations such as a waxy cuticle and the presence of stomata in some plants help prevent desiccation.

How do land plants support their body?

The molecule lignin strengthens the cell walls of most plants and allows plants to stand tall.

How do land plants reproduce without water?

Some plants disperse sperm via pollen and do not require water for reproduction.

Non-Vascular Plants (bryophytes)

These plants lack vascular tissue and do not produce seeds. Includes mosses and liverworts

What must non-vascular plants rely on?

diffusion to distribute water and nutrients throughout the plant and reproduce

Why do non-vascular plants have to rely on water for reproduction

they have flagellated sperm that must swim from one plant to another to fertilize the egg.

Seed-Free Vascular Plants

These plants have vascular tissue that distributes water, nutrients, and sugars throughout the plant. Because of the vascular tissue, these plants are larger and taller than bryophytes.

What plants are seed-free vascular?

lycophytes and monilophytes (ferns and fern relatives

Do seed-free vascular plants rely on water?

Yes, they are restricted to moist environment since their sperm are flagellated and require water to fertilize an egg.

How are seed-free plants dispersed?

By spores

Gymnosperms or “naked seeds” plants

produce seeds and pollen, significant evolutionary adaptations. A huge amount of diversity and largest plants.

What are seeds primary function?

Protect the developing plant embryo, provide a food source for the plant until germinates and begins pollination, and dispersal

What is pollen primary function?

Allows plants to reproduce without water by carrying sperm from one plant to another

What are gymnosperms characterized by?

the presence of special reproductive structures called cones.

What plants are gymnosperms?

cycads, Ginkgo, and pines.

What are the largest plants?

Gymnosperms

Angiosperms

The most diverse group of plants produces flowers that contain a “vessel” called a carpel.

What are angiosperms characterized by?

by the presence of flowers (specialized reproductive structures) and fruit

How do most angiosperms disperse pollen?

they use animal pollinators.

How does the use of animal pollinators disperse pollen?

The structures of the flowers are specialized for attracting pollinators, which ultimately enhances reproduction.

How are angiosperms subdivided?

Based on morphological differences, 2 categories; monocots and dicots

What are the generations involved in alternation of generations?

the diploid sporophyte and the haploid gametophyte generations. Named for type of reproductive cells they produce.   

Sporophyte

A diploid (2n) multicellular stage in the life cycle of plants and certain algae, which develops from the fertilization of a haploid egg cell and a haploid sperm cell.

Sporangia

specialized structures on the sporophyte. These structures are different in different species of plants. Meiosis occurs within it

Meiosis

results in genetic variation (the daughter cells are genetically different from one another and the parent cell), and it also reduces the chromosome number, or ploidy level. A diploid cell that undergoes meiosis will produce haploid daughter cells.

In plants, what does meiosis produce?

Spores

Gametophyte

the gamete-producing and usually haploid phase, producing the zygote from which the sporophyte arises. It is the dominant form in bryophytes.

How does gametophytes happen?

haploid spores undergo repeated mitotic divisions to produce the multicellular, haploid gametophyte generation.

Mitosis

cell division that results in an increase in the number of cells in an organism.

Gametangia

Specialized, multicellular cells on the gametophyte, produces the gametes

Why can’t the plant go through meiosis after the initial time?

Since the gametophyte is haploid, it cannot undergo meiosis because the chromosome number is already one and cannot be reduced further.

How are eggs and sperm produced?

By mitosis

Since plants have embryo protection, what does the sperm have to do?

the sperm from one gametophyte will swim (or be delivered via pollen in the seed plants) to the egg that remains within the female gametophyte.

Where does fertilization occur?

Within the female gametophyte

Once fertilization happens, what is the ploidy of the zygote?

Diploid

How are sporophyte embryos produced?

zygote must undergoes mitosis

Embryo

the developing stage of a multicellular organism

what must the embryo do to become a sporophyte?

It has to go through mitosis

homosporous

it only produces one type of spore.

heterosporous

they produce two different types of spores that develop into separate male and female gametophytes.  Includes all seeds

In heterosporous, what does meiosis do?

It produces 2 types of spores, microspores and megaspores

Where are megaspores and microspores produced?

within separate structures called microsporangia and megasporangia.

endospory 

the gametophytes develop via mitosis within the wall of the microspores and megaspores.

What happens to the microspores after their produced?

They undergo mitosis to produce the internal multicellular, haploid male gametophyte which is surrounded by the microspore wall - this structure (wall + male) is the pollen grain.

Heterosporous Male Gametophyte

consists of very few cells (or nuclei), including the sperm that will fertilize the female egg.

Heterosporous Female Gametophyte

will develop within the megaspore wall via mitosis. This process takes place within the ovule and will include the development of an egg cell.

Where does fertilization specifically occur for angiosperms?

In the ovule

After fertilization, the embryo will be__

encased in a seed coat with nutrition derived from the gametophyte's tissues, and then released into the environment for dispersal away from the parent plant (which reduces competition for resources)

In a phylogenetic tree, what is the outgroup?

Green Algae