Bio 214: Green Algae

Green Algae

Classified as part of clade Viridiplantae, includes around 22,000 species, evolutionary ancestors of plants.

Viridiplantae

A clade that includes green algae and the entire plant kingdom.

Chlorophyta

One of the major groups of green algae, characterized by their chlorophyll content.

Charophyta

Freshwater group of green algae proposed as direct ancestors to land plants.

Photosynthesis

The process by which green algae convert light energy into chemical energy, producing oxygen.

Zygospores

Gametes formed by nuclear fusion in green algae, which are dormant during adverse conditions.

Zoospores

Flagellated, asexual spores produced by green algae, typically having two flagella.

Diplobiontic life cycle

A life cycle in which both haploid and diploid generations are multicellular.

Haplobiontic life cycle

A life cycle characterized by a multicellular haploid gametophyte and a unicellular diploid phase.

Endosymbiosis

The process by which certain algae acquired chloroplasts from cyanobacteria, enabling photosynthesis.

Chlorophyll a & b

Pigments found in green algae that capture light energy for photosynthesis.

Which of the following statements about plant divisions is false?

1. Lycophytes and monilophytes are seedless vascular plants.

2. All vascular plants produce seeds.

3. All non-vascular embryophytes are bryophytes.

4. Seed plants include angiosperms and gymnosperms.

2. All vascular plants produce seeds.

Which of the following statements about the moss life cycle is false?

1. The mature gametophyte is haploid.

2. The sporophyte produces haploid spores.

3. The calyptra buds to form a mature gametophyte.

4. The zygote is housed in the venter

3. The calyptra buds to form a mature gametophyte.

Which of the following statements about the fern life cycle is false?

1. Sporangia produce haploid spores.

2. The sporophyte grows from a gametophyte.

3. The sporophyte is diploid and the gametophyte is haploid.

4. Sporangia form on the underside of the gametophyte.

4. Sporangia form on the underside of the gametophyte.

The land plants are probably descendants of which of these groups?

1. green algae

2. red algae

3. brown algae

4. angiosperms

1. Green algae

Alternation of generations means that plants produce:

1. only haploid multicellular organisms

2. only diploid multicellular organisms

3. only diploid multicellular organisms with single-celled haploid gametes

4. both haploid and diploid multicellular organisms

4. both haploid and diploid multicellular organisms

Which of the following traits of land plants allows them to grow in height?

1. alternation of generations

2. waxy cuticle

3. tracheids

4. sporopollenin

c. Tracheids

How does a haplontic plant population maintain genetic diversity?

1. Zygotes are produced by random fusion.

2. Gametes are created through meiosis.

3. Diploid spores undergo independent assortment during mitosis.

4. The zygote undergoes meiosis to generate a haploid sporophyte.

a. Zygotes are produced by random fusion.

What characteristic of Charales would enable them to survive a dry spell?

1. sperm with flagella

2. phragmoplasts

3. sporopollenin

4. chlorophyll a

c. Sporopollenin

Which one of these characteristics is present in land plants and not in Charales?

1. alternation of generations

2. flagellated sperm

3. phragmoplasts

4. plasmodesmata

1. alternation of generations

A scientist sequences the genome of Chara, red algae, and a tomato plant. What result would support the conclusion that Charophytes should be included in the Plantae kingdom?

1. The Chara genome is more similar to the red algae than the tomato plant.

2. All three genomes are distinctly different.

3. The Chara genome is more similar to the tomato plant genome than the red algae genome.

4. The tomato plant genome is distinct from the red algae genome.

c. The Chara genome is more similar to the tomato plant genome than the red algae genome.

Which of the following features does not support the inclusion of Charophytes in the Plantae kingdom?

1. Charophyte chloroplasts contain chlorophyll a and b.

2. Charophyte plant cell walls contain plasmodesmata to allow transfer between cells within multicellular organisms.

3. Charophytes do not exhibit growth throughout the entire plant body.

4. Charophytes are multicellular organisms that lack vascular tissue.

c. Charophytes do not exhibit growth throughout the entire plant body.

Which of the following structures is not found in bryophytes?

1. a cellulose cell wall

2. chloroplast

3. sporangium

4. root

d. Root

Stomata appear in which group of plants?

1. Charales

2. liverworts

3. hornworts

4. mosses

d. Mosses

The chromosome complement in a moss protonema is:

1. 1n

2. 2n

3. 3n

4. varies with the size of the protonema

a. 1n (haploid)

Why do mosses grow well in the Arctic tundra?

1. They grow better at cold temperatures.

2. They do not require moisture.

3. They do not have true roots and can grow on hard surfaces.

4. There are no herbivores in the tundra.

Oc. They do not have true roots and can grow on hard surfaces.

A botanist travels to an area that has experienced a long, severe drought. While examining the bryophytes in the area, they notice that many are in the same life-cycle stage. Which life-cycle stage should be the most common?

1. zygote

2. gametophyte

3. sporophyte

4. archegonium

b. Gametophyte

Microphylls are characteristic of which types of plants?

1. mosses

2. liverworts

3. club mosses

4. ferns

3. Club mosses

A plant in the understory of a forest displays a segmented stem and slender leaves arranged in a whorl. It is probably a ________.

1. club moss

2. whisk fern

3. fern

4. horsetail

4. Horsetail

The following structures are found on the underside of fern leaves and contain sporangia:

1. sori

2. rhizomes

3. megaphylls

4. microphylls

1. Sori

The dominant organism in fern is the ________.

1. sperm

2. spore

3. gamete

4. sporophyte

4. Sporophyte

What seedless plant is a renewable source of energy?

1. club moss

2. horsetail

3. sphagnum moss

4. fern

3. sphagnum moss

How do mosses contribute to returning nitrogen to the soil?

1. Mosses fix nitrogen from the air.

2. Mosses harbor cyanobacteria that fix nitrogen.

3. Mosses die and return nitrogen to the soil.

4. Mosses decompose rocks and release nitrogen.

1. Mosses decompose rocks and release nitrogen.

The production of megaphylls by many different species of plants is an example of _____.

1. parallel evolution

2. analogy

3. divergent evolution

4. homology

2.parallel evolution

Why did land plants lose some of the accessory pigments present in brown and red algae?

Land plants evolved in environments with full-spectrum sunlight, so they no longer needed the extra pigments (like fucoxanthin or phycobilins) used by algae to absorb light in deeper or filtered water.

What is the difference between extant and extinct?

Extant means a species is still living today; extinct means the species no longer exist

Describe at least two challenges that cactuses had to overcome that cattails did not.

1) Water scarcity – cactuses adapted to survive in dry deserts, unlike cattails that live in wetlands. 2) Intense sunlight – cactuses developed thick stems and spines to reduce water loss and protect from harsh sun, while cattails grow in shaded or moist environments.

Describe a minimum of two ways that plants changed the land environment to support the emergence of land animals.

1) Plants produced oxygen through photosynthesis, increasing atmospheric oxygen levels needed by animals. 2) Plants stabilized soil and created habitats, making land more livable and providing food sources for herbivorous animals.

To an alga, what is the main advantage of producing drought-resistant structures?

It allows the alga to survive dry periods and resume growth when water becomes available again.

In areas where it rains often, mosses grow on roofs. How do mosses survive on roofs without soil?

Mosses absorb water and nutrients directly through their leaves, so they don’t need soil to survive. They anchor themselves with rhizoids instead of roots.

What are the three classes of bryophytes?

Mosses, liverworts, and hornworts.

Describe two adaptations that are present in mosses, but not hornworts or liverworts, which reflect steps of evolution toward land plants.

1) Mosses have stomata on their sporophytes for gas exchange. 2) Mosses have more developed, upright sporophytes, helping with spore dispersal above ground.

Bryophytes form a monophyletic group that transitions between green algae and vascular plants. Describe at least one similarity and one difference between bryophyte reproduction and green algae reproduction.

Similarity: Both require water for sperm to swim to the egg.

Difference: Bryophytes have a multicellular embryo that stays attached to the parent plant; green algae do not.

How did the development of a vascular system contribute to the increase in size of plants?

The vascular system (xylem and phloem) allowed plants to transport water, nutrients, and sugars efficiently, supporting taller growth and larger structures.

Which plant is considered the most advanced seedless vascular plant and why?

Ferns are considered the most advanced seedless vascular plants because they have well-developed vascular tissue, true roots, stems, and large leaves (megaphylls) that support efficient nutrient transport and spore dispersal.

Ferns are simultaneously involved in promoting rock weathering, while preventing soil erosion. Explain how a single plant can perform both these functions, and how these functions are beneficial to its ecosystem.

Fern roots release acids that break down rocks (weathering), while their roots and fronds hold soil in place, preventing erosion. These actions help form and stabilize soil, creating better conditions for other plants and organisms in the ecosystem.

adventitious

describes an organ that grows in an unusual place, such as a roots growing from the side of a stem

antheridium

male gametangium

archegonium

female gametangium

capsule

case of the sporangium in mosses

charophyte

other term for green algae; considered the closest relative of land plants

club mosses

earliest group of seedless vascular plants

diplontic

diploid stage is the dominant stage

embryophyte

other name for land plant; embryo is protected and nourished by the sporophyte

extant

.still-living species

extinct

no-longer-existing species

fern

seedless vascular plant that produces large fronds; the most advanced group of seedless vascular plants

gametangium

structure on the gametophyte in which gametes are produced

gemma

(plural, gemmae) leaf fragment that spreads for asexual reproduction

haplodiplodontic

haploid and diploid stages alternate

haplontic

haploid stage is the dominant stage

heterosporous

produces two types of spores

homosporous

produces one type of spore

hornworts

group of non-vascular plants in which stomata appear

horsetail

seedless vascular plant characterized by joints

lignin

complex polymer impermeable to water

liverworts

The most primitive group of non-vascular plants characterized by flattened, leaf-like structures, lacking true stems and roots. They typically grow in moist environments and reproduce primarily via spores, exhibiting a simple structure with either thallus or leafy forms. Liverworts can be divided into two main categories: leafy liverworts, which resemble small leaves, and thallose liverworts, which are flat and ribbon-like.

lycophyte

Club moss; one of the earliest groups of seedless vascular plants. They are characterized by their small leaves called microphylls, which have a single unbranched vein. Lycophytes reproduce via spores and include subgroups such as club mosses and quillworts.

megaphyll

larger leaves with a pattern of branching veins

megaspore

female spore

microphyll

small size and simple vascular system with a single unbranched vein

microspore

male spore

mosses

Group of bryophytes characterized by small, leafy structures that form dense green clumps in moist environments. They have a primitive conductive system that allows them to transport water and nutrients, although they lack true roots, stems, and leaves. Mosses primarily reproduce via spores and play a crucial role in ecosystems by preventing soil erosion and aiding in the formation of soil.

non-vascular plant

plant that lacks vascular tissue, which is formed of specialized cells for the transport of water and nutrients

peat moss

Sphagnum, a type of moss that forms peat and is significant for carbon storage, water retention, and creating bog ecosystems. It helps to retain moisture and provides a habitat for various organisms.

peristome

tissue that surrounds the opening of the capsule and allows periodic release of spores

phloem

tissue responsible for transport of sugars, proteins, and other solutes

protonema

tangle of single-celled filaments that forms from the haploid spore

rhizoids

thin filaments that anchor the plant to the substrate

seedless vascular plant

A plant that does not produce seeds, reproducing instead through spores. This group includes ferns, horsetails, and club mosses, which have vascular tissue for the transport of water and nutrients, allowing them to grow larger than non-vascular plants.

seta

stalk that supports the capsule in mosses

sporocyte

diploid cell that produces spores by meiosis

sporophyll

leaf modified structurally to bear sporangia; these specialized leaves play a vital role in plant reproduction by producing and housing spores, enabling the plant to reproduce and disperse its genetic material.

sporopollenin

Tough polymer surrounding the spore, providing protection against desiccation and chemical damage. It plays a crucial role in the survival of spores during unfavorable environmental conditions. Sporopollenin is found in the spores of all land plants, including bryophytes (mosses, liverworts, hornworts), seedless vascular plants (ferns, horsetails, club mosses), and seed plants (angiosperms and gymnosperms).

streptophytes

A group that includes green algae and land plants. They are characterized by similarities in cell structure, such as the presence of unique chloroplasts, reproductive features like the formation of embryophytes, and genetic evidence indicating a close evolutionary relationship, suggesting that land plants evolved from streptophyte algae.

strobili

cone-like structures that contain the sporangia

tracheophyte

A vascular plant that contains specialized tissues (xylem and phloem) responsible for the transport of water, nutrients, and sugars throughout the organism.

vascular plant

plant containing a network of cells that conducts water and solutes through the organism

vein

bundle of vascular tissue made of xylem and phloem

whisk fern

Whisk ferns are seedless vascular plants that belong to the Phylum Pteridophyta. They lack true leaves and roots, consisting mainly of stems with small scales or appendages. They reproduce via spores produced in sporangia located along the stems.

xylem

tissue responsible for long-distance transport of water and nutrients