Green Algae and Chlorophytes Overview

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Questions and Answers

Which pigment is primarily responsible for the red coloration of red algae?

Carotene

Chlorophyll a

Phycoerythrin (correct)

Chlorophyll b

What is the main component of foram tests?

Calcium carbonate (correct)

Silica

Cellulose

Chitin

What does the term 'sporophyte' refer to in the Porphyra life cycle?

A spore producing structure

A gamete producing structure

The haploid generation

The diploid generation (correct)

Which of these groups is NOT included in the Archaeplastida supergroup?

Foraminiferans Signup and view all the answers

By what process does a zygote become a germinating spore?

Meiosis Signup and view all the answers

What is the role of pseudopodia in foraminiferans?

To extend through pores in the test for movement and feeding Signup and view all the answers

Green algae are named for what characteristic?

Their grass-green chloroplasts Signup and view all the answers

Which of these is not a characteristic of red algae?

They are exclusively unicellular organisms. Signup and view all the answers

What is the primary structural material of radiolarian tests?

Hydrated silica Signup and view all the answers

Which characteristic is shared by both oomycetes and fungi?

Filamentous hyphae for nutrient uptake Signup and view all the answers

What is the primary function of the micronucleus in ciliates?

Genetic exchange during conjugation Signup and view all the answers

What distinguishes heteromorphic alternation of generations?

Structurally different haploid and diploid forms. Signup and view all the answers

What is the shared characteristic among all rhizarians?

DNA similarities Signup and view all the answers

What is the major ecological role of diatoms?

Major component of phytoplankton Signup and view all the answers

What is the common feature used to classify brown algae as a whole?

Complex, multicellular forms. Signup and view all the answers

How do radiolarians capture their prey?

Through phagocytosis using their pseudopodia Signup and view all the answers

What is the primary shared characteristic of golden algae that gives them their name?

The presence of a yellow and brown pigment in their cells. Signup and view all the answers

Which feature is NOT typically associated with the algal body?

True roots. Signup and view all the answers

What is a key characteristic that defines the Stramenopila clade?

The presence of a 'hairy' flagellum paired with a 'smooth' flagellum. Signup and view all the answers

What is the primary function of the alveoli found in the Alveolata clade?

The function is currently unknown. Signup and view all the answers

What is the proposed origin of the Chromalveolata clade?

A secondary endosymbiosis event originating from a red alga. Signup and view all the answers

What is a distinguishing feature of kinetoplastids?

They have a single mitochondrion with an organized mass of DNA called a kinetoplast. Signup and view all the answers

Which unique structure distinguishes the Euglenozoa clade?

A spiral or crystalline rod inside their flagella. Signup and view all the answers

Which of the following pairs correctly matches an organism to its described characteristic?

Trichomonas vaginalis and undulating membranes. Signup and view all the answers

Study Notes

Chlorophytes

Most chlorophytes live in fresh water, but many are marine.
Some chlorophytes live in damp soil, as symbionts in lichens, or in snow.

Green Algae

Green algae are named for their grass-green chloroplasts (chlorophylls a and b).
Plants evolved from green algae.
Chlorophytes include unicellular, colonial, and multicellular forms.
Two main groups are chlorophytes and charophyceans.

Red Algae and Green Algae

Red algae and green algae are the closest relatives of land plants.
Over a billion years ago, a heterotrophic protist acquired a cyanobacterial endosymbiont.
Photosynthetic descendants evolved into red algae/green algae and glaucophytes.
Land plants evolved from green algae relatives that evolved from the cyanobacterial endosymbiont.
Archaeplastida is a supergroup that includes red algae, green algae, charophytes, glaucophytes, and land plants.

Life Cycle: Porphyra

The life cycle of Porphyra involves both haploid (n) and diploid (2n) stages.
Alternation of generations occurs, starting with a zygote (2n).
Meiosis creates haploid spores (n), which then form gametophytes (n).
Fertilization occurs, restarting the cycle.

Red Algae

Red algae are reddish due to the accessory pigment phycoerythrin, masking chlorophyll's green.
They absorb blue light and reflect/transmit red light.
Color varies from greenish-red in shallow water to dark red/almost black in deep water.
Red algae are usually multicellular, with some being large seaweeds.
Red algae are the most abundant large algae in coastal waters of the tropics.

Forams

Foraminiferans (forams) are named for their porous, multichambered shells (tests) made of calcium carbonate.
Pseudopodia extend through the pores in the test.
Foram tests in marine sediments form an extensive fossil record.

Rhizarians

Rhizarians are a diverse group of protists defined by DNA similarities.
DNA evidence supports Rhizaria as a monophyletic clade.
Amoebas move and feed by pseudopodia; some, but not all belong to the clade Rhizaria.
Rhizarians include forams and radiolarians.

Radiolarians

Marine radiolarians have tests fused into one delicate piece, usually made of silica.
Radiolarians use pseudopodia for engulfing microorganisms via phagocytosis.
Radiolarian pseudopodia radiate from the central body.

Oomycetes

Oomycetes include water molds, white rusts, and downy mildews.
They were once considered fungi based on morphological studies.
Most oomycetes are decomposers or parasites.
Oomycetes have filaments (hyphae) that facilitate nutrient uptake similar to fungi.
Phytophthora infestans, an oomycete, causes potato blight.

Alternation of Generations

A variety of life cycles evolved among multicellular algae.
The most complex life cycles involve alternation of generations, alternating multicellular haploid and diploid forms.
Heteromorphic generations are structurally different, while isomorphic generations look similar.

Diatoms

Diatoms are unicellular algae with unique two-part, glass-like walls of hydrated silica.
Diatoms are major components of phytoplankton.
Diatoms are highly diverse.
Diatoms typically reproduce asexually but can occasionally reproduce sexually.

Ciliates

Ciliates are a large group of diverse protists, named for their cilia for movement and feeding in fresh water.
They have large macronuclei, small micronuclei, and are complex cells.
Micronuclei function during conjugation, a sexual process that creates genetic variation.
Conjugation is separate from reproduction, which generally occurs by binary fission within the same species.

Brown Algae

Brown algae are the largest and most complex algae.
Brown algae are multicellular and mostly marine.
Brown algae include many species commonly called "seaweeds."
The algal body (thallus) is plant-like but lacks true roots, stems, and leaves.
Holdfasts anchor the stem-like stipe, which supports leaf-like blades.

Golden Algae

Golden algae are named for their color from yellow and brown carotenoids.
Golden algae cells are typically biflagellated.
All golden algae are photosynthetic and some are heterotrophic.
Most are unicellular but some are colonial.

Stramenopiles

The Stramenopila clade includes several groups of heterotrophs and algae.
Most have a "hairy" flagellum paired with a "smooth" flagellum.

Alveolata

Alveolates (a clade: Alveolata) have membrane-bounded sacs (alveoli) beneath the plasma membrane.
The function of the alveoli is unknown.
Alveolata includes dinoflagellates, apicomplexans, and ciliates.

Apicomplexans

Apicomplexans are all animal parasites, causing serious human diseases.
One end, the apex, contains a complex of organelles specialized for penetrating hosts.
Apicomplexans have sexual and asexual stages requiring multiple host species to complete their life cycle. Plasmodium is the parasite causing malaria
Continuously changes surface proteins.
Requires mosquitoes and humans for life cycle completion.
Two million people die from Malaria each year.

Kinetoplastids

Kinetoplastids have a single mitochondrion containing a kinetoplast (DNA mass).
Kinetoplastids include free-living consumers of prokaryotes, particularly in freshwater, marine, or moist terrestrial ecosystems.
This group includes Trypanosoma, causing sleeping sickness in humans.
Frequent changes in surface proteins prevent host immunity (like in Plasmodium).

Euglenozoans

Euglenozoa is a diverse clade including predatory heterotrophs, photosynthetic autotrophs, and pathogenic parasites.
Distinguished by a spiral or crystalline rod of unknown function within the flagella.
Includes kinetoplastids and euglenids. Euglenids have one or two flagella that emerge from a pocket at one end of the cell. Some species are both autotrophic and heterotrophic (mixotrophic) and contain chloroplasts..

Diplomonads and Parabasalids

Diplomonads and parabasalids are single-celled protists.
Diplomonads have two nuclei. Giardia intestinalis is an example.
Parabasalids have undulating membranes. Trichomonas vaginalis is an example.

Dinoflagellates

Dinoflagellates are a diverse group of aquatic mixotrophs and heterotrophs.
They are abundant components of both marine and freshwater phytoplankton.
They have a characteristic shape reinforced by internal cellulose plates; some contain chloroplasts.
Two flagella allow them to spin through the water. Dinoflagellate blooms cause toxic red tides.

Chromalveolates

Some data suggest that the clade Chromalveolata is monophyletic, originating in a secondary endosymbiosis event.
The proposed endosymbiont is a red alga.
This clade includes alveolates and stramenopiles.

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Description

This quiz explores the world of green algae and chlorophytes, highlighting their habitats, characteristics, and evolutionary significance. Delve into the relationship between green algae and land plants, including the details of their life cycles and classification. Test your knowledge on these fascinating organisms!