Section 10.5 How is meiosis involved in the production of

Take a few moments to review the discussions before you start this chapter.

Beaches are closed to protect swimmers from amoeba infections.

A sample of a boy's brain tissue is in the center of a plate. The boy had a high temperature, stiff neck, and vomited five days ago.

He died before more tests could be done because antibiotics didn't help. He and his family went to the lake at the start of the heat wave. Stirred up from the bottom by the boy's boisterous play, the amoeba likely entered his nose during a handstand attempt and burrowed toward his brain, almost guaranteeing his death.

In the same lake where the boy was bitten, there are critical species that produce oxygen, and form the base of the aquatic food chain.

Understand that protists represent more than one evolutionary line.

Some are colonies of cells and others are multicellular. Protists have membranous organelles that serve as the energy centers of the cell.

The theory suggests that the free living bacterium that formed a symbiotic relationship with the host cell gave rise to the mitochondria and plastids. Mitochondria and chloroplasts were derived from the same source as the aerobic bacterium. The life processes of the host are now complemented by the genomes of the endosymbioticbacteria.

Protists range in size from small organisms to large organisms that can reach 200 m in length. Despite their small size, protists have a high level of complexity. The contractile vacuole is an organelle that helps in water regulation.

Some protists are grouped according to how they acquire organic nutrition. The photoautotrophic protists are a diverse group. Heterotrophic protists get organic compounds from the environment.

Protists can reproduce sexually and asexually. In protists, asexual reproduction is the norm.

The protist life cyle can survive until favorable conditions return. cysts are formed for the transfer to a new host.

Many protists cause diseases in humans. The foundation of the food chain in both freshwater and saltwater are aquatic photoautotrophic protists.

Protists used to be classified as a single kingdom. Evidence shows that protists are not all from the same evolutionary line. The plants, fungi, and animals are classified into five supergroups. A is a high-level group below the kingdom.

The data is used to determine the relatedness of the groups. The simplified tree does not include all of the members of the supergroup.

The origin of the first eukaryotes can be seen in the long and old protist lineages. The history of humans is less complete the further back in time we look, as we can be less and less certain about how they are related to each other. New research in the evolution of protists has helped to clarify some of the evolutionary relationships among eukaryotes, but much research still needs to be done.

We look at the various supergroups into which protists and other eukaryotes have been placed based on our understanding.

Plants and protists are included in the eukaryote supergroups, as are fungi, animals, and protists.

They live in oceans, fresh water, snowbanks, the bark of trees, and the backs of turtles. Some of the 8,000 species of green algae have symbiotic relationships with plants, animals, and fungi.

The majority are single celled. Seaweeds look like lettuce leaves. Greenalga are not always green, some have additional pigments that give them an orange, red, or rust color.

There are two groups of green algae, the and the charophytes. Green algae are thought to be related to land plants.

A bright red eyespot helps guide individuals toward light.

As many as 16 daughter cells can form inside the parent cell wall when there are two haploid daughter cells. Each daughter cell creates a cell wall. The functional haploid daughter cells emerge from within the parent by secreting anidase that digests the parent cell wall.

During sexual reproduction, all structures are haploid, and meiosis follows the zygospore stage, which is the only diploid part of the cycle.

Two different types of cells come into contact and form a diploid zygote. A heavy wall forms around the zygote, which undergoes a period of dormancy in which it is resistant to unfavorable conditions. Four haploid zoospores are produced by meiosis when conditions improve. The haploid flagellated zoospores grow to become adult cells and complete the life cycle.

There are many colonial forms among the flagellated chlorophytes.

The daughter colony escapes from the parent colony by releasing an enzyme that wipes out part of the colony.

There are charophytes. End-to-end chains of cells are called thread.

There are Charophytes on aquatic flowering plants. Others attach objects to the water column.

It has spiraled chloroplasts. During a temporary union, the cells exchange genetic material. Two haploid filaments line up parallel to each other, and the cell contents of one of them move into the other. In the spring, diploid zygospores undergo meiosis to produce new haploid filaments.

The formation of zygote follows.

It's called a stonewort because it's encrusted with calcium carbonate.

New cells are only produced at the upper end of the main strand. There are whorls of branches between the giant cells of the main strand. Each branch has a single-file thread of cells.

The male and female structures produce sperm and an egg. A diploid zygote is retained until it is enclosed by tough walls.

The stoneworts are most closely related to land plants according to the data.

The red algae are multicellular seaweeds that possess red and blue which transfer energy from absorbed light to the photopigment chlorophyll during photosynthesis. They live in warm seawater, some at depths greater than 70 m.

Most of the more than 7,000 species of red algae are much smaller and more delicate than brown algae, but some species can exceed a meter in length. Most red algae have feathery, flat, or ribbonlike branches. Coralline red algae have cell walls that contain calcium carbonate, a mineral that contributes to the growth of coral reefs.

The economic importance of red algae is important. Agar can be used to make vitamins and drugs, as a base for cosmetics, and as a material for making dental impressions. Agar is used in the laboratory to make a culture medium. It becomes the gel for electrophoresis when it is purified. Agar is used in food preparation as an antidrying agent for baked goods.

Carrageenan is used in the production of chocolate and cosmetics.

Do you know the characteristics of supergroup SAR members?

The Page 380 stramenopiles, the alveolates, and the rhizaria are part of the SAR supergroup. The rhizarians have been classified as a separate group. The stramenopiles and alveolates were in a supergroup called Chromalveolata. The formation of the new SAR supergroup was the result of closer relationships between all three.

The stramenopiles include the brown algae, diatoms, golden brown algae, and water molds.

The brown algae range from small forms to large multicellular forms that can reach 100 m in length. Most of the species live in the ocean.

They live along rocky coastlines.

The multicellular brown algae are seaweeds that live on the rocky coast. As the tide comes in, they are exposed to dry air as the tide goes out. They dry out slowly because of the water retention material in their cell walls.

They have a holdfast that allows them to cling to rocks.

Human food andfertilizer can be obtained from brown algae.

A diatom is a single-celled stramenopile with an ornate shell.

The valves that fit together in the shell are upper and lower shelves. Diatoms have an orange-yellow color due to their accessory pigment. plankton is a source of oxygen and food for Heterotrophs in both freshwater and marine environments.

Asexual reproduction happens when diploid parents undergo a procedure to make two diploid daughter cells. When a diatom reproduces asexually, the size of the daughter cells decreases until they reach 30% of their original size.

They start to reproduce sexually at this point. Gametes are produced by the diploid cell. Gametes grow a diploid zygote and 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609-

The valves of diatoms are covered with a variety of striations and markings that form beautiful patterns under the microscope. The depressions are where the organisms make contact with the outside environment. The remains of diatoms accumulate on the ocean floor and are mined for use as filters, soundproofing materials, and gentle polishing abrasives.

The golden brown algae have yellow-brown accessory pigments. The cells of these single-celled or colonial protists have two flagella with tubular hairs. Golden brown algae cells can be naked, covered with organic or silica scales, or enclosed in a cagelike structure called a lorica. The golden brown algae contribute to freshwater and marine plants.

The stramenopiles have a type of flagella. There are rows of tubular hairs on the longer flagella.

Water mold are often seen as furry growths on their food source. Water molds are parasites and live on land. There are over 700 species of Page 382 water molds. Most water molds live off dead organic matter.

Water mold, also called oomycetes, used to be grouped with fungi, because they are similar to fungi in many ways. The water mold's body is similar to the hyphae of fungi, but its cell walls are made of a different material.

Water molds can reproduce both asexually and sexually.

During sexual reproduction, structures called oogonia, which produce haploid eggs, and antheridia, which produce haploid sperm, form. When the antheridium and oogonium come in contact, sperm and eggs come together. Eggs and sperm produce diploid zoospores, which emerge from the oogonium.

Alveolates are single-celled organisms.

The dioflagellates are encased by protective plates. One flagellum acts as a rudder and the other causes the cell to spin as it moves forward.

There are many species of dinoflagellates.

An important source of food for small animals in the ocean is dinoflagellates.

Zooxanthellae are dinoflagellates that form relationships with other organisms. Zooxanthellae live within their hosts. The dinoflagellates lack flagella. Corals in the animal kingdom usually contain large numbers of zooxanthellae, which provide their animal hosts with organic nutrition. The corals give the zooxanthellae shelter, food, and protection.

One of the most important groups of primary producers is the dinoflagellates. A population explosion of dinoflagellates and other algae is called a algal bloom. A single liter of water can contain more than 30,000 organisms. The high density of the algae causes some blooms to turn the water brown or red. Red tides can be seen from space.

A red tide is caused by a dinoflagellate bloom in southeastern Alaska. A fish kill on Padre Island, Texas, can be the result of a dinoflagellate bloom. Half of the parent's plates are passed on to each daughter cell. The daughter cells act as gametes and form a diploid zygote during sexual reproduction. After entering a resting stage, the zygote undergoes meiosis. The product of meiosis is a single haploid cell.

The protists are single-celled. They are the most complex and specialized of all the organisms.

The barbed threads that are discharged by trichocysts are useful for defense and for capturing prey. The poisons are released by some trichocysts.

Ciliates are the most complex of the protists. Take note of the oral grooves, gullet, and anal pore. Sexual reproduction called conjugate occurs occasionally.

The non-digestible reagent is eliminated through the anal pore after the digestion.

The ciliates range in size from 10 to 3000 um. The majority of the ciliates are free living, mobile, and single celled.

They are one of the largest single-celled organisms.

Ciliates have two types of nuclei, a large macronucleus and one or more small micronuclei. The normal metabolism of the cell is controlled by the macronucleus. During sexual reproduction, two ciliates unite and exchange haploid micronuclei. The fusion of the micronuclei results in the dissolution of the macronuclei.

An apicoplast is a unique organelle that is used to penetrate a host cell. There are parasites of animals and some of them can spread.

When the cells burst and release toxic substances into the blood, there are chills and the symptoms of Malaria.

Malaria kills more than half a million people each year. In densely populated, tropical areas of the globe, Malaria is the most common disease. Half the world's population is at risk for the disease because of its prevalence in these areas.

There are other human parasites.

In the United States, there have been cases of cyclosporiasis caused by contaminated fresh fruits and vegetables. In pregnant women, the parasites can cause birth defects and intellectual disability, and in AIDS patients, it can cause neurological problems.

rhizarians are no longer classified as a unique supergroup.

A test is a skeleton of Foraminiferans and radiolarians.

The tests of foraminiferans and radiolarians are beautiful. The calcium carbonate test is often multichambered. The pseudopods extend through openings in the test. In the radiolarians, the glassy Silicon test has a radial arrangement of spines. The pseudopods are not inside the test.

When a geological upheaval occurred, there were so many fossilized shells that they became a large part of the White Cliffs. The pseudopods extend out through the openings of the shell.

There is a layer of dead foraminiferans and radiolarians on the ocean floor. The presence of tests is used as an indicator of oil deposits. Their fossils are evidence of the antiquity of the protists. Each geological period has a distinctive form of foraminiferan; thus, foraminiferans can be used as index fossils.

There were millions of years of foraminiferan deposits along the southern coast of England. The great Egyptian pyramids are made of foraminiferan limestone.

"hollow" have atypical or absent mitochondria and flagella.

The euglenids are single-celled freshwater organisms. Euglenid classification is problematic because they are very diverse. Heterotrophic, mixotrophic, and photo autotrophic are some of the terms used for the euglenids.

The rest of the genera do not. Those without chloroplasts eat or absorb food.

The chloroplasts are surrounded by three instead of two. The pyrenoid is a region of the chloroplast. Paramylon is an unusual type ofCarbohydrate produced by Euglenids.

The tinsel flagellum has an eyespot that can detect light.

A vacuole removes excess water.

Sexual reproduction is not known to occur.

There are single-celled, flagellated excavates of animals. They can survive in low-oxygen environments. The protozoans rely on fermentation for the production of ATP. A variety of forms are found in the guts of the termites.

There is a unique connection between the Golgi apparatus and flagella. Vaginitis is caused by infections.

The male may have no symptoms after being exposed to Page 386.

There are two sets of flagella in the "unit") cell. A variety of mammals have this protozoan in their guts.

This diplomonad can be found on any surface, including cells.

After the disk detaches, characteristic markings can be seen.

Humans are passed on Trypanosomes by insects. Lack of oxygen to the brain is the cause of the disease's lethargy. Thousands of cases are diagnosed each year. Brain damage is a common cause of death.

The general structure is shown in the drawing. 7 million people are affected by this parasites.

African sleeping sickness is the most lethal of the NTDs.

The tsetse fly is the cause of the disease because it carries trypanosomes and protists into the human bloodstream. The relationship between humans, the tsetse fly, and domestic livestock is shown in Figure 21B.

As many as 10,000 people are affected by this disease. If caught early enough, it can be cured with medication, but it's hard to get it in poor nations. The disease is fatal without treatment.

The World Health Organization reports that the number of new cases of sleeping sickness has dropped to the lowest levels in 50 years because of an effort to eliminate the tsetse fly from these lands. Efforts by public health agencies and the WHO to control tsetse populations have resulted in a decline in the incidences of new cases.

It can be transmitted from one person to another.

There are moist tropical regions of Africa where sleeping sickness is found.

There are two excavates that cause human diseases.

The features of amoebozoans are unique.

Pick out the members of the supergroup.

protozoans are animals that move. Pseudopods form when an amoebozoan's microfilaments contract and extend.

Amoebozoans live in aquatic environments where they are a part of the plankton.

Primary amobic meningoencephalitis is caused by the amoeba feeding on brain cells.

Most protists are beneficial to human welfare. Protists living in oceans and lakes produce half of the oxygen we breathe. All of those benefits won't mean much if you're the person who's been exposed. Prevention is the key to reducing infections.

Climate change may make infections like the boy's more common because of changes in humans and protists.

Climate change is a rise in average global temperature due to the introduction of carbon dioxide, methane, ozone, and nitrous oxide gases to the atmosphere from human-influenced sources. Extreme weather events, such as floods, have gone up due to increased temperatures. Famine, displacement, and changing behaviors have been caused by this.

The pathogen took the lives of two children because of higher than normal summer temperatures.

The human behavior that makes the pathogen more likely is influenced by changing climate.

Climate change may cause both pathogens and humans to be closer to infectious encounters.

The characteristics, ecology, and diversity of protists are discussed in this chapter. Understanding those factors and how they will be affected by climate change is the key to preventing increased infections by protists and the loss of beneficial protist species.

Meningoencephalitis is caused by the cyst stage of the freshwater amoeba.

The rate of protist-related human diseases may increase as a result of climate change.

The amoeboids are protists that eat with pseudopods. There are hundreds of species of amoeboids. Amoeboids feed by phagocytosis, by which they destroy their prey with a pseudopods.

In freshwater ponds, this amoeboid is common. Contractile vacuoles remove excess water while food vacuoles absorbbacteria and other organisms.

Water and food can be contaminated with cysts.

Dead plant material is fed on by slimy molds.

Slime molds have flagellated cells at some point during their life cycle, unlike fungi, who have cell walls.

The molds are mobile and amoeboid. The moulds produce meiosis, which causes the spores to form gametes.

There are nearly 1,000 species of slime molds.

When conditions are unfavorable to growth, the diploid adult forms sporangia. Haploid amoeboid or flagellated cells are released.

The plasmodium develops Page 391 when conditions are unfavorable. "seed" is a reproductive structure. A fruiting body is an aggregate of sporangia. The plasmodial slime mold sporangium can survive if there is enough humidity. There are either a haploid flagellated cell or an amoeboid cell in plasmodial slime molds. A multinucleated plasmodium is produced once again when two haploid cells form a zygote that feeds and grows.

Individual amoeboid cells exist as cellular slime molds. They are common in the soil. There are less species of cellular slime molds compared to plasmodial species.

The pseudoplasmodium stage is temporary and eventually gives rise to a fruiting body.

The asexual cycle begins again when favorable conditions return.

The animals and fungi are called opisthokonts. The supergroup includes both single-celled and multicellular organisms. The choanoflagellates are filter feeders with cells that bear a striking collar of slender microvilli.

Nucleariids do not have the characteristic cell walls found in fungi, but they are close relatives.

Some protists may be multicellular or exist in colonies.

Protists exhibit asexual reproduction in favorable environmental conditions.

Large, complex brown seaweeds are economically important. The golden brown algae has an outer layer of silica.

Water molds produce diploid zoospores, but not flagellated ones.

The parasites are nonmotile.

The test results of foraminiferans and radiolarians can be used as fossils on the ocean floor.

Euglenids have a pellicle instead of a cell wall. Chagas disease and African sleeping sickness are caused by parasites that are transmitted by the bite of an insect.

Amoeboids move and feed on each other.

They have an amoeboid stage.

Pick the best answer for the question.

Mitochondria in protists came from a different type ofbacteria.

Usually reproduce sexually.

A move by pseudopods.

rhizarians form skeletons and can be used to date fossils.

Protists with deep oral grooves are known as excavates.

The amoeboid vegetative state of plamodial and cellular _____ is important.

Roughly half of the photosynthesis on Earth is performed by protists in the oceans.

A new anti-termite chemical will not harm the environment. If they can't digest wood, they will starve.

Some protist species cause diseases that are difficult to treat and can be deadly.

unrelated species evolve similar adaptations to their environment through convergent evolution. Birds and bats have evolved their ability to fly on their own. Parasitism is an example of protists.

The ability to parasitize human hosts has been evolved by certain apicomplexans in the excavata supergroup.