Protista

Protista is a large group of eukaryotic organisms. This kingdom does not lie under kingdoms like Plantae, Animalia, or Fungi. Most of these organisms are single-celled and are simple. They also include some basic multi-celled organisms. They are often found in freshwater, marine environments, and on land. These organisms have different ways of getting food. They can be autotrophic and sometimes heterotrophic.

Protista carries a great importance while studying evolution. They are among the earliest eukaryotes. They also have a major role in the ecosystem. Some of them can cause disease too.

How are Protists Classified?

Protists have many different characteristics. That is why they are one of the most diverse groups of organisms. The protists are classified based on different criteria like – cell structure, mode of nutrition, movement, and reproduction. They are also classified based on three major groups, mentioned further.

Mentioned below are the details of the classification based on these different criteria.

Cell Structure

• Protists are eukaryotic creatures known for their complex cell structures.
• Their genetic material, or DNA, is contained in a true nucleus
• The nucleus is encircled by a nuclear membrane.
• Organelles like mitochondria are present for energy.
• Occasionally, chloroplasts are also present in their cells for photosynthesis.
• Endoplasmic reticulum and the Golgi apparatus help in the synthesis of proteins and lipids.

Mode of Nutrition

1. Some protists are autotrophic.
2. They get their food through photosynthesis, like Algae.
3. Many of them are heterotrophic.
4. They feed on organic matter to get nutrients, like Amoeba.
5. Mixotrophs can be both autotrophic as well as heterotrophic.
6. They can switch between both nutrients based on food availability.

Reproduction

• They can reproduce through both asexual and sexual modes.
• The asexual mode includes binary fission and budding.
• Sexual mode is done via the fusion of gametes.

Movement

• They use cilia, flagella, or pseudopodia for movement.

Protista Classification Based on Plant, Animal, and Fungus Groups

Protista is broadly classified into three main groups: Such as:

1. Plant-like protists- Algae
2. Animal-like protists- Protozoa
3. Fungus-like protists- Moulds

Algae

These are self-feeding organisms and mostly undergo photosynthesis. Mostly they are found in marshes and other water bodies. They play a key role in oxygen generation. Example:

1. Diatoms: They have silica in their cell.
2. Green Algae: They contain chlorophyll in them.

Protozoa

These are heterotrophic and can be free-living or parasitic. They help in nutrient cycling. This group also shows locomotion. Example:

1. Amoebas use pseudopodia to move.
2. Paramecium uses cilia.

Moulds

These are saprophytic organisms as they mostly feed on dead tissues. Example:

1. Slime Moulds move like amoeba
2. Water molds grow in water and are plant parasites.

What Are The Ecological And Economical Significance Of Protista?

They affect a wide range of industries and ecosystems. Here is the ecological and economic importance of protists.

Importance in Ecosystems

Protists play a crucial role in the food chain of ecosystems. They particularly act as producers in aquatic environments.

1. Photosynthetic protists, like algae, are partly responsible for oxygen generation.
2. They also form the base of the aquatic food pyramid.
3. Example – phytoplankton are tiny algae at the bottom of the ocean and freshwater food chains.
4. They are responsible for supporting various life forms like fish and whales.
5. Protists also play a key role in nutrient cycling.
6. They break down organic matter.
7. Then, releases nutrients that are vital for plant growth and overall ecosystem health.

What is the Economic Importance of Protista?

From an economic perspective, protists are important in many industries. These products are important in food, cosmetics, and pharmaceuticals.

1. They are used to produce products like agar, carrageenan, and alginate.
2. Growth rate and lipid content are high, making algae a promising and renewable energy source.
3. Protists are also useful in scientific research in studies related to cell biology, genetics, and evolution.

What are the Harmful Effects of Protista?

While some protists are beneficial, not all are helpful to the organisms they come into contact with.

1. Causes diseases in humans, animals, and plants, leading to economic challenges in agriculture and health.
2. Plasmodium protists cause- Malaria.

Studying and controlling these protists is advisable because they can have numerous adverse effects on society. Besides, they also offer many benefits when effectively managed.

What Diseases Are Caused by Protists?

Protists being beneficial to mankind can also prove to be fatal for humans. Protists can cause several significant diseases that can affect humans, animals, and plants. Let us discuss some well-known diseases that occur in humans, plants, and animals by protists.

Diseases Caused in Humans

Malaria

• Species of plasmodium is the famous causing agent of Malaria disease in humans.
• It is transmitted by the bite of infected Anopheles mosquitoes.
• The infected person gets fevers, chills, and anemia.

Sleeping Sickness

1. Also known as trypanosomiasis, caused by Trypanosoma brucei
2. It is transmitted by tsetse fly.
3. The nervous system is affected and its symptoms include confusion, sleep disturbance, etc.

Giardiasis

• This disease is caused by Giardia Lamblia.
• Mainly infects intestines that get transmitted through contaminated food or water.
• Occurs particularly in areas with inadequate water systems and sanitation facilities.
• Symptoms include diarrhoea, cramps, nausea, etc

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Diseases Caused in Animals

Coccidiosis

• The main disease causing agent of this disease is protozoan parasites.
• This affects animals mainly in poultry especially those which are young or have a weaker immune system.
• It spreads through contaminated food and water.
• The main symptoms are diarrhea, weight loss, and sometimes even death.

Babesiosis

1. Babesia species of protozoan parasites cause Babesiosis in animals.
2. It gets transmitted by ticks that can affect cattle, dogs, or even animals.
3. It damages red blood cells causing anaemia, jaundice, fever, or organ failure in severe cases.

Diseases Caused in Plants

Late Blight

• It is also known as potato blight or tomato blight which is caused by phytophthora protists
• Affects potatoes or tomatoes causing significant crop loss.
• Leads to water-soaked lesions on leaves, stems, or roots that cause them to rot.

Downy Mildew

• This disease is caused by water moulds like Pernospora and Plasmopara.
• Affects plant species mainly grapes, cucumbers, and lettuce.
• Causes yellowish spots and then white fluffy moulds on leaves leading to leaf drops.

FAQs on Protista

What are protists?

Protists are a basic yet well-organised kingdom of eukaryotes. Their cells consist of organelles like mitochondria that provide energy. They also contain chloroplasts for food production. They have a nucleus containing their DNA. They show locomotion via structures like flagella or cilia.

What are the characteristics of protists?

Protists have nucleated cells along with other specialised components. This includes mitochondria for energy and chloroplasts for photosynthesis. Cilia or flagella may be present to help in locomotion. Protists can survive in a variety of conditions.

What are the examples of protists?

The example of protists include algae and diatoms that come under plant like protists. Animal-like protists include amoeba, paramoecium and euglena. Whereas, different types of Slime moulds are some examples of fungus-like protists.

How do Protists reproduce?

Protists have two basic methods of reproduction. In asexual reproduction, they reproduce into two identical cells also known as binary fission. Protists can also reproduce sexually by fusing their genes.

What are the diseases caused by Protists?

Malaria, Lashmaniea, Sleeping Sickness, Giardiasis, Late Blight, Coccidiosis, Amoebiasis, etc are diseases caused by protists.