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- Protists are a group of loosely connected, mostly unicellular eukaryotic organisms that are not plants, animals or fungi.
biologydictionary.net › protistProtist - Definition, Types and Examples | Biology Dictionary
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- Evolutionary Relationships. In the phylogenetic tree above (Figure \(\PageIndex{1}\)), protists do not share a common ancestry. Slime molds share a more recent evolutionary history with fungi and animals, while red and green algae are more closely related to land plants than they are to the brown algae (located in the Stramenopiles group).
- Cell Structure. The cells of protists are among the most elaborate of all cells. Most protists are microscopic and unicellular, but some true multicellular forms exist (such as in the brown algae, Phaeophyta).
- Metabolism. Protists exhibit many forms of nutrition and may be aerobic or anaerobic. Protists that store energy by photosynthesis belong to a group of photoautotrophs and are characterized by the presence of chloroplasts.
- Motility. The majority of protists are motile, but different types of protists have evolved varied modes of movement (Figure \(\PageIndex{3}\)). Some protists have one or more flagella, which they rotate or whip.
- Protist Definition
- History of Classification
- Characteristics of Protists
- Types of Protists
- Examples of Protists
- Related Biology Terms
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Protists are a group of loosely connected, mostly unicellular eukaryotic organisms that are not plants, animals or fungi. There is no single feature such as evolutionary history or morphology common to all these organisms and they are unofficially placed under a separate kingdom called Protista. Therefore, protists are no longer a formal classifica...
Protists include a remarkable number and variety of living organisms that far outnumber bacteria and viruses in their species diversity. It is estimated that there are nearly three times as many undiscovered protists as there are ones that have been described. Their functional diversity and the cosmopolitan nature of the niches they inhabit make th...
Protists show a wide variety of feeding habits, reproductive cycles and modes of locomotion. Some are autotrophs, using pigments to harness solar energy and convert it into simple carbohydrates. Some others are heterotrophs like amoeba and consume other organisms for food. However, many of them have been known to switch feeding modes from autotroph...
Protists can be classified based on their shape, size, the nature and number of nuclear structures, cytoplasmic organelles, presence of endo- or ectoskeletal structures and so on. Given their nature and diversity, however, informal classification is often based on nutrition and motility.
Protists are diverse and exist in a variety of ecosystems, often forming the base of the energy pyramid – as either producers or primary consumers.
Algae– Large group of loosely related photosynthetic eukaryotes found mostly in aquatic environments.Endosymbionts– Organisms that live inside the cells of other organisms and share a symbiotic relationship with the host. Mitochondria and chloroplasts are considered ancient endosymbionts.Meiosis– A type of cell division that leads to four gamete cells, each having half the chromosomes of the parent cell. Prerequisite for sexual reproduction.Phylogenetics– Study of evolutionary history and linkages between different species.1. Which of these features are found in all protists? A. Microscopic size B. Sexual reproduction C. Well-defined nucleus D.Autotrophy 2. Why is the giant kelp not considered a plant? A. Present in the ocean B. Too large C. Does not support other living organisms D.Does not have tissue-level organization of cells 3. Earliest classification of protis...
Sep 22, 2021 · The cells of protists are among the most elaborate of all cells. Most protists are microscopic and unicellular, but some true multicellular forms exist. A few protists live as colonies that behave in some ways as a group of free-living cells and in other ways as a multicellular organism.
Nov 13, 2008 · Strangely, however, the entrainment of single-celled eukaryotic organisms (the protists) into this explosive growth of research activity has lagged behind that of other microbes despite their...
- David A Caron, Alexandra Z Worden, Peter D Countway, Elif Demir, Karla B Heidelberg
- 2009
A protist ( / ˈproʊtɪst / PROH-tist) or protoctist is any eukaryotic organism that is not an animal, land plant, or fungus. Protists do not form a natural group, or clade, but are a polyphyletic grouping of several independent clades that evolved from the last eukaryotic common ancestor .
Not all protists are microscopic and single-celled; there exist some very large multicellular species, such as the kelps. During the past two decades, the field of molecular genetics has demonstrated that some protists are more related to animals, plants, or fungi than they are to other protists.
The cells of protists are among the most elaborate of all cells. Most protists are microscopic and unicellular, but some true multicellular forms exist. A few protists live as colonies that behave in some ways as a group of free-living cells and in other ways as a multicellular organism.
