They are less complex
The first eukaryotic organisms on earth were likely single-celled organisms such as protists, which are a diverse group of organisms that have a nucleus and other membrane-bound organelles. These organisms are thought to have evolved around 1.6-2.1 billion years ago.
Protists type of organisms are either all eukaryotes or there are some who are not
Prokaryote
Eukaryotic, they have an enclosed nucleus and membrane bound organelles. They are generally single cellular. However, it is important to know that when they form multicellular colonies the cells do not specialize as in other eukaryotes.
The one unifying characteristic of protists is that they are eukaryotic organisms, meaning their cells contain a nucleus and other membrane-bound organelles. This sets them apart from prokaryotic organisms like bacteria.
The four kingdoms that contain eukaryotic organisms are Animalia (animals), Plantae (plants), Fungi (fungi), and Protista (protists). These organisms have cells with a nucleus and other membrane-bound organelles.
Protists are a diverse group of eukaryotic organisms that do not fit into other kingdoms like plants, animals, or fungi. They can be unicellular or multicellular and exhibit a wide range of forms and lifestyles. Protists play various ecological roles, from being photoautotrophs to predators, parasites, and saprobes.
All protists are eukaryotic (have a nucleus), most live in water. They are the "ancestor organisms" because they were the first organisms ever to exist.Protists are simply organisms that don't fit into any of the other kingdoms.The great diversity of form, habitat, mode of nutrition, and life history exhibited by eukaryotes suggests they evolved several times from various groups of prokaryotes. This makes the Protista a polyphyletic group. Eukaryotes are generally larger, have a variety of membrane-bound organelles, greater internal complexity than prokaryotic cells, and has a secialized method of cell division (meiosis) that is a prelude to true sexual reproduction. Protists might be viewed as a group from which the other eukaryotic kingdoms evolved.
Dinoflagellates are eukaryotic organisms. They are single-celled protists that belong to the domain Eukarya, which includes all organisms with cells that have a distinct nucleus and other membrane-bound organelles.
It means that protists are organisms that have a cell or cells with a true nucleus and other membrane-bound organelles. This distinguishes them from prokaryotes, which lack a nucleus and other organelles. Eukaryotic organisms also include animals, plants, and fungi.
One-celled animal-like protists are known as protozoa. They are eukaryotic organisms that can move and obtain their food through various means, such as engulfing other organisms or absorbing nutrients from their surroundings. Examples include amoebas, paramecia, and flagellates.
No, protozoans are a type of animal-like protists. Protozoans are consumers that can live in water, soil, or other organisms. While these organisms do not resemble animals, they are called animal-like because they are consumers and they share some characteristics with animals. Other types of protists are plantlike and fungus-like protists.