Plants, animals and fungi are evolutionary related in the eukaryotes (Protista). A kingdom of life containing plant-like, animal-;like, and fungi like protists. Basically they evolved differentiating within these mostly unicellular kingdom of Eukaryotes.
The following is from a Science 101 study lesson plan for senior high school students. When I was in school it was not covered until college, and not as detailed as in today's texts.
The Evolution of Protists: Importance & Evolutionary History - Video & Lesson Transcript | Study.com
Characteristics of Protists
The cellular structure of protists
"You know the basics of what plants, animals, and fungi are, but what about those eukaryotic organisms that don't quite fit within these groups? Within our system of classification, these organisms fall into the Protista kingdom. Protists are eukaryotic, mostly unicellular, and mostly aquatic. 'Eukaryotic' means that they have cells with a nucleus and membrane-bound organelles and are similar to the cells that make up our bodies. Because they are eukaryotic, protists fall within the domain Eukarya. Most protists are unicellular, meaning they are only made of one cell. However, some protists are multicellular and are made of more than one cell. Most are aquatic, meaning that they live in the water.
Types of Protists
Protists are broken up into three main groups based on how similar they are to other eukaryotic kingdoms. The three groups are animal-like, plant-like, and fungus-like protists.
Animal-like protists are
heterotrophs and get their nutrients by ingesting food, which is how animals, who are also heterotrophs, get their nutrients and energy. Animal-like protists are also called 'protozoa,' which means 'first animals.'
Plant-like protists are autotrophs and get their nutrients by performing photosynthesis, which is a process that uses sunlight to make sugars and oxygen and is also performed by plants to make nutrients and energy. Plant-like protists are also called 'protophyta,' which means 'first plants.'
The third group, the fungus-like protists, are also heterotrophs and get their nutrients by absorbing food. Now, this may seem a bit unusual, but this is how fungi get their nutrients and energy. Rather than eating food and then digesting it like animals and protozoa, fungus and fungus-like protists externally digest food and then absorb the nutrients."
More to follow . . .
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