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Characteristics and groups of living things
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All living things share eight characteristics. Scientists sort eukaryotic organisms into plants, animals, fungi and protoctists.
Eight characteristics of life
Living organisms:
require nutrition, respire, excrete their waste, respond to their surroundings, move, control their internal conditions, reproduce, and grow and develop.
require nutrition, respire, excrete their waste, respond to their surroundings, move, control their internal conditions, reproduce, and grow and develop.
Plants and animals
Fungi and protoctists
Fungi cannot photosynthesise. Most have a body called a mycelium, made of thread-like hyphae that contain many nuclei. Some, like yeast, are single-celled. Their cell walls are made of chitin. They feed by saprotrophic nutrition: they secrete digestive enzymes onto food outside the body and absorb the small molecules. They store carbohydrate as glycogen. Examples: *Mucor* and yeast.
Protoctists are microscopic single-celled organisms. Some are like animal cells (*Amoeba*), some have chloroplasts like plants (*Chlorella*), and some are pathogens (*Plasmodium*, which causes malaria).
Protoctists are microscopic single-celled organisms. Some are like animal cells (*Amoeba*), some have chloroplasts like plants (*Chlorella*), and some are pathogens (*Plasmodium*, which causes malaria).
A single-celled organism lives in pond water. It has chloroplasts but it is not a plant. Which group does it belong to?
- It is single-celled and microscopic.
- It has chloroplasts, so it is like a plant cell, but plants are multicellular.
- Microscopic single-celled organisms like this are protoctists, for example Chlorella.
Answer: Protoctists
Living things need nutrition, respire, excrete, respond, move, control internal conditions, reproduce and grow. Plants have chloroplasts and cellulose walls and store starch. Animals store glycogen. Fungi have chitin walls, hyphae and saprotrophic nutrition. Protoctists are single-celled.
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