Classification of Living Things

Life Science - Middle School

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To help understand living things, scientists break them down into groups by their traits. This is called biological classification. Presently, there are eight levels of groups: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species. New discoveries in genetics may cause some regrouping of organisms and their classification over time. The three Domains ( Archaea, Eubacteria and Eukaryota) are the highest level of classification to date. They include all known living things on Earth. The Eubacteria Domain is made up of bacteria, which are single-celled living things also known as microorganisms. They are prokaryotes, lacking cell nuclei and organelles. Bacteria are found everywhere on Earth, from the soil under our feet to inside our bodies. They can cause many human illnesses, but are also vital to life on Earth. The study of microorganisms is called microbiology. The Archaea Domain also has single-celled microorganisms (prokaryotes); however, archeons can survive extreme conditions like scalding hotsprings and very salty areas. A relatively recent discovery, this domain is still being studied and updated. The Eukaryota Domain has more complex organisms with cells that have a nucleus and organelles. They are eukaryotes. This domain is currently divided into four Kingdoms: Protista, Fungi, Plantae, Animalia. The Protista Kingdom is a diverse group, including plant-like algae, animal-like protozoans and fungi-like slime molds. The Fungi Kingdom includes mushrooms, yeasts and molds. They are important detritivores, which break down dead organisms and recycle nutrients back into the environment. They can also cause problems when they invade an organism as a fungal infection, like athlete’s foot. They are extremely important to humans, as the source of penicillin, which kills bacteria, and the source of yeast, which drives useful processes like fermentation and rising bread. The Plant Kingdom includes trees, shrubs, flowers, grasses, ferns and mosses. This group is essential to all life on Earth, because they can make their own food using sunlight through the process of photosynthesis. Plants are the primary producers which feed all animal life, including us. They also absorb carbon dioxide and produce life-giving oxygen. The Animal Kingdom includes nine groups or Phyla (plural of phylum): Annelida - segmented worms Nematoda - round worms Platyhelminthes - flat worms Arthropoda - insects, spiders Porifera - sponges Cnidaria - coral, jellyfish Echinodermata - starfish, sea urchins Mollusca - snails, slugs, clams, squid, octopi Chordata - mammals, birds, reptiles, fish, amphibians Classification of Living Things
94-4021 Classification of Living Things To help understand living things, scientists break them down into groups by their traits. This is called biological classification. Presently, there are eight levels of groups: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species. New discoveries in genetics may cause some regrouping of organisms and their classification over time. The three Domains ( Archaea, Eubacteria and Eukaryota) are the highest level of classification to date. They include all known living things on Earth. The Eubacteria Domain is made up of ______________________________ which are single-celled living things, also known as microorganisms. They are prokaryotes, lacking cell nuclei and organelles. Bacteria are found everywhere on Earth from the soil under our feet to inside our bodies. They can cause many human illnesses, but are also vital to life on Earth. The study of microorganisms is called microbiology. The Archaea Domain also has ___________________-celled microorganisms (prokaryotes); however, archeons can survive extreme conditions. The Eukaryota Domain has more complex organisms with cells that have a __________________________ and organelles. This domain is currently divided into four Kingdoms: Protista, Fungi, Plantae, Animalia. The ______________________ Kingdom is a diverse group, including plant-like _____________________ animal-like protozoans and fungi-like slime molds. The Fungi Kingdom has mushrooms, _______________________ and _______________________. They are detritivores, which break down _______________ organisms and recycle nutrients back into the environment. They are extremely important to humans, as the source of _______________________, which kills bacteria, and the source of yeast, which drives useful processes like fermentation and rising bread. The Plant Kingdom includes trees, shrubs, flowers, grasses, ferns and mosses. This group is essential to all life on Earth, because they can make their own food, using sunlight through the process of ________________________________. Plants are the primary producers which feed all animal life, including us. They also absorb ___________________________ and produce life-giving ____________________. The Animal Kingdom includes nine groups or Phyla: Annelida - segmented ______________ Nematoda - round ______________ Platyhelminthes - ____________ worms Arthropoda - _______________, spiders Porifera - _________________ Cnidaria - coral, __________________ Echinodermata - __________________, sea urchins Mollusca - _____________, _____________, ______________, squid, octopi Chordata - ____________________, ______________, ______________, __________, amphibians