Classification Vocabulary

  • Classification - This is the process of grouping things or ideas.  We group them by looking at their similarities and their differences, and don’t group by their size, color or by what they can do.


    Living - Things made of cells doing life functions.


    Dead Things made of cells no longer doing life functions.


    Non-living Things made of atoms but do not have cells.


    Homologous Organs - Organs of two different organisms that each does a similar job for their organism. Gills of fish are homologous with our lungs because each helps take in oxygen.  A fish’s fin is homologous with a bird’s wings because each helps the organism move.


    Kingdoms- they are the largest groups that organisms (living thing) are classified into.  There are five and include: plant, animal, fungi, protist & bacteria kingdoms.


    Phylum – Subdivision of a kingdom. There is only one vertebrate phylum in the animal kingdom. The other 8 animal Phyla (plural) are invertebrates. 

    Vertebrate – An animal with an internal skeleton. (not necessarily made of bone)


    Invertebrate – An animal with an exoskeleton or no skeleton at all.


    ArthropodsThis is by far the largest animal phylum. These animals are grouped together because they all have exoskeletons, jointed legs and segmented bodies. 


    Class – It’s a subdivision of a Phylum. An example would be that crustaceans, arachnid, insects, millipedes and centipedes are the 5 classes of Arthropods. Grammy is an arachnid.


    Order – It’s a subdivision of a Class. Grammy belongs to Order Araneae.


    Family - It’s a subdivision of an Order. Grammy belongs to Family Theraphosidae.


    Genus - It’s a subdivision of a Family. Grammy belongs to Genus Grammostola.


    Species - It's a subdivision of a Genus. These are the smallest groupings for organisms.

    This group contains just the male and female of one kind of living thing. Grammy’s

    Species name is gala (Note that this name isn’t capitalized.)


    Binomial Nomenclature – It’s the 2 name, name that we call the scientific name.  It is made up of the genus and the species names. So, Grammy’s scientific name is Grammostola gala. (This is the proper format for scientific names.)


    Dichotomous Key – A tool used to classify. A series of two part questions that start with the phrase “Does it have…?” Each question asks about the presence of physical traits.


    Exoskeleton - This insect part covers the outside of the body.  It gives the body shape and it protects the animal from predators.  It is made of chitin.


    Head – Front or Anterior part of insects. Arthropod heads have compound eyes and mouthparts called mandibles. Sometimes there are antennae, but never legs or wing there.


    Thorax - It is the middle part of the insect. All of the wings and all of the legs are attached to this section only.


    Cephalothorax – This is when the head and thorax of some arthropods are together as one part. (Like Grammy)


    Abdomen - This insect part is at the Posterior end (at the rear) and it contains most of the Digestive and Reproductive organs. There are sometimes appendages on arthropod abdomen, but they never have legs on an abdomen.


    Ovipositor - It is a long tube on a female insect’s abdomen. It is used to deposit eggs.


    Spinnerets - Spiders and some moth larva have these abdomen appendages to produce web material.


    Metamorphosis - Life stages of an insect as it changes form.  There are 2 kinds in insects. Complete metamorphosis stages include: egg > larva > pupa > adult.  Stages of incomplete metamorphosis stages are: egg > nymph > adult.


    Larva - This is the caterpillar stage of metamorphosis. This is the 2nd step and is just after the egg stage.


    Pupa - It is the cocoon stage of insect (complete) metamorphosis. This is the 3rd stage and comes after the larva stage.


    Nymph - It looks like a small adult, but it can’t reproduce like an adult.


    Molting - It is the process where insects get rid of an old exoskeleton as the animal gets larger.  Birds & snakes also molt.