Dallas Zoological Society Partnership : Middle School Lessons

Classifying Animal Life

WebLesson Sites
Life is all around us. Your house is filled with living things- your family, your pets, and millions of living things you can’t even see that live on your skin, inside your body, even in your carpet! It is the task of biologists to study all life on the planet. And just like with people, it is much easier to describe and explain something or someone if it has a name.
Taxonomy is the branch of biology that is concerned with classification of living things. Taxonomists study all different forms of life and look for similarities and differences in order to put them in groups. The groups start out large with many different organisms that have only a few things in common, and then the organisms are sorted into smaller and smaller groups until a single species has been identified and named. In today’s lesson, you will be learning more about the classification system biologists use and the different groups of life scientists have identified.
Lesson Pages
Conclusion & Project
All life that has been currently identified and studied is placed into one of six kingdoms. Single-celled Eubacteria are found in every imaginable environment. Humans depend on bacteria, but are also affected by them with many diseases. Even older and smaller than Eubacteria are the Archaebacteria, primitive life forms living in only the most extreme environments on the planet. The primary difference between these two kingdoms and the other four is based upon cell structure. Plants, animals, fungi, and protists all have a nucleus in their cells, whereas bacteria do not. These life forms also tend to be more complex, with those that consist of more than one cell organizing themselves into tissues, organs, and organ systems. All of these kingdoms contain millions of species and represent the vast biodiversity of our planet.
You are a scientist working at NASA. Your team has made contact with an alien life form. It is your job to explain to the alien what “life” is on planet Earth. Use the facts of the lesson to write a report on how life is defined and classified on Earth and describe the different types of life forms on the planet.
RNA - chemical similar to DNA from which proteins are made
amniotic egg - egg of reptiles and birds that contain amnion, a membranous sac that surrounds and protects the embryo
annelid - worms with bodies divided into cylindrical rings
autotroph - organism that can make its own food (usually using sunlight)
binary fission - equal division of a single-celled organism into two organisms
cell wall - outer layer of some bacteria that is exposed to the outside environment
chitin - carbohydrate that forms the exoskeletons of insects and other invertebrates
cladistics - classification system based on the order of evolutionary branching rather than on present similarities and differences
endocrine - system of the human body that releases hormones
heterotroph - organism that is not capable of making its own food
hierarchy - series of ordered groupings moving from broader general categories to narrow specific ones
hydrothermal vent - place on the ocean floor where hot, chemical-filled water flows up through cracks in the Earth's crust
inclusive - including much or everything
integumentary - having to do with skin, hair, and nails
marsupial - mammal that gives birth to under-developed young and rears them in a pouch
mineral - compound occurring naturally in the earth's crust
nucleus - part of the cell containing DNA
organelle - organized structure within a cell with a specific function
ovary - female reproductive organ that produces egg cells
protoplasm - living substance of a cell
spore - reproductive cell
stimulus - something that causes a response