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Classification of Living Things

Why do we classify things? Supermarket aisles Libraries Classes Teams/sports Members of a family Roads Cities Money

Why classify things? Say you go to the mall to get some new clothes. Where would you go? How would you know to go to that particular store?

How is a mall organized? Food Court Specialty Clothing Stores Jewelry Stores Electronics Stores Shoe Stores Toy Stores

Can you imagine if the mall was just one big store and you had to go through rows and rows of “stuff” to find the right clothes in the right brand and the right size for you? How long would that take?

Big Idea: The mall, your city, your school, and your closet (hopefully) are all organized so that you and other people can get things done without wasting extra time and effort. Scientists also organize or classify things so that they are easier to investigate and understand.

Here are some things that scientists classify or organize: The elements The human body Interactions in Ecosystems

Early classification Aristotle grouped everything into simple groups such as animals or plants He then grouped animals according to if they had blood or didn’t have blood, and if they had live young or laid eggs, and so on…

Binomial Nomenclature Developed by Carolus Linnaeus Swedish Biologist 1700’s Two-name system Genus and species named using Latin or Greek words

Rules used to write scientific names Homo sapiens An organism’s genus is always written first; the organism’s species is always written second The genus is Capitalized; the species is written in lower case Scientific names of organisms are always italicized or underlined

The modern system of classification has 8 levels: Order Family Genus Species Domain Kingdom Phylum Class

Basic Classification Domains: Archaea There are three Domains of living organisms based on their characteristics: Archaea (also called Archaebacteria) Eubacteria (also called Bacteria) Eukaryota (also called Eukarya) Eubacteria Eukaryota

Basic Classification Kingdoms: The Domains can also be split into Kingdoms which further divide the organisms by their characteristics.

Autotrophic or heterotrophic Domain Archaea Aerial view of hot spring at Yellowstone “Archaea” means “ancient” bacteria. Organisms in Archaea are: Unicellular Prokaryotic Autotrophic or heterotrophic Organisms that reproduce asexually Bacteria that have adapted to extreme environments. Some can survive in extremely hot environments, like around hot springs and geysers. They are called thermophiles. Some can survive in extremely salty environments, like The Great Salt Lake in Utah. They are called halophiles. The Domain Archaea has one Kingdom, also called Archaea

This hot spring is flowing into the Firehole River in Yellowstone This hot spring is flowing into the Firehole River in Yellowstone. The colors are caused by different varieties of archaebacteria and other microscopic life forms. Scientists can distinguish temperatures of water by the colors present.

Domain Eubacteria Many are common infectious agents. “Eu” means “true” bacteria. They are: Unicellular Prokaryotic Autotrophic or heterotrophic Organisms that reproduce asexually The most abundant organisms on earth. One bacterium can give rise to 10 million in 24 hours. Found in almost every habitat on earth. The Domain Eubacteria has one Kingdom, also called Eubacteria. Many are common infectious agents.

This is a picture of bacteria on the skin This is a picture of bacteria on the skin. Bacteria can be shaped like a sphere (cocci) like this picture, like a rod, or like a spiral. The structure in the middle of this picture is a hair follicle with a hair growing out of it.

Nucleus and Organelles Terminology: The Domains Archaea and Eubacteria are commonly grouped together in discussion and called prokaryotes because they lack membrane-bound nuclei and membrane-bound organelles. Nucleus and Organelles

Domain Eukaryota (Eukarya) Eukaryotic Very diverse Unicellular or multicellular Autotrophic or heterotrophic Reproduce sexually or asexually Can be split into 4 Kingdoms- Protista Fungi Plantae Animalia

The 4 Kingdoms in Eukaryota Protista Mostly unicellular and microscopic Autotrophic or heterotrophic Can be infectious agents Examples: Amoeba Algae Daphnia Plasmodium (causes malaria) Plantae Multicellular green plants Autotrophic through photosynthesis Have a cell wall Mosses Ferns Trees Flowering Plants Fungi Multicellular Heterotrophic Decomposers Mushrooms Athlete’s foot Bread Mold Animalia Multicellular Animals No Cell Wall Insects Spiders Crabs Birds Humans

D O M A I N S K I N G D O M S

Think Break: Where do Viruses fit in this classification system? Are Viruses Alive? http://serc.carleton.edu/microbelife/yellowstone/viruslive.html http://cvr.bio.uci.edu/downloads/Scientific_Amer.pdf Are Prions Alive? http://scitechstory.com/2009/12/31/prions-not-alive-but-they-can-evolve/

How would you classify these? A organism that can exist in extremely hot temperatures and that is made of only one cell with no nucleus Domain: Archaea Kingdom: Archaea A green organism growing from the ground that is multicellular and that undergoes photosynthesis; its cells have nuclei and cell walls Domain: Eukaryota Kingdom: Plantae

Try two more: This microscopic and one-celled organism lives in colonies with millions of others like it. It does not have a nucleus and cannot survive in extreme conditions. It could be an infectious agent. Domain: Eubacteria Kingdom: Eubacteria This organism is a multicellular decomposer; its cells have nuclei. Domain: Eukaryota Kingdom: Fungi

Classification Systems Can Change! Can you guess why? Classification systems change as new organisms are discovered and as more information is gained about known living organisms. Science is a “work in progress” and things change as new evidence is found. There is a great amount of debate over the current classification system, especially the classification of the types of bacteria and whether viruses are alive or not.

Which one would you choose? Why? Even though classification is not an exact science, it is a part of almost every aspect of our lives. This is an example of classifying by personal preference which all students have experience with. Which one would you choose? Why?

Quick, organize these living things into groups:

Did you do it like this? These are grouped by color: Blue, red or red and blue

Are there any other ways to group these living things? Or this? These are grouped by type of organisms: Fish, butterfly or bird This is probably a more meaningful way to group these for scientific purposes than the previous slide’s grouping by color. Are there any other ways to group these living things?

Classify these organisms