Classification of Organisms Chapter 18

Why Classify? Biologists use classification to organize living things into groups so that the organisms are easier to study. 2

For Example These organisms have been classified by their color. Red Green 3

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One Possible Solution Animals Plants ???? 5

Our modern classification system originated with two main classifications, plants and animals. Over the years, scientist came up with certain “plants” that really did not act like plants, they couldn’t make their own food. So the kingdom Fungi was formed. 6

This lead to the creation of the Kingdom Protista. When microscopes were invented, scientists discovered new single celled organisms. Some were animal-like, some were plant like and some were both. This lead to the creation of the Kingdom Protista. 7

As the microscope improved, scientists discovered that many of the single celled organisms were quite different. Some of them had a nucleus and others did not. This lead to the Kingdom Monera, the kingdom of the most simplistic organisms, Bacteria. 8

Taxonomy- The study of how living things are classified Asistotle – he had the first classification system that group animal according to how the moved or where they lived. Swim Fly Walk /crawl He also had subgroups for organisms that shared other characteristics Carolus Linnaeus (1730s)- Swedish – He placed organisms in groups according to observable features and physical characteristics. 9

Linnaeus’s Naming System Linnaeus had a two name system called Binomial Nomenclature Felis concolor is the scientific name for a puma. Felis Is the genus name- it is written first and is always capitalized concolor Is the species name – it is written second and is always lower case 10

Linnaeus used the Latin language because that was the language that was dominant around the world at that time. This is why even today organism’s scientific names are always in Latin. 11

Along with the two major Kingdoms, Plant and Animal, Linnaeus came up with several sub-classifications for those kingdoms. They are: Kingdom, Phylum, Class, Order Family, Genus, and Species. What Kingdom are you in? What phylum are you in? Why? 12

Levels of classification Kingdom Phylum Class Order Family Genus Species Kindly Pay Cash Or Furnish Good Security 13

The Human Species Kingdom: Animalia (Animal in Latin) Phylum: Class: Order: Family: Genus: Species: Animalia (Animal in Latin) Chordata (Spinal Cord) Mammalia (have mammary glands) Primates (two mammary glands) Hominoidea (bipedal) Homo Sapiens 14

Homo sapiens When you refer to an organism scientifically, you always use the genus and the specie names. Therefore, the human species would be referred to as: Homo sapiens 15

Recognizing Species Biologists usually define species based on appearance and structure Biological species- group of actually or potentially interbreeding natural populations, reproductively isolated from other such groups Hybrids can be made between two species

Evolutionary History Convergent evolution- organisms evolve similar features independently Example: anteaters- long, sticky tongue; few teeth; large salivary glands

Evolutionary History Analogous characters- similar features of organisms that evolve independently Phylogeny- evolutionary history of a species

Cladogram Cladogram- diagram based on patterns of shared, derived traits that shows the evolutionary relationships among groups of organisms

Cladogram Differences in morphological, physiological, molecular, and behavioral level between organisms New derived characters will show up on the cladogram as groups evolve

Conclusion The classification system for organisms have been around for a long time. It has endured several changes and is quite complex. Without it modern biology could not exist, much in the same way that a grocery store would go out of business if it did not have a classification system. 21