Classifying living things

1. Classifying living things • Scientists develop system for classifying living things. • Scientists classify millions of species • 400 years ago organisms were classified on their appearance and behavior • The problem with this is scientists have realized that appearances can suggest false connections. • Many things helped change these classifications • Observing • Collecting samples • The microscope

2. Classifying living things • Classification and Taxonomy • Classification is the process of arranging organisms into groups based on similarities • Taxonomy is the science of naming and classifying organisms. • A good system allows one to organize a large amount of information • so it is easy to find and understand.

3. Classifying living things • Using Classification • Similarities and differences among species are used • Sometimes easy to see like fur, feathers, or scales • Others more detailed and require DNA • Taxonomists study Biological relationships • The Greek word, taxis means arrangement. • Taxonomists are scientists who classify and name organisms based on their similarities and differences.

4. Classifying living things • A Taxon is a group of organisms that share certain traits. • Taxons can be broad like animals and plants • More specific like cats and roses. • Taxonomists try to discover how one species evolved as compared with another species. • Species sharing an ancestor are group together.

5. Classifying living things • To determine how to classify, scientists compare a variety of characteristics or traits • A trait is a characteristic or behavior that can be used to tell two species apart. • IF two organisms share a trait, taxonomists try to determine if they share the trait because they share an ancestor.

6. Classifying living things • Physical Evidence • All physical evidence helps scientists see that all living organisms are related by evolution • Primary tools used • Color • Size • Weight • How group of organisms obtain energy. • The internal structure • And outward appearance • Comparing skeletons, and fossilized parts

7. Classifying living things • Genetic Evidence • In the mid 1950’s DNA helped further classify • Genetic evidence usually support physical evidence, but not always • Best example is the red panda and Panda bear • Both ate bamboo, • Both look alike except for size • DNA proved that the red panda is more related to the raccoon family • Pandas more closely to bears

8. Classifying living things • Biologists use seven levels of classification • Carolus Linnaeus developed both a naming system and how to organize them. • Used appearance to group • This was called the binomial nomenclature. • Binomial means two names • Nomenclature means list of names • Most of these names are Latin

9. Classifying living things • Using scientific names • He used both a genus and species. • Certain rules for scientific names must be followed • First letter of the genus (which comes first) is capitalized • Species’ first letter is lowercase • Both written in italics • These two names are part of a classification system that contains several larger parts.

10. BINOMIAL NOMENCLATURE • Uses two names • A GENUS and A SPECIES • Haliaeetus leucocephalus • Genus is always CAPITALIZED • Species is always lower case • BOTH ARE IN ITALICS OR UNDERLINED • Just like us, each animal was given 2 names

11. Canis latrans Coyote Canis lupis Timber Wolf Canis familiaris Domesticated Dog Panthera leo Lion Panthera onca Jaguar Latin Binomials

12. Classifying living things • Classified into 7 groups • Each group gets narrower or specific then that last. • Kingdom (most general) (Animalia- the animals) • Phylum (Chordata- animals with a backbone) • Class ( Mammalia- mammals or furry animals that nurse their young.)

13. Classifying living things • Order ( Carnivora- carnivores, or animals that kill and each other animals) • Family (Felidae- cat family) • Genus( Felis housecats, cougars, and many others • Species (catus- all housecats regardless of breed) • Scientists can compare very broad categories, • As they go down the classification level, you get more specific, eliminating organism that are not longer similar.

14. Classifying living things • Dichotomous keys and field guides help identify • A series of questions that can be answered in only 2 ways • Your answer to each question leads to another question with only 2 choices • The questions gradually narrow down the list of possible organisms. • Field guides also help identify based on physical characteristics.

15. Classifying living things • Classification systems change as more is learned. • Taxonomy changes as discoveries are made • First there were 2 groups • Plants • Green • Non-moving • Animals

16. Classifying living things • Three Domains • Grouping before placing organism into Kingdoms • Cells containing a nucleus are called eukaryotic cells • Cells with no nucleus called prokaryotic cells • The domain Bacteria and Archae include ONLY prokaryotic cells • Eukarya contain organisms with eukaryotic.

17. Classifying living things • Bacteria- class smaller then Eukarya and have no nucleus • Archaea- Cells have a distinctive chemistry and can survive extreme environments. • Eukarya- larger and contain more complex structures

18. Classifying living things • Six Kingdoms • After domains, all organisms fall into one of six kingdoms • Plantae (includes plants, trees, grass, and moss) • Animalia (animals from lions to bugs to Multicellular microbes) • Protista ( organisms that don’t fit easily into animals, plant, or fungi. Either unicellular or have a simple Multicellular structure)

19. Classifying living things • Fungi (mushrooms, molds and yeasts) • Archaea ( organisms that are similar to bacteria but have a cell structure so different they must fit in own kingdom) • Bacteria (unicellular with no nucleus) • Changed around 1990 from 5 kingdoms. • Chemical differences between cells • Protista should be arranged into smaller kingdoms because of the many differences among its species.

20. Classifying living things • Two most familiar kingdoms are plants and animals. • Plantae • 250,000 plant species known on Earth. • Tiny moss to giant kelp • All plants multicellular • All plants can make their own food via photosynthesis • Can not move from place to place • Can turn to face the sun or light • Grow upward

21. Classifying living things • Animalia • Already a million species in the kingdom • More then 90 percent are insects • All animals get energy from other organisms • Most have some type of mouth and • A nervous system • Has no cell wall like plants

22. Classifying living things • Other organisms in remaining 4 kingdoms • Protista • Has a wide variety of organism • Most unicellular • Have large complex cells with true nucleus (eukaryote) • Some eat other organisms • Some can photosynthesize • Do not have specialized cells like plants, animals, or fungi • Most live in fresh or salt water Euglena sp.

23. Classifying living things • Some organisms, like seaweed are also classified as Protista • Fungi • Composed of molds, yeasts, mushrooms • Take in nutrients from their surrounding • Remain rooted in one place • Many fungi act as decomposers • Don’t photosynthesize

24. Classifying living things • Archaea • Mid 1990’s changed classification of bacteria • Do not have a nuclei • But cell structure is different from that of bacteria • Live in water environments • Live in extreme environments like boiling mud near geysers, Hot vents, bottom of oceans, salt ponds, deep in sand

25. Classifying living things • Bacteria • Live just about everywhere. • Most are helpful • Some harmful • All unicellular • Have small cells without a nucleus • Have a cell wall but not the same as plants