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Story of classification

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1 Story of classification

2 Do you know what the word "classification" means?
It is a scientific grouping of plants and animals and fungi based on their similarities. Billions of years of evolution on Earth have resulted in a huge variety of different type of organisms. For more than two thousand years, humans have been trying to organize this great diversity of life. There are millions of different species living today, and these represent a tiny fraction of all the species that existed in the past. Classification helps to better understand the world around us and better understand the relationships between organisms. Early classification systems probably grouped organisms as to whether they were beneficial or harmful. Another ancient classification system recognized 5 animal groups - domestic animals, wild animals, creeping animals, flying animals, and sea animals.

3 Early start Until the great ages of exploration people had no idea people of the immense variety of plants and animals that shared this planet with us. To fully understand the classification of organisms you need to understand how it began. Aristotle, a philosopher and scientist who lived in ancient Greece, formed one of the first scientific classification system. This system was used for more than 2,000 years. Aristotle's system was a good start. However, it was not perfect as more organisms were discovered Aristotle's classification system became more and more disorganized. For example, penguins live in the water, like fish. However, penguins have wings and feathers, not fins and scales. Today, penguins are classified as birds, even though they cannot fly. Although this was a good attempt on Aristotle's part, it simply was not accurate enough in classifying to show relationships in species.

4 In the Air In the Water On Land *4th century BC (384 to322 BC) *Greek philosopher  *divided organisms into 2 groups - plants and animals *divided animals into blood and bloodless *also divided animals into 3 groups according to how they moved - walking, flying, or swimming (land, air, or water) *his system was used into the 1600's DISCUSSION QUESTION - Using Aristotle's 3-group system (based on movement), name 2 animals that would fit each of the 3 groups.

5 classified plants and animals according to similarities in form
CAROLUS LINNAEUS - 18th century Swedish scientist classified plants and animals according to similarities in form divided living things into one of two "kingdoms" - plant and animal kingdoms divided each of the kingdoms into smaller groups called "genera„ (plural of "genus") divided each genera into smaller groups called "species" designed a system of naming organisms called binomial ("two names") nomenclature ("system of naming") which gave each organism 2 names -genus (plural = genera) and species (plural = species) names. The genus and species names would be similar to your first and last names. Genus is always capitalized while species is never capitalized. To be written correctly, the scientific name must be either underlined or written in italics. his classification system is still used today; however, we use a 5 kingdom system (instead of 2 kingdom system.)

6 Based on Carolus Linnaeus binomial nomenclature system, each organism is given a 2-part scientific name. An organism may have more than one common name, but will only have one scientific name. example is the small, terrestrial crustacean which rolls up into a ball when disturbed. It is commonly known as an isopod, a pillbug, a sowbug, a roly-poly or a sow's ear. However. its scientific name is Armadillium vulgare ( gömbászka)

7 At the time Linnaeus developed his system of classification, people believed that species never change. The Theory of Evolution changed the way biologists thought about classification. Today's system of classification considers the evolutionary history of a species when classifying an organism. The Linnaean system of classification consists of a hierarchy of groupings, called taxa (singular, taxon). Taxa range from the kingdom to the species. The kingdom is the largest and most inclusive grouping. It consists of organisms that share just a few basic similarities. Examples are the plant and animal kingdoms. The species is the smallest and most exclusive grouping. It consists of organisms that are similar enough to produce fertile offspring together. Closely related species are grouped together in a genus.

8 This was not always the case.
We know now that organisms are classified into 7 levels. The kingdom level is the broadest and contains the largest number of organisms. All organisms are presently divided into 5 kingdoms - Monera, Protista, Fungi, Plantae, and Animalia. This was not always the case. In Aristotle's time, remember that living things were classified as either plants or animals. This 2 kingdom classification system was also used by Linnaeus and other scientists through the middle of the twentieth century. DISCUSSION QUESTION - Why did it take so long to move from a 2-kingdom to a 5-kingdom classification system (or why were all living things considered only plants or animals for so long...)? Today, a 5-kingdom classification system is generally accepted. It was proposed by R. H. Whittaker in However, this may not be the end of the story. Some scientists have proposed that organisms be divided into even more (maybe as many as 8) kingdoms! Viruses are not included in any of the present 5 kingdoms - mainly due to their many nonliving characteristics (for example, viruses are not cells). Bacteria may eventually be divided into more than just the one kingdom Monera because there are some very different groups of bacteria. Algae pose an entirely different problem. Earlier classification schemes classified algae as plants. However, current schemes include the unicellular algae within the kingdom Protista, while keeping the multicellular algae within the plant kingdom. Classification is a constantly changing, dynamic science! This means that you can still learn by discovery, not just memorization!

9 KINGDOM MONERA (monerans) -
*1 cell *no true nucleus - prokaryote (genetic material scattered and not enclosed by a membrane) *some move (flagellum); others don't *some make their own food (autotrophic); others can't make their own food (heterotrophic) *examples - bacteria, blue-green bacteria (cyanobacteria) KINGDOM PROTISTA (protists) - *1 cell *have a true nucleus - eukaryote *some move (cilia, flagella, pseudopodia); others don't *some are autotrophic; others are heterotrophic  *examples - amoeba, diatom, euglena, paramecium, some algae (unicellular), etc KINGDOM FUNGI - *multicellular  *have nuclei *mainly do not move from place to place *heterotrophic (food is digested outside of fungus) *examples - mushroom, mold, puffball, shelf/bracket fungus, yeast, etc.

10 KINGDOM PLANTAE (plants) -
*multicellular *have nuclei *do not move  *autotrophic *examples - multicellular algae, mosses, ferns, flowering plants (dandelions, roses, etc.), trees, etc KINGDOM ANIMALIA (animals) - *multicellular *have nuclei *do move  *heterotrophic *examples - sponge, jellyfish, insect, fish, frog, reptiles, bird,mammals, man DISCUSSION QUESTION - For a long time, fungi (mushrooms, etc.) were classified in the plant kingdom. Eventually, they were placed into their own kingdom (Kingdom Fungi). List some reasons that they are similar to plants. Then list some reasons that they are different from plants.

11 Evolution has taken place over millions of years and scientists believe this is the reason why all l living things on Earth exist today. There are different views and theories about the origin of life and the evolutionary process. English naturalist Charles Darwin wrote one of the first major scientific books on this subject. Charles Darwin Charles Darwin ( ) Charles Darwin was an English naturalist who studied variation in plants and animals during a five-year voyage around the world in the 19th century. He explained his ideas on evolution in a book called, 'On the Origin of Species', published in This shows how species adapt and change by: variation – in any population of organisms there will be some differences over-production – many organisms produce more offspring than necessary struggle for existence – there is competition for survival and resources between the organisms survival - those with helpful characteristics are more likely to survive to breed useful characteristics inherited by the offspring gradual change of the species over a period of time as useful characteristics are passed to offspring.

12 Darwin's ideas caused a lot of controversy, and this continues today, because they can be seen as conflicting with religious views about the creation of the world and the creatures living in it. The basic idea behind the theory of evolution is that all the different species have evolved from simple life forms. These simple life forms first developed more than 3 billion years ago (the Earth is about 4.5 billion years old). The timeline below shows some of the key events in the evolution of life on Earth, from the first bacteria to the first modern humans.

13 http://www. sciencechannel

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