Lesson 2 Classification of living things.pptx

Classification of organisms

1. Classification of living things How living things are scientifically classified Lesson 2

2. BIG IDEAS D escribe the distinguishing characteristics of different groups of organisms, and use these characteristics to further classify these organisms using a classification system

3. course title There are many types of life on Earth. All living things share certain characteristics, so they all belong to one group: Organisms. Scientists believe there are over 10 million types of organisms on Earth. Classifying organisms helps scientists study them and understand them better. Classifying Organisms

4. Classification is the process of grouping things based on similarities. Classification is the placing of similar things into similar groups or organizing things based on their characteristics or on specific criteria. When objects are classified they are put into groups with other objects that have the same attributes (characteristics). CLASSIFICATION TAXONOMY The science of classifying living things is called Taxonomy.

5. Why do we need to classify living things? It makes the study of such a wide variety of organisms easy. It projects before us a good picture of all life forms at a glance. It helps to know the origin and evolution of organisms. Scientists estimate that there are up to 30 million species of organisms on Earth! If they use systems to classify these organisms they can see patterns in nature and can see how organisms relate to each other.

6. Aristotle (384 BC-322 BC) The classification of plants and animals can be traced back to Ancient Greece. Aristotle was a famous philosopher and scientist who lived 2,500 years ago and he was the first person to try and classify living things into groups. Aristotle decided there was a hierarchy of living things which he called the Ladder of Nature/Life; it ranked living things on their ability to move and sense. There were 2 major groups - plants and animals, that he called Kingdoms.

7. Linnaeus (1707-1778) In the 1700s Carl Linnaeus developed the classification system that classified organisms according to their similarities, functions and relationships with other organisms. Linnaeus was a Swedish scientist who developed a system of organizing living things. It forms the basis of the classification and naming system we use today. Today with the use of modern microscopes and genetics we can classify living organisms very accurately. In this way we are able to classify living organisms according to their shared characteristics.

8. To help scientists classify organisms, they ask themselves these questions: 1. How many cells does the organism have? 2. Is a nucleus present? 3. How does the organism obtain its energy?

9. There are three main characteristics that scientists use to classify organisms: 1) number of cells – unicellular or multicellular; 2) presence of nucleus – prokaryote or eukaryote; 3) how energy is obtained – autotroph or heterotroph;

10. Unicellular organisms

11. Euglena Take a look at this euglena. A euglena is an organism made up of a single cell. Unlike humans, it does not have specialized organs, such as a brain or stomach. However, it can move through its environment using its whip-like flagellum. It even has a primitive eye called an eyespot for sensing light levels. All this in a single cell!

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13. CELL One of the most important internal characteristics that scientists use to classify organisms is the cell. All living organisms are made up of one or more cells. A cell is the basic unit of life. Cells are surrounded by a cell membrane that keeps the cell intact. Inside all cells are specialized structures called organelles that carry out specific functions inside the cell. Organelles are suspended in a thick, gel-like fluid called cytoplasm.

14. CELL All cells also have genetic material called DNA. DNA contains the instructions for making new organisms and for carrying out all functions that keep a cell alive. In some cells, DNA is packaged inside a membrane called a nucleus. In other cells, it floats freely in the cytoplasm.

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16. There are two main types of cells: prokaryotic and eukaryotic. Scientists think prokaryotic cells were the first cells on Earth. The earliest records of prokaryotic cells date to around 4 3.8 billion years ago. Prokaryotic cells have the basic structures common to all cells. These structures include a plasma membrane surrounding cytoplasm. However, prokaryotic cells do not have membrane-enclosed organelles, such as mitochondria or a nucleus.

17. There are two main types of cells: prokaryotic and eukaryotic. Eukaryotic cells are more complex. Similar to prokaryotic cells, eukaryotic cells have a cell membrane, cytoplasm, and DNA. However, they have something that prokaryotic cells do not. Eukaryotic cells have organelles surrounded by membranes. This includes mitochondria and a nucleus, where DNA is stored. Examples of prokaryotic cells include bacteria. Eukaryotic cells include plants, animals, and fungi.

18. Prokaryotic and eukaryotic cells have other important similarities and differences. Both prokaryotic and eukaryotic cells have other things in common. Both have ribosomes in their cytoplasm. Ribosomes are responsible for making proteins in the cytoplasm. The ribosomes in eukaryotic cells are bigger and more complex than those in prokaryotic cells. However, they perform the same function of making proteins.

19. Prokaryotic and eukaryotic cells have other important similarities and differences. Prokaryotic cells tend to be much smaller than eukaryotic cells. On average, eukaryotic cells are about 10 times larger than prokaryotic cells. Eukaryotic cells have much greater diversity in shape and size than prokaryotic cells. Organisms with prokaryotic cells are so small they can be seen only through a microscope. You also need a microscope to see eukaryotic cells. However, many organisms with eukaryotic cells are large enough to see without a microscope.

20. There are two main types of cells: prokaryotic and eukaryotic.

21. (Note: Prokaryotes are organism having prokaryotic cells and Eukaryotes are organisms having Eukaryotic cells)

22. AUTOTROPHS Organisms that make their own food are called autotrophs. Auto- means “self”, and – troph means “feeder.” Therefore, an autotroph is a self-feeder. They use the food they make as an energy source to carry out their life functions. Examples are plants that make their own food by transforming the radiant energy from the Sun to chemical energy through the process of photosynthesis. Autotrophs are also known as producers. Some bacteria are autotrophs. They use chemicals in their environment to make their own food. Euglena, can make their own food. They contain a structure called a chloroplast, and they use sunlight for photosynthesis.

23. Heterotrophs Organisms that cannot make their own food are called heterotrophs. Hetero-means “other” and – troph means “feeder”. A heterotroph must feed off of others. They get their energy from eating autotrophs (plants) or eating other heterotrophs. Examples are animals, mushrooms, and molds. Euglena are able to consume food when light is not present. Heterotrophs are also known as consumers. Heterotrophs transfer the chemical energy from food into other forms of energy they can use.

24. An organism is placed into a  broad  group and is then placed into  more specific  groups based on its structures. ● The levels of classification, from broadest to most specific, include:  kingdom, phylum, class, order, family, genus, and species . course title 25 Every animal on the planet, down to the most microscopic creature you can imagine, can be classified according to this system. K eep  p onds  c lean  o r  f rogs  g et  s ick .

25. Scientific name Linnaeus designed a special naming system called the  binomial nomenclature  to name all organisms. All organisms are therefore given  two  (bi- means two) words in their name. The first part of the name refers to the genus that the organism belongs to. This is always written with a capital letter. The second part of the name refers to the species within the genus If you are typing you will put both these names in  italics  but if you are doing a handwritten piece you underline it. This shows that you are identifying the organism by its scientific name. For example, the scientific name for the African elephant is  Loxodonta africana . Humans belong to the genus  Homo  and to the species  sapiens  so we are  Homo sapiens .

26. All living organisms can be divided into five  kingdoms : course title 27

27. CHARACTERISTICS OF KINGDOM MONERA This kingdom consists of all bacteria and scientists cannot begin to estimate how many species there are. They are found everywhere as they can live anywhere, even deep within the Earth‛s crust where no other life exists. They are unicellular organisms. Prokaryotes

28. CHARACTERISTICS OF KINGDOM MONERA Some are autotrophs while others are heterotrophs. They can be rod shaped, spiral shaped or round and can have hairs or tails to help them move. They reproduce by dividing, so populations of bacteria can grow very quickly. Can be helpful or harmful. Bacteria in yogurt or your digestive system can be helpful, while bacteria that cause diseases such as E. coli or Salmonella can be harmful. Some of these bacteria are decomposers which play an important and helpful role in our ecosystem.

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33. CHARACTERISTICS OF KINGDOM PROTISTA Eukaryotes. Some are unicellular, and some are multicellular. Many of these organisms are microscopic such as Amoeba, Paramecium, and Euglena. Some are autotrophs and others are heterotrophs. Vary  in the ways they  move and obtain energy . Protists obtain their energy in several ways course title 34

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35. course title 36   Plant-like protists  produce food through photosynthesis. Red Algae Kelp

36. course title 37 Fungus-like protists  obtain their food absorb nutrients from decaying organic matter in their environment. Slime Mold

37. Animal-like protists  ingest or absorb food after capturing or trapping it. Protists have three main ways to move (locomotion) : course title 38

38. ●  Flagellum  (flagella) - a long whip-like tail used to move and/or catch food. An example of a flagellated protist is the Euglena. course title 39

39. Cilia Small hair-like projections on the surface (cell membrane) of the cell used to sweep food into mouth-like structures and/or beat them in rhythm to move. An example of a ciliated protist is a paramecium. course title 40 Paramecium under microscope

40. Pseudopod  – (false foot) A finger-like projection of the cell membrane and cytoplasm used to catch food and/or movement. An example of a protist with pseudopod is the amoeba. course title 41 Amoeba under microscope!

41. CHARACTERISTICS OF KINGDOM FUNGI They are eukaryotes Many are multicellular, but some are unicellular. All are heterotrophs. Most feed on dead or decaying organisms. They are found almost everywhere on land, but some live in water. Include organisms such as mushrooms, molds, and yeast. course title 42

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45. CHARACTERISTICS OF KINGDOM PLANTAE Multicellular Eukaryotes All are autotrophs (producers), but in a few rare cases, some are also heterotrophs (Venus flytrap) however, they do not get their energy from the flies they trap. Some plants produce flowers, while others do not. Examples of plants are grass, trees, vegetable plants, and weeds. course title 46

46. CHARACTERISTICS OF ANIMAL KINGDOM They are multicellular Eukaryotes Most, but not all, animals can move from one place to another. heterotrophs (consumers). course title 47 We will learn about Animal and Plant kingdom in detail in next lesson.