4. Respond to Surroundings -All organisms react to changes in their environment. *Stimulus—something that causes an organism to react. (a sight, sound, smell, touch or taste). Here the stimulus is the sight of the fly. *Response—how an organism reacts or behaves to the change. The response is catching the fly.

5. Grow and Develop -All living things grow and develop. *Growth—living things increase in size. *Development—the process of change that occurs as an organism grows, producing a more complex organism.

6. Reproduce -All living things produce offspring similar to themselves.

Where does Life Come From • -Four hundred years ago, people believed that living things could come from nonliving material. • This idea was called Spontaneous Generation. • -Two scientists, Francesco Redi and Louis Pasteur worked to prove that this theory was incorrect.

- What Is Life? Redi’s and Pasteur’s Experiments • Click the Active Art button to open a browser windowand access Active Art about Redi’s and Pasteur’sexperiments.

- What Is Life? Life Comes From Life • In 1668, Francesco Redi designed one of the first controlled experiments. In his experiment, Redi showed that flies do not spontaneously arise from decaying meat.

- What Is Life? Life Comes From Life • Nearly 200 years later, in 1864, Louis Pasteur’s carefully controlled experiment demonstrated that bacteria arise only from existing bacteria.

Biogenesis replaces Spontaneous Generation • -In 1870, Thomas Huxley developed the theory of Biogenesis to replace Spontaneous Generation. • *It states: living things arise from living things through • reproduction. Bio = life Genesis = beginning

The Needs of Living Things • -All living things have the same basic needs: Water Food Living Space Makes-up 70% of most living things Autotrophs—make their own food Organisms need a place to live Stable Internal Conditions (homeostasis) Organisms must be able to keep conditions inside their bodies constant Heterotrophs—can not make food

- What Is Life? The Characteristics of Living Things • Click the Video button to watch a movie about the characteristics of living things.

- What Is Life? Using Prior Knowledge • Look at the section headings and visuals to see what this section is about. Then write what you already know about living things in a graphic organizer like the one below. As you read, write what you learn. What You Know Living things grow. Living things are made of cells. What You Learned Unicellular organisms are composed of only one cell. The cells of living things are composed of chemicals. The cells of organisms use energy to do things they must do.

End of Section:What Is Life?

Classifying Organisms • -Classification is the process of grouping things based on their similarities. • -Taxonomy is the science of classifying living things.

- Classifying Organisms Aristotle and Classification • Many hundreds of years before Linnaeus, a Greek scholar named Aristotle developed a classification system for animals. Aristotle first divided animals into those he considered to have blood and those he did not. This graph shows Aristotle’s classification system for “animals with blood.”

3 Reading Graphs: Into how many groups were these animals classified? - Classifying Organisms Aristotle and Classification

Animals that fly Interpreting Data: Which group made up the largest percentage of animals? - Classifying Organisms Aristotle and Classification

78% Calculating: What percentage of these animals either fly or swim? - Classifying Organisms Aristotle and Classification

Cow- animals that walk, run, or crawl; whale- animals that swim. Inferring: In Aristotle’s classification, where would a cow be classified? A whale? - Classifying Organisms Aristotle and Classification

Possible answer: This system includes only three categories, so it may not be very useful today. It also does not match that of modern scientists, who use characteristics other than movement to classify animals. For example, frogs and lions belong to very different groups. Predicting: Would Aristotle’s classification system be used today? Explain. - Classifying Organisms Aristotle and Classification

The Naming System of Linnaeus -In the 1750s Swedish scientist, Carolus Linnaeus developed the system of naming living things called binomial nomenclature. *Each organism is given a unique, two-part name made up of its genus and its species. *Example: Felis domesticus (house cat)

Levels of Classification • -Today, organisms are grouped together based on shared characteristics into various levels. The largest level is called the Domain. • -A domain is then divided into: kingdom, phylum, class, order, family, genus and species levels. • *Use this to help you remember the correct order : • “Didn’t King Phill Come Over From Great Spain?” • “Don’t Kids Prefer Candy Over Fresh Green Salad?”

- Classifying Organisms Levels of Classification • As you move down the levels of classification, the number of organisms decreases. The organisms at lower levels share more characteristics with each other.

- Classifying Organisms Taxonomic Keys • Taxonomic keys are useful tools for determining the identity of organisms.

What is it????

- Classifying Organisms Evolution and Classification • Species with similar evolutionary histories are classified more closely together. These Galapagos finches may have arisen from a single species and changed gradually over time to become three separate species. Notice the differences in their appearance, especially their beaks. eats eats eats

Question Answer - Classifying Organisms Asking Questions • Before you read, preview the red headings. In a graphic organizer like the one below, ask a what, why, or how question for each heading. As you read, write the answers to your questions. Why do scientists classify? Scientists classify because they want to organize living things into groups so they are easier to study. What system did Linnaeus use to name organisms? He used a system called binomial nomenclature. What are the levels of classification? Domain, kingdom, phylum, class, order, family, genus, species

- Classifying Organisms More on Classifying Living Things • Click the PHSchool.com button for an activity about classifying living things.

End of Section:Classifying Organisms

- Domains and Kingdoms Three Domains of Life • In the three-domain system of classifications, all known organisms belong to one of three domains–Bacteria, Archaea, or Eukarya.

Domains and Kingdoms • -Organisms are placed into domains and kingdoms based on their cell type, the number of cells in their bodies, and their ability to make food. • *Note: Cell type is either: eukaryotic—with a nucleus • or • prokaryotic—without a nucleus Bacteria—prokaryotic, single cells. Some can make food and some can not. Archaea—prokaryotic, single cells. Some can make food and some can not. The difference is they do NOT need oxygen to live. Eukarya—eukaryotic cells. Divided into four kingdoms: Protists, Fungi, Plants and Animals.

- Domains and Kingdoms Comparing and Contrasting • As you read, compare and contrast the characteristics of organisms in domains Bacteria, Archaea, and Eukarya by completing a table like the one below. Characteristics of Organisms Domain or Kingdom Cell Type and Number Able to Make Food? Bacteria Prokaryotes; unicellular Some are able to make food Archaea Prokaryotes; unicellular Some are able to make food Eukarya: Protists Eukaryotes; unicellular or multicellular Some are able to make food • Fungi Eukaryotes; unicellular or multicellular No • Plants Eukaryotes; multicellular Yes • Animals Eukaryotes; multicellular No

- Domains and Kingdoms Links on Kingdoms • Click the SciLinks button for links on kingdoms.

End of Section:Domains and Kingdoms

The Origin of Life • -If living things come only from other living things then…. • -where did the first living thing come from? • -Scientists have a theory…

- The Origin of Life The Atmosphere of Early Earth • On ancient Earth, water vapor, carbon dioxide, and methane were probably the most abundant gases in the atmosphere. There were frequent volcanic eruptions, earthquakes, and violent storms. There was no oxygen in the atmosphere. Most of the living things present today could not have survived these conditions.

Life on Early Earth • -A Russian scientist, Alexander Oparin, suggested that over millions of years, chemical elements and compounds joined together under these very different conditions to form proteins—the building blocks of cells. • -Eventually, these could copy themselves and use other chemicals for food. • -They evolved into the first living cells about 3.5 - 4.0 billiion years ago.

Evidence for this Theory • -Fossils resembling today’s archaebacteria have been discovered dating back to 3.5 billion years ago. • -American scientists, Stanley Miller and Harold Urey’s electric spark experiment in 1953, showed that substances present in living things (like proteins) could come from nonliving material. • -This experiment did not PROVE that this happened—only that it is a possibility.

- The Origin of Life Identifying Supporting Evidence • As you read, identify the evidence that supports scientists’ hypothesis of how life arose on Earth. Write the evidence in a graphic organizer like the one below. Evidence Fossil evidence of achaea-like organisms Hypothesis Origin of life Fossils dated to be between 3.4 and 3.5 billion years old.

- The Origin of Life Links on the Origin of Life • Click the SciLinks button for links on the origin of life.

- The Origin of Life Modeling Conditions on Early Earth • Click the Video button to watch a movie about modeling conditions on early Earth.

End of Section:The Origin of Life

Graphic Organizer Living Things need Homeostasis Food Living space Water made by to provide Autotrophs Shelter Food & water eaten by Heterotrophs

End of Section:Graphic Organizer

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