1. Intro to Life Science What is Science? Living Things Where Does Life Come From? Classifying Life

2. 1-1: What is Science ? How do you define science? Science: an organized way of studying things and finding answers to questions Critical thinking: a process that uses certain skills to solve problems

3. Solving Problems Solving problems requires organization Scientific methods: an organized way to solve a problem using a series of procedures ◦ requires critical thinking

4. Scientific Methods State the problem/Ask a question Gather information Form a hypothesis: a prediction that can be tested

5. Scientific Methods Experiment: ◦ Control: standard of comparison in an experiment; cannot change ◦ Variable: something in an experiment that can change An experiment should have only one variable. tests the hypothesis

6. Scientific Methods Analyze data Draw conclusions Report results ◦ allows other scientists to repeat same experiment

7. 7 Steps to Solve a Problem State the Problem Gather Information Form a Hypothesis Perform an Experiment Analyze Data Draw Conclusions Hypothesis Supported Hypothesis not Supported Repeat Many Times Revise Hypothesis

8. Developing Theories The results can be used to develop a scientific theory ◦ an explanation of things or events based on scientific knowledge; the result of many observations and experiments Not just simply a guess or opinion!!!

9. Laws Scientific law: a statement/description about how things work in nature; seems to be true all the time ◦ Ex. Law of Gravity Less likely to change than theories

10. Scientific Units Must make accurate measurements in experiments and investigations Scientists use: ◦ International System of Units (SI)  Standard system of measurements used by scientists  Uses  Gram  Meter  Liter  Second  Celsius Mass Length Volume Time Temperature

12. Lab Safety Must be safe in the lab Follow all safety rules and teacher’s instructions at all times

13. 1-2: Living Things What does it mean to be alive? Any living thing is called an organism May have different behaviors and food needs, but all organisms have similar traits.

14. Characteristics of Life 1. Organization ◦ Living things are organized ◦ Made of cells: the smallest unit of an organism that carries on the functions of life ◦ Each cell has:  an orderly structure  hereditary material (DNA)

15. Characteristics of Life 2. Responsiveness ◦ Living things respond ◦ Stimulus: anything that causes some change in an organism ◦ Response: the way an organism reacts to a stimulus  Ex: Someone hitting you ◦ Homeostasis: maintaining proper conditions inside an organism

16. Characteristics of Life 3. Energy ◦ Living things use energy ◦ Animals get energy from food ◦ Some organisms use the sun to make energy  Ex: plants

17. Characteristics of Life 4. Growth and Development ◦ Living things grow and develop ◦ Growth  can be an increase in number of cells (multi- cellular organisms)  can also be an increase in the size of the cell (unicellular organisms) ◦ Development: changes that take place during the life of an organism

18. 5. Reproduction ◦ Living things reproduce ◦ Creating offspring ◦ Without reproduction, organisms would cease to exist Characteristics of Life

19. What Do Organisms Need? A Place to Live ◦ provides for all the organism’s needs ◦ environment limits where organisms can live Raw Materials ◦ Water, proteins, fats, and sugars ◦ Water is important for all organisms

20. 1-3: Where Does Life Come From? Can mice come from grains? Can earthworms come from the rain? Spontaneous generation: idea that living things come from non-living things Theory finally disproved by Louis Pasteur Biogenesis: living things only come from other living things

21. Life’s Origins How did life on Earth begin? 5 billion years ago, Earth was formed from dust and gas Earth’s atmosphere had no oxygen but it did have ◦ Ammonia ◦ Hydrogen ◦ Methane ◦ Water vapor

22. Life’s Origins Alexander Oparin hypothesized that the gases combined to form more complex compounds found in living things Miller and Urey tested Oparin’s hypothesis ◦ Found that chemicals in living things could be produced ◦ Did not prove that life began this way

23. 1-4: Classifying Life What is classification? ◦ Grouping similar items Organisms can also be classified into groups Aristotle ◦ first classification system more than 2000 years ago ◦ grouped organisms into plants and animals

24. Classifying Life Carolus Linnaeus ◦ Developed a new system based on similar structures of organisms Scientists now study fossils, DNA, and embryos to classify based on phylogeny ◦ evolutionary history of an organism ◦ shows how an organism has changed over time Today, we have 6 kingdoms of classification ◦ Kingdom—Phylum—Class—Order—Family— Genus—Species

25. Six Kingdoms Kingdoms are the first and largest category Smallest classification category is a species ◦ Organisms belonging to the same species can mate and produce fertile offspring

26. A. Bow-Head whale family Balaenidea B. Ganges dolphin family Platanistidae C. Killer Whale family Delphinidae D. Right whale family Balaenidea This is the classification of the bottle-nosed dolphin. Which of the following organisms from the order Cetacea is most closely related to the bottle-nosed dolphin?

27. Scientific Names Common names can be extremely misleading Binomial nomenclature ◦ Two-word system used by Linnaeus to name species; used today ◦ First word identifies the genus: group of similar species ◦ Second word tells something about the species

28. Haliaeetus leucocephalus

29. Using Scientific Names Scientific names are used to: ◦ Avoid mistakes ◦ Show that organisms in the same genus are related ◦ Give descriptive information ◦ Allow information to be organized easily

30. Identifying Organisms 2 types of tools used ◦ Field guides: descriptions or illustrations of organisms  Ex. Bird watching ◦ Dichotomous keys: detailed lists of identifying characteristics that include scientific names  arranged in steps with two descriptive statements at each step

31. Example: 1. Does the organism have a round body? Yes = Go to number 2 No = Go to number 4 2. Does the organism have 2 eyes? Yes = BOT TOT No = Go to number 3 3.Does the organism have 4 antennae? Yes = BOT FOT No = BOT BOT Dichotomous Key