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Unit 1 - Introduction

Unit 1 - Introduction. “bios” – life, living things, “logy” – the study of Biology - the study of life Major branches of biology: Zoology – the study of animals Botany – the study of plants Microbiology – the study of microorganisms

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Unit 1 - Introduction

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  1. Unit 1 - Introduction • “bios” – life, living things, “logy” – the study of • Biology - the study of life • Major branches of biology: • Zoology – the study of animals • Botany – the study of plants • Microbiology – the study of microorganisms • Ecology – the study of the interaction of living organisms with one another and with the non-living part of their environment • Cytology – the study of cells

  2. Questions 1-3, page 6 • How are species related the concept of biodiversity? - Biodiversity is the variety and number of species in a given area • How do the characteristics of living things contribute to an organism’s survival? - The cells that are the basic unit of life carry out the functions needed to support and maintain life, for which they require a continual supply of energy. The ability to respond to the environment helps an organism to avoid injury and death, as well as meet material needs. Reproduction and development enable species survival.

  3. Questions 3-4, page 6 Describe the relationship between cells and organisms. - All organisms are made of one or more cells, which are the functional units of life, carrying out the activities to support life. How does diversity depend on a species’ ability to reproduce? - Without the ability to reproduce, a species would become extinct, which would lead to a decrease in biodiversity.

  4. Question 5, page 6 You respond automatically to many different stimuli, such as loud noises. Why might a quick response to a sound be important? - A quick response could protect against hearing damage or a physical threat.

  5. Questions 1-3, page 11 Describe a biological system. - A system is a group of interrelated, interacting parts that make up a whole. Give an example of how structure is related to function in living things. - Structure determines function; the snout beetle’s feet have prongs and pads to walk on both smooth and rough surfaces. Why is homeostasis essential for living things? - It enables organisms to survive in diverse and changing environments.

  6. Question 4-5, page 11 • What is the relationship between adaptation and natural selection? • Natural selection leads to different adaptations in different environments • How are structure and function related to adaptation? - An adaptation is a genetic change that can affect the structure of some aspect of an organism’s body and how well it functions in a given environment.

  7. Questions 6 & 7, page 11 • How is the process of natural selection involved in evolution? • Natural selection of different adaptations in different environments can lead to new species. • Do you think homeostasis is necessary at the level of the single cell? Explain? - Stable conditions within a cell are necessary for the cell’s survival, whether in a unicellular or multicellular organism. If homeostasis is not maintained within a cell, cell functions can be disrupted. In turn, this can disrupt functions at higher levels of organization.

  8. Questions 1-3, page 17 • What role do hypothesis play in scientific inquiry? • A hypothesis provides a testable explanation of an observation. • What is the difference between an independent variable and a dependent variable? • independent variable is manipulated, a dependent variable shows the effect of that manipulation. • How is the meaning of theory in science different from the everyday use of the term? • A scientific theory is widely accepted explanation that is supported by evidence. In everyday language, a theory is a guess.

  9. Questions 4-5, page 17 4. How are hypotheses and theories related? • Hypotheses and theories are both proposed explanations for a scientific question. Observations and data collected in testing hypotheses contribute to the broader question that is addressed by a theory. A theory, in turn, provides the framework for new hypotheses. 5. Give examples of different ways in which observations are used in scientific inquiry. - Scientific questions are developed from intial observations. Observations are also made to test hypotheses.

  10. Question 6, page 17 Why is the statement “All life is made of cells” an example of a theory? Explain. - When first proposed, the idea that all life is made of cells changed the way scientists thought about what defines an organism. Not only did it encompass all accumulated evidence, but it also provided the framework for new investigations.

  11. Questions 1-3, page 23 • How do light microscopes differ from electron microscopes? - Light microscopes use light to view specimens , including living specimens. Electron microscopes use electrons to view specimens at higher magnifications but cannot examine living specimens. • Why is computer modeling used in biological studies? • To model anything that is not practical or ethical to do in the real world. • How does molecular genetics add to our understanding of genes? • Molecular genetics is the study of inheritance on a molecular level. DNA is the molecule that encodes genetic information. A gene is a segment of DNA.

  12. Questions 4-5 Viruses are smaller than cells. What types of microscopes could be used to study them? Explain. - Light microscopes are not powerful enough to clearly view viruses, so electron microscopes would need to be used. Provide an example of how technology has helped biologists gain a better understanding of life. - Answers could include imaging technologies show more details of cells, computer analysis of genes and genomes, and computer models

  13. Question 6 Genomics can be used to study the genetic relationships among species. Why might genomics be important for evolution research? - By comparing the genomes of different species, scientists can establish how closely related species are finding occurrences of shared DNA sequences and genes.

  14. Questions 1-3, page 27 • Give three examples of ways in which biology can help inform everyday decisions. - Knowledge of biology can inform decisions about diet, using sunscreen, and exercise. • What are some of the potential benefits and risks of biotechnology? - Benefits: treatment and prevention of disease and illness, improving crop growth. - Risks: ethical concerns, privacy, potential negative health and environmental effects • What are some of the unanswered questions in biology? • Life on other planets, cancer cure, viruses, memory

  15. Questions 4-5 • Scientists disagree on whether genetically modified foods are safe to eat. What type of scientific evidence would be needed to show that a genetically modified food is unsafe? - Ex: long-term feeding trials comparing health of animals that do and don’t eat GM foods. The best evidence will be collected over time with humans. Over several years, there will be more data about the health of people who eat GM foods compared with people who do not. • How might your study of biology help inform you about your lifestyle choices? - A knowledge of biology helps you make informed decisions about lifestyle choices that could affect your health and quality of life and health of the environment.

  16. Question 6 • What effects might genetically modified plants and animals have on an ecosystem if they breed with wild plants and animals? - They could decrease biodiversity and affect an ecosystem in unpredictable ways.

  17. Microscope terminology Micrometers – (μm): unit of measurement used for light microscopy (millimeters are too large of a unit). 1 mm = 1000 μm Resolving power: a measure of the smallest distance between two points in the image of an optical system when the two points can be distinguished as separate Parfocal: microscope objectives stay in focus when magnification is changed; i.e., if the microscope is switched from a higher power objective (e.g., 40×) to a lower power objective (e.g., 10×), the object stays in focus

  18. Theories in Biology • Theory: proposed explanation for a wide variety of observations and experimental results. • 3 important theories in biology: • Alvarez Theory • Theory of Natural Selection (Evolution) • Cell Theory (covered in Biology 30 in detail)

  19. Alvarez Theory Developed by Luis and Walter Alvarez Explain the extinction of the dinosaurs 65 million years ago (Cretaceous-Tertiary extinction event). Small asteroid or a large meteorite impacted planet Earth Caused a great deal of smoke and dust that blocked out sunlight for possibly years, caused a “nuclear winter” effect Evidence based on high levels of rare earth element iridium found at the precise fossil layer of dinosaur extinction

  20. Chicxulub Crater Crater found – off the coast of Yucatan Peninsula in Mexico called the Chicxulub Crater – 180 km across, supports Alvarez Theory

  21. Alvarez Theory - continued Theory has gotten stronger support because of seismic and other data Extinction of the dinosaurs allowed mammals to flourish (we are now in the “Age of Mammals”) – Cenozoic Era

  22. What killed the dinosaurs?

  23. Natural Selection (Evolution) Commonly referred to as “evolution” Developed by Charles Darwin – British Naturalist Term used: “survival of the fittest” Darwin sailed the world oceans on the ship HMS “Beagle”, stopped in the Galapagos Islands (in the Pacific off the coast of Peru) Studied many organisms but most famously studies numerous species of finches Darwin observed many different beak shapes based on the food source the finch relied on.

  24. Evolution - continued Darwin concluded that species that were the most suited for a certain environment survived and reproduce Mutations in a species DNA take place over millions of years and most mutations are harmful. However, some mutations give a new species an adaptive advantage (ex: polar bears – white fur allows them to hide from prey species

  25. In 1859, Darwin published his book titled “the Origin of Species” – it is one of the most famous books ever written. Evolution has grown and grown and is now at the foundation of modern biology Evolution is one of the central, unifying theories of biological science

  26. Charles Darwin http://www.youtube.com/watch?v=0Y_6LBcNRN4&feature=player_embedded#at=190

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