BIO 105 1st Edition Lecture 10Outline of Previous LectureI. How did life on Earth first evolve?II. How did the Earth get Oxygen?III. What kinds of prokaryotes do we have on Earth now?IV. What are the eukaryotic microbes and what do they do?Outline of Current LectureI. How did plants evolve to live on land?II. What types of plants are there, and what are their relationships and differences?III. How are plants adapted to their environments?IV. How do plants get the resources they need?Current Lecture Biology 105 Evolution and Selection"Nothing in biology makes sense except in the light of evolution" -- T. Dobzhansky, 1973Essential Questions1. How do we know that something is alive? 2. How did Lamarck, Darwin, and Wallace contribute to our understanding of evolution?3. How does evolution by natural selection occur?4. What is the relationship between genetics and evolution? 5. How do artificial and sexual selection, mimicry and coevolution relate to the central concept of natural selection? Interactive Class NotesHow do we know that something is alive? I. Characteristics of lifeA. There is a fundamental similarity among all living things on Earth and their challenges. B. All living things are composed of cells, consisting of internal cytoplasm surrounded by a membrane. These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is bestused as a supplement to your own notes, not as a substitute.C. Life has a complex, hierarchical organization. Cells are constructed from thousands of kinds of molecules, found in highly organized arrangements. In multicellular organisms, the cells form tissues, which form organs and organ systems. D. All organisms need energy provided by metabolic reactions. Examples of metabolic reactions include respiration and photosynthesis. E. Cells require homeostasis, the ability to maintain constant environmental conditions.F. Living things undergo growth and development. Cells grow to make larger organisms and/or more organisms. Organisms develop in response to their genetic programs and environmental influences. G. All organisms reproduce and pass their genes to the next generation. Many species can reproduce both sexually and asexually.H. All living organisms respond to stimuli. Animals run from danger, capture food, and build nests. Plants and microorganisms also respond to their environments, often through the production of chemicals or changing their growth pattern. I. All organisms adapt to their environments through the process of evolution by natural selection. a. Evolution allows us to organize our understanding of living organisms and their relationships. It provides context for new facts and ideas about plants and animals. How did Lamarck, Darwin, and Wallace contribute to our understanding of evolution?Definition of evolution: A gradual process in which something changes into a different and usually more complex or better form. (Biology) The theory that... species change with time so that descendants differ morphologically and physiologically from their ancestors (Am. Heritage Dictionary)I. History of evolution A. Anaximander and Lucretius believed that living things were related to one another and had changed over time. 1. Aristotle wrote of a ‘ladder of nature’ with perfection increasing from inanimate objects up toGreek men. 2. Evolutionary thought was later overshadowed by medieval biblical interpretations of nature. B. Until the 18th century, most Western scientists believed that life was created by God, includingthe ideas that 1. Life is organized into a fixed number of species. 2. Species arose during the Creation and did not change thereafter. 3. Creationism is not a scientific hypothesis, but it provides testable predictions: a. All species and the Earth itself should be the same age b. The species composition of the Earth has not changed over time. C. By the late 1700’s these predictions were found to be incorrect. The Earth is extremely ancient, and organisms were discovered that had lived in the past but were now extinct. 1. The theory of gradualism stated that geological processes in the past operated like they do today. a. Geologists showed that if processes like erosion, mountain building, cave formation, etc. occurred in the past at today’s rate, the Earth must be billions of years old. 22. Biologists realized that fossils are actual remnants of ancient organisms, and that in general, the farther down a fossil was found, the older it was, so the order of fossils in the rock reflected when organisms had lived. 3. Most scientists in the 1800’s accepted the idea of changes in the diversity of life on earth, or evolution, but they could not explain it. 4. Jean Baptiste Lamarck offered an early idea: inheritance of acquired characteristics. He proposed that (1) organisms change as they get adaptations that they need through interaction with the environment, and (2) that their offspring inherit these changes. a. Lamarck hypothesized that giraffes stretched their necks to reach higher leaves, and this stretching slowly lengthened their necks. Their offspring inherited these lengthened necks, and stretched them more, so over time giraffes' necks become longer. b. A weakness in Lamarck's hypothesis it that he did not offer a mechanism to explain how these inheritance changes may have occurred and been inherited. But, genetics and inheritance were a mystery to everyone at that time. i. Experiments done to test Lamarck’s hypothesis invariably did NOT support it. ii. Even after many generations of cutting the tails off mice, the baby mice were always born with tails. The environmental alteration of losing their tails was never inherited by the offspring. iii. Human example: Arnold Schwarzenegger's kids have to work out to get muscles; they aren't born with them!KEY POINT: Lamarck proposed an unsuccessful hypothesis for evolution, the inheritance of acquired characteristics. D. Another evolutionary hypothesis was developed by Charles Darwin and Alfred Russell Wallace.1. Neither Lamarck nor Darwin and Wallace were the first to propose evolution. The idea had been around a long time; Darwin's grandfather Erasmus Darwin studied it. 2. Darwin and Wallace were the first to suggest a believable mechanism, supported by evidence, by which evolution