The 7 Characteristics of Life #7 • Order/Organization(Life, Energy, Entropy)R • Regulation R • Growth and Development (via DNA) R • Energy utilization R • Responds to stimuli R • Reproduce (according to a DNA plan) R • E Evolve / Adapt (changes DNA)
The 7 Characteristics of Life #7 E Evolve/Adapt(via changes in DNA) evolution of dance End Chapter 1 Begin Chapter 13
Evolution • Evolution: A change in the genetic make-up of a population. (A change in the gene pool) • Of the 7 characteristics of life, this one is unique in that it is a characteristic of populations. • Individuals are metabolic, homeostatic, respond, grow and develop, reproduce, are cellular, etc. but they DO NOT evolve. Populations evolve, individuals do not !! Evolution is a population phenomenon !! As is perhaps true for much of what you believe about evolution, if you believe that you can evolve, you must unlearn that and learn what is really going on
A Gene PoolEvolution is a change in the genetic make-up of a populationA population has a gene pool; an individual has a genome.
Evolution • The idea of ideas… • A word about words…
Evolution: Biology’s Most Important Idea !Dobzhansky… • Development of ideas in general. • Development of the idea of evolution in particular. • Why? (study this idea in Billeter’s bio class) • Most important idea in biology… • researched, dissected, dissed, poked, kicked applauded, defamed, tested, screamed at, misinterpreted, debated, more than… • Illustrates relation between science and… • Illustrates that science is not divorced from the rest of our society but is rather, science is an integral part of our society. • It is the most powerful paradigm in guiding our understanding of life including human life.
PARADIGMSThere are ideas and there are IDEAS. The biggies are called paradigms. • ATOMIC THEORY • CELL THEORY • PLATE TECTONICS • BIG BANG • E=mc2 • 2nd LAW OF THERMODYNAMICS • ETC.
Evolution • Biology’s most famous book: On the Origin of Species… • Why Darwin? • Why England? • Why 1859? • We’ll come back to this… but be thinking about: • WHY THIS GUY? • IN THIS PLACE? • AT THIS TIME?
EvolutionWhere does this idea come from anyway? • Class Activity 1 (5 minutes): • Make a list of many different living things. (easy) • Group Activity 2 (5 minutes): • Consider your 21 things and all the other living things and formulate 4 of the most basic and fundamental questions you can think of to ask about all of Earth’s living things i.e. What do you think are the most fundamental questions of the science of biology? (hard) e.g. one thing I want to know about life and I think biologists ought to figure out is: how, who, why, what, when, where, what’s up with…
First to make (write down) a distinction between Natural Explanations and Supernatural Explanations So, what did Aristotle think? 384-322 BC
So what did Aristotle ask? 384-322 BC 1. What is the nature of the “soul” or “vital force” of life? What’s responsible for making certain blobs of matter and energy “BE ALIVE”?
So what did Aristotle ask? 384-322 BC 2. Is being alive the same thing for all the life we see around us? Or are there different types of “being alive?” Dolphin, mushroom, sponge, bug…
So what did Aristotle ask? 384-322 BC 3. What’s required to maintain life? i.o.w. What is needed to keep something alive?
So what did Aristotle ask? 384-322 BC 4. Why are there so many kinds of life? (the biodiversity question)
So what did Aristotle ask? 384-322 BC 5. Why are similar organisms similar? How do you account for natural groupings?
So what did Aristotle ask? 384-322 BC 6. Why do like produce like? Why do offspring always resemble their parents?
The Age of Enlightenment • Emerge from Dark Ages 476 A.D. - c.1450 A.D. • Renaissance approx. 1300s -1500s • Age of Enlightenment 16, 1700’s
The Age of Enlightenment • Scientists exhibiting the skepticism and empiricism that characterize modern science. • Questioning established ideas.
Observers of the living world were asking questions too. • The questions of Aristotle are revived. • Historically: • Ages of Exploration and Colonial Expansion. • New and bewildering specimens flood the museums of Europe. • New and bewildering religions and cultures are being “discovered.” • Industrial Revolution. • More on this later…
Big Questions of Biology(1700’s version) • Why is life so diverse? How do you explain the thousands if not millions of species? • What do fossils mean? • Why are certain groups of organisms similar to each other? • Why are others different? • How, if at all, are extant species related to the fossils they resemble? • How, if at all, are similar organisms in different places related?
Evolution? • Many of these questions COULD BE answered quite easily IF organisms could change (evolve). • And most of them COULD NOT be answered well if organisms couldn’t change. • But most 18th C biologists did not believe that organisms evolved. They believed instead…
Evolution? 1. As Aristotle had said about 2000 years earlier, ladder of life… 2. According to the Genesis account in the Judeo/Christian Old Testament… Divine creation a.k.a Special creation.
Challenges to absolute literalism arise from astronomy and geology before biology. Lyell 1797-1875 19C Copernicus 16C Hutton 1726-1797 18C Galileo 1564-1642 17C
So how does a theory of evolution arise out of this 18th century thinking? James Hutton (1726-1797) Theory of Uniformitarianism or Uniformity or Gradualism UniformitarianismvsCatastrophism
3 Implications of Gradualism 1. Earth is very old. • Bishop Ussher (1654) dates the creation of the world at 4004 BC. Sir James Lightfoot improves that calculation to 9 AM Oct 3, 4004 BC. The 6000 year old Earth idea. • Hutton suggests Earth’s age should be measured in at least millions of years. • Modern estimates from radiometric dating and other lines of research age Earth at 4.5 billion.
Three Implications of Gradualism 2. Slow gradual change of the geological world is “normal.”
Three Implications of Gradualism 3. There may be other interpretations of the Judeo/Christian Bible than an absolute literal interpretation. This one really is an implication; Hutton never wrote it. So religious interpretation and empirical interpretation are in conflict. And remain so.
What do these geology ideas have to do with biology??? It’s pretty obvious that organisms “match” their environments.
Had they lived at the same time (they didn’t), Darwin may well have asked Hutton: ‘Hey Jim, if your geologic world is changing gradually and continuously, is it not possible, as a matter fact, is it not likely, that the biological world is changing too?
‘Hey Jim, if your geologic world is changing gradually and continuously, is it not possible, as a matter fact, likely, that the biological world is changing too? Well, perhaps. But ya gotta have a MECHANISM !!! If ya wanna say somethin’s happenin’ ya gotta explain HOW !!
Jean Baptiste Pierre Antoine de Monet Chevalier de Lamarck(1744-1829)takes a shot at answering “How?” Evolution Through the Inheritance of Acquired Characteristics Acquired Characteristics = non-Genetic Characteristics
Jean Baptiste Pierre Antoine de Monet Chevalier de Lamarck(1744-1829) Evolution Through the Inheritance of Acquired Characteristics
Jean Baptiste Pierre Antoine de Monet Chevalier de Lamarck(1744-1829) Evolution Through the Inheritance of Acquired Characteristics The real poop on giraffes: Click HERE for a great video on giraffes. Nope !
Lamarck’s idea does not survive So…we turn to Chuck Darwin1809-1882
Charles Darwin 1809-1882 Voyage of HMS Beagle 1831-1836 “On the Origin of Species” 1859 JB
1837 Darwin begins analyzing his specimens and writing his notebooks on the origin of species. Fig. 13-02 1809 Lamarck publishes his theory of evolution. 1844 Darwin writes his essay on the origin of species. 1830 Lyell publishes Principles of Geology. 1865 Mendel publishes papers on genetics. 1800 1870 1809 Charles Darwin is born. 1859 Darwin publishes The Origin of Species. 1858 Wallace sends an account of his theory to Darwin. 1831–36 Darwin travels around the world on the HMS Beagle. Green sea turtle in the Galápagos Islands
Evolution • Biology’s most famous book: On the Origin of Species… • So… we ask again? • Why Darwin? • Why England? • Why 1859? So, let’s address these questions… What ‘s up with THIS GUY in THIS PLACE at THIS TIME ???
Science is always affected by the larger society in which it operates. (Heck, almost everything is affected by the larger society in which it operates !!) Age of Exploration (mid 1400’s - mid 1500’s) Age of Colonial Expansion (early 1500’s – late 1700’s +) the voyage of the Beagle was part of the Colonial Era Industrial Revolution (1730’s – early 1900’s) How do these large scale social/historical events affect Darwin and the development of evolutionary theory?
-- the growth of natural history museums -- lavishly illustrated coffee-table books
The Voyage of the H.M.S. Beagle1831-1836 Fig. 17-6c, p.265
Convergent EvolutionRhea, SA; Emu, Aust; Ostrich, Africa Fig. 17-3a, p.262