Exam 1

• Evolution : The process by which the inherited characteristics of a population change over time.
• Evolution

  • To understand patterns
  • can begin to predict future context
• Evolutionary 'theory' is a set of ideas about how evolutionary change occurs.`
• Evolutionary 'theory' : Based on solid evidence

  • continues to be tested
  • Not just one theory
• Theory :

  • a guess or idea
  • isn't always supported reliable evidence or has not enough evidence
• Macroevolution : Change in a line od descent

  • at species level or above
  • usually takes longer time to happen
• Microevolution : change in gene frequency

  • just change in trait, within a population
  • below species level
• Darwin : "Descent with modification"
• II. Historical Context

  A Philosophers : Greeks

  Aristotle : "Chain of being" or "scala naturae”
• II. Historical Context

  B Early Geologists : Studied fossils and strata

  Georges Cuvier - Paleontology and Comparative (1769 - 1832)

  • Did not think species change over time
  • Thought he was digging up species that DIED out over time
• II. Historical Context

  B Early Geologists : Studied fossils and strata

  James Hutton : Scottish geologist. Principle of gradualism

  • Naturally features of landscape form over gradually periods of time through natural processes
• II. Historical Context

  B Early Geologists

  Charles Lyell : geology is the study of the earth's history and the processes that have shaped it

  • 3 volume "principle of geology"
  • Uniformitarianism
• Importance of early geologists ideas

  • gradual changes in earth's landscape
  • occurred by natural processes
  • took extremely long periods of times
• II. Historical Context

  C Early naturalists

  Linnaeus (1707 - 1778) : Swedish physician + botanist systema Naturae

  • binomial nomenclature
  • Hierachical 'nested' classification system
• Domain

  1. Bacteria
  2. Archaea
  3. Eukarya
• KING PHILIP CAME OVER FOR GREAT SEX

  stands for ….

  1. Kingdom
  2. Phylum
  3. Class
  4. order
  5. Family
  6. Genus
  7. Species
• II. Historical Context

  C Early naturalists

  Erasmus Darwin

  Zoonomia : or the laws of organic life

  • survival of the fittest
  • origin and evolution of life over 'millions of ages'
  • relatedness of all forms of life
• II. Historical Context

  C Early naturalists

  Jean Baptiste deLamark (1744-1829): First to propose a mechanism for change

  • Also thought species change over time
  • "Principle of use and disuse" - More they used a feature, more prominant
  • "Inheritance of acquired characteristics" - wrong, only pass of genes in your gametes
• II. Historical Context

  C Early naturalists

  Alfred Wallace (1823-1913) : Naturalist and biogeographer

  • Explored Brazil, Amazon River, then Malay Archipelago
• Mathus (Pub : 1798) : An Essay on principle of populations

  • Big influence on Darwin and Wallace
  • Thought populations were getting too big
  • Food was become more scarce
• Lyell and Hooker published the essays of Wallace and Darwin to Linnean societly jointly in June 1858
• Charles Darwin : published on the Origin of species (1859)
• III Darwins ideas

  Key observations :

  1. Variation of traits in a population (genetic diversity) : Individuals vary
• III Darwins ideas

  Key observations :

  2. Traits are inherited from parents to offspring
• III Darwins ideas

  Key observations :

  3. Species produce more offspring than the environment can support; many die
• III Darwins ideas

  Key observations :

  4. Individuals with beneficial traits survive and reproduce, pass on traits to offspring
• Adaptation : A trait (noun) that favors survival or reproduction
• Natural Selection is a mechanism by which evolution occurs :

  1. Variation —> some traits (adaptation) enhance survival
  2. Because an organism survives and reproduces, it passes on traits to offspring

  Frequency of traits in a pop change as a result of differential survival
• Artificial Selection: The process of selecting for a particular characteristic in a population.
• Sexual Selection : Also a mechanism that results in evolution

  1. Variation : some traits enhance reproduction

  • Some individual produce more offspring than others
  • Reproduction success : Number of offsprings produced

  2. Traits that enhance reproduction success are passed on to offspring

  • frequency of traits in a population change as a result of differential reproduction
• Intrasexual Selection : Within same sex

  ex. Thick mane : harder for males to bite on neck

  Horns : fight

  Body size
• Intersexual selection : Opposite sex

  Compete by influencing members of opposite sex
• Sexual Dimorphism : difference between male and females (how sexual selection differs between the two)
• High Variation : High heterozygosity —> Two different alleles

  Low Variation : high homozygousity —> Two same alleles
• Homologous structures :

  • Structures that different species have in common
  • Evolutonary related in some way
• Homologous structures

  • similar structures / traits in different species due to a common ancestor with that trait
  • Derived from anatomical structure/tissue
• Analogous structures :

  Similar in form and / or function, not due to common ancestry, but to similar pressure

  Covergent Evolution : Similar in form due to similar selection pressure

  • traits derived from same anatomical structures, not similar due to common ancestor
• Homologous DNA sequences : Reveal how species have evolved and allow scientist to map evolutionary history and relatedness of species
• Biogeographic patterns :

  due to plate tectonics + continental shift

  • explain why same / similar species (or evolutionary related species) are sometimes found in different continents
  • Many Island species are similar to closest; but islands also contant unique species
• Evidence supporting evolution

  Contemporary evolution : observable evolutionary change (microevolution) in extant (living) organism