4 Early Ideas about Earth’s Organisms Aristotle believed species were fixed creations arranged by their complexity
5 Early Ideas about Earth’s Organisms Carolus Linnaeus1st to group similar organisms and assign them Latin namesTwo word name (Genus species)Known as Binomial nomenclature
6 Early Ideas about Earth’s Organisms Georges CuvierSome species’ fossil records disappeared in more recent layersStated that species disappear due to a catastrophic event of the earth’s crust
7 Early Ideas about Earth’s Organisms James Hutton & Charles LyellStated that various geological forces constantly changed the planetChanges in Earth’s crust were due to slow continuous processesIdea Known as Gradualism or Uniformitarianism
8 Early Ideas about Earth’s Organisms Hutton & Lyell, cont.Geological processes moved at uniform rates; building & wearing down Earth’s crustProposed that the Earth was millions of years instead of a few thousand years old
9 Early Ideas about Earth’s Organisms Reverend Thomas MalthusStudied macroeconomicsStated that populations could not grow indefinitelyThis growth would be stopped by:DiseaseFamineWar
10 Lamarck’s Theory of Evolution Jean-Baptiste LamarckOne of first scientists to understand that organisms change over timePut forth an idea called Inheritance of Acquired Characteristics through Law of Use and Disuse
11 Lamarck’s Theory of Evolution Proposed that by selective use or disuse of organs, organisms acquired or lost certain traits during their lifetimeExamples:blacksmiths & their sons (muscular arms)giraffe’s necks longer (from stretching)These traits could then be passed on to their offspringOver time this would lead to new species
13 Lamarck’s Mistakes Inheritance Of Acquired Traits Traits Acquired During Ones Lifetime Would Be Passed To OffspringIf true, clipped ears would pass to offspring!
14 Lamarck’s MistakesLamarck did NOT know how traits were inherited (traits are passed through genes)Genes are NOT changed by activities in the life of an organismChange occurs through mutations of genesThese mutations occur before the organism is born
16 Charles DarwinBorn Feb. 12, 1809A naturalistCollector/identifier of plant and animal specimensFormed his ideas about evolution sailing on the HMS Beagle for the Galapagos Island in 1831
17 The Galapagos Islands Small group of islands 1000 km west of Ecuador Very different climates and geography on each islandAnimals on each of the islands similar but unique
18 The Galapagos Islands Islands all formed by action of volcanoes Island species varied from mainland species & from island-to-island speciesEach island had long or short neck tortoises
19 The Galapagos IslandsFinches on the islands resembled a mainland finchDifferent types of finches appeared on the islands where the available food was different (seeds, nuts, berries, insects…)Finches had beaks adapted to their type of food gathering
26 Darwin’s Observations Unlimited resources will allow organisms increase exponentially, generation to generationIn nature, populations tend to remain stable in sizeEnvironmental resources are what limits population size
27 Darwin’s Observations Individuals of a population vary in their characteristics with no two individuals being exactly alike.Much of this variation between individuals is inheritable.
28 Darwin’s ConclusionsProduction of more individuals than can be supported by the environment leads to a struggle for existenceOnly a fraction of offspring survive each generationHe called this “Survival of the Fittest”
29 Darwin’s ConclusionsIndividuals who inherit characteristics most fit for their environment are likely to leave more offspring than less fit individualsHe called this “Natural Selection”
31 Ideas that Shaped Darwin’s Thinking Hutton & LyellExpanded Earth’s age from 6000 to billions of yearsExplained geological processes that shaped the earthHelped Darwin understand the presence of sea shells in the Andes mountains at 12,000+ feet
32 Ideas that Shaped Darwin’s Thinking Malthus’ InfluenceBabies are born faster than people dieTotal population size limited by resources such as the food supplyHigh birth rates & limited resources would force life & death competitionEach Species Struggles For:FoodLiving SpaceMates
33 Darwin’s Theory of Evolution Organisms Change Over Time
34 Evolution: DefinedEvolution is the slow , gradual change in the alleles of a population over time
35 Darwin’s Theory of Evolution The unequal ability of individuals to survive and reproduce leads to a gradual change in a population, with favorable characteristics accumulating over generations (Natural Selection)This creates new species
36 Darwin’s Theory of Evolution Descent with Modification:Organisms descended from common ancestorsOrganisms change with time, diverging from a common form
37 Darwin’s Theory of Evolution Natural Selection:Driving force for evolutionDuring the struggle for resources, strongest survive & reproduceIdea that at least some of the beneficial differences between individuals are inheritable.
38 Publication of: “On The Origin of Species” Upon his return To England, Darwin spent 25 years developing his observations into the Theory of EvolutionHe hesitated to publish because:1. He knew that his theory would be extremely controversial and would be attacked2. His theory challenged established religious & scientific beliefs; particularly about the Creation of Man
39 “O’ no you didn’t! This was my Idea!” - Darwin Alfred Russel WallaceFellow naturalistSent an essay of his work to Darwin to reviewHad independently come to the conclusion that species changed over time because of their struggle for existenceWhen Darwin read Wallace’s essay, he knew he had to publish his findings
40 Publication of: “On The Origin of Species” Darwin presented Wallace’s essay & some of his work at a conference in July of 1858Then he started work on his book “Origin of Species” which was published in 1859Spent the rest of his life refining his ideas about evolutionDarwin died in 1882, the father of 10 children; 7 survived to adulthood
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