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Post Darwinian Developments I. Physics A. The Age of the Earth. Post Darwinian Developments I .Physics A. The Age of the Earth 1. 1862 - William Thompson - "Lord Kelvin". Post Darwinian Developments I. Physics A. The Age of the Earth
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Post Darwinian Developments I. Physics A. The Age of the Earth
Post Darwinian Developments I .Physics A. The Age of the Earth 1. 1862 - William Thompson - "Lord Kelvin"
Post Darwinian Developments I. Physics A. The Age of the Earth 1. 1862 - William Thompson - "Lord Kelvin" - molten Earth - 7000oF
Post Darwinian Developments I. Physics A. The Age of the Earth 1. 1862 - William Thompson - "Lord Kelvin" - molten Earth - 7000oF - Based on rate of heat loss and current temp, Earth was 100 million years old
Post Darwinian Developments I. Physics A. The Age of the Earth 1. 1862 - William Thompson - "Lord Kelvin" - molten Earth - 7000oF - Based on rate of heat loss and current temp, Earth was 100 million years old. - Darwin thought it had to be at least 300 million to allow for evolution to occur.
Post Darwinian Developments I. Physics A. The Age of the Earth 1. 1862 - William Thompson - "Lord Kelvin" 2. 1896 - Henri Becquerel
Post Darwinian Developments I. Physics A. The Age of the Earth 1. 1862 - William Thompson - "Lord Kelvin" 2. 1896 - Henri Becquerel - discovers emission of Uranium
Post Darwinian Developments I. Physics A. The Age of the Earth 1. 1862 - William Thompson - "Lord Kelvin" 2. 1896 - Henri Becquerel - discovers emission of Uranium 3. 1903 - Pierre and Marie Curie - discover emission from new element - Radium
Post Darwinian Developments I. Physics A. The Age of the Earth 1. 1862 - William Thompson - "Lord Kelvin" 2. 1896 - Henri Becquerel - discovers emission of Uranium 3. 1903 - Pierre and Marie Curie - discover emission from new element - Radium 4. 1904 - Ernst Rutherford - "The discovery of the radio-active elements, which in their disintegration liberate enormous amounts of energy, thus increases the possible limit of the duration of life on this planet, and allows the time claimed by the geologist and biologist for the process of evolution."
Post Darwinian Developments II. Geology A. The Dynamic Earth
Post Darwinian Developments II. Geology A. The Dynamic Earth - why do coastlines fit?
Post Darwinian Developments II. Geology A. The Dynamic Earth 2. Disjunct Distributions? - southern beech - marsupial fauna
Post Darwinian Developments II. Geology A. The Dynamic Earth Continental Drift - 1915 - Alfred Wegener
- Not accepted until the 1960’s and 1970’s, when sea floor spreading was observed, sonar was used to map the ocean, and paleomagnetism demonstrated where continents had been in the past relative to magnetic north.
Post Darwinian Developments III. Paleontology A. Intermediate Fossils
FISH AMPHIBIANS Ichthyostega - Fins and gill covers (FISH) - Feet (AMPHIBIANS) - After fish, before amphibians (just where evolution predicts it should be) XXX
D. Devonian (417-354 mya) - Placoderms - Sharks - Lobe-finned Fishes 365 mya 385 mya
Archeopteryx • - Fingers, teeth, tail (Reptiles) • Feathers (birds) • - After reptiles, before birds (just where evolution predicts it should be) REPTILES BIRDS XXX
Therapsids REPTILES MAMMALS • - Mammalian skeleton • Intermediate ear • - scales • - After reptiles, before mammals (just where evolution predicts it should be) XXX
Mammals from the Jurassic (185 mya) Therapsids from the Permian (280 mya) to the Triassic (200mya) Pelycosaur Reptiles of the Carboniferous (300 mya)
Australopithecines Australopithecus afarensis
Australopithecines • bipedal (human trait) • chimp-sized cranial volume APES HUMANS - After apes, before humans (just where evolution predicts it should be) XXX
Post-Darwinian Facts I. Physics II. Geology/Paleontology III. Genetics
III. Genetics obviously, the most direct way to test hypotheses of biological relatedness is to compare DNA.
III. Genetics obviously, the most direct way to test hypotheses of biological relatedness is to compare DNA. - DNA comes ONLY from ancestors, and we now how it is replicated and passed to offspring.
III. Genetics obviously, the most direct way to test hypotheses of biological relatedness is to compare DNA. - DNA comes ONLY from ancestors, and we now how it is replicated and passed to offspring. - DNA similarity implies a common source of this DNA – common ancestry. - within a species – paternity tests
III. Genetics obviously, the most direct way to test hypotheses of biological relatedness is to compare DNA. - DNA comes ONLY from ancestors, and we now how it is replicated and passed to offspring. - DNA similarity implies a common source of this DNA – common ancestry. - within a species – paternity tests - Patterns between species? 1. GROSS CHROMOSOMAL SIMILARITIES
2. SEQUENCE ANALYSES - Human and chimp DNA is 98.4% similar in nitrogenous base sequence.
2. SEQUENCE ANALYSES - Human and chimp DNA is 98.4% similar in nitrogenous base sequence. - well, we are similar (mammals, primates, etc.) So, to be similar, don’t we need similar recipes?
B. SEQUENCE ANALYSES - Human and chimp DNA is 98.4% similar in nitrogenous base sequence. - well, we are similar (mammals, primates, etc.) So, to be similar, don’t we need similar recipes? - But, only 10% of the genome is a recipe. Even the 90% that does not code for protein, that is random sequence, still shows 97% similarity. Even non-functional DNA is similar, so functional similarity (ie., ANALOGY) can’t be the answer…the similarity is HOMOLOGOUS.
C. Building Trees and Timing Ancestors Testing Evolutionary Theory (yet again) IF species are descended from common ancestors (like people in a family), and IF we know the rate of genetic change (mutation), THEN we should be able to compare genetic similarity and predict where in the fossil record common ancestors should be.
C. Corroborating Independent Tests of Evolution Now, we date the oldest mammalian fossil, which our evolution hypothesis dictates should be ancestral to the placentals (species 1-16) and the marsupial kangaroo. 16
C. Corroborating Independent Tests of Evolution Now, we date the oldest mammalian fossil, which our evolution hypothesis dictates should be ancestral to the placentals (species 1-16) and the marsupial kangaroo. This dates to about 120 million years. 16
C. Corroborating Independent Tests of Evolution And, through our protein analysis, we already know how many genetic differences (nitrogenous base substitutions) would be required to account for the differences we see in these proteins - 98. 16
C. Corroborating Independent Tests of Evolution So now we can plot genetic change against time, hypothesizing that this link between placentals and marsupials is ancestral to the other placental mammals our analysis. 16
C. Corroborating Independent Tests of Evolution Now we can test a prediction. IF genetic similarity arises from descent from common ancestors, THEN we can use genetic similarity to predict when common ancestors should have lived... 16
C. Corroborating Independent Tests of Evolution This line represents that prediction. Organisms with more similar protein sequences (requiring fewer changes in DNA to explain these protein differences) should have more recent ancestors... 16
C. Corroborating Independent Tests of Evolution And the prediction here becomes even MORE precise. For example, we can predict that two species, requiring 50 substitutions to explain the differences in their proteins... 16
C. Corroborating Independent Tests of Evolution are predicted to have a common ancestor that lived 58-60 million years ago... 16