CH. 1 + 2 (What is Evolution + Written in the Rocks) Flashcards
What was the case of Kitzmiller et al. vs. Dover Area School District?
School board wanted to use creationist texts in the classroom, wanted to encourage students to look for alternative theories to our existence. John Jones III ruled in favour of evolution based curriculum.
William Paley
18th century english philosopher “thought existence of well adapted organisms and their intricate features implied a conscious celestial designer” (finding watch on ground guy)
Evolution
Species undergo gradual change over time (though at different rates)
Gradualism
Takes many years to produce substantial evolutionary change
Speciation
Evolution of different groups that cannot interbreed. If this didn’t happen we would have one highly evolved species.
Does speciation happen often?
No, 99% of organisms go extinct without leaving descendants. However, when speciation does happen it leaves double the chance for future speciation
How can we find common ancestry?
DNA sequencing and fossil remains show us the history of descendent lineages
ex. - Fish, amphibians, mammals are all vertebrates and thus have common ancestor
- reptiles and mammals both have amniotic egg (embryo surrounded by fluid filled membrane called amnion) thus more recent common ancestor
mammals are a subset without amniotes within vertebrates.
phylogeny
evolutionary tree
Carl Linnaeus (1635)
“father of modern taxonomy”, classified animals based on morphological features and recognized that animals similar in features likely had more recent common ancestor
What does natural selection produce?
Fitter, not the fittest. Mutations never really create brand new features , evolution must build a new species based on what already exists.
Scientific Theory
testable, makes verifiable predictions
Retrodictions
facts, data that isn’t predicted by theory but makes sense only in light of said theory
When in history did multicellular life originate and diversify?
Only in the last 15% of life’s history.
Tell me about life on earth (what time periods did they occur)!!!
- Photosynthetic bacteria appeared 3.5 billion years ago in Archean period
- Common consensus is that eukaryotes originated around 1.6 billion - 2.1 billion years ago in Proterozoic Eon (however some studies suggest eukaryotes appeared as far as 2.7 billion years ago)
- multicellular life originated 600 million years ago
600 million years ago - present (time periods)
can be divided into: Paleozoic (543 mil - 251 mil), Mesozoic (251 mil - 65 mil), Cenozoic (65 mil -present)
Paleozoic - Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian
Mesozoic - Triassic, Jurassic, Cretaceous
Cenozoic - tertiary
Significant events in last 600 mil years?
PALEOZOIC
Beginning of cambrian era - cambrian explosion
Silurian Era - jawed fish, terrestrial plants
end of Devonian - tetrapods
end of Carboniferous - reptiles
Triassic period of Mesozoic - Mammals and then birds
Tertiary period of Cenozoic - humans branch from other primates
Principle of Superposition
Proposed by Nicholas Steno. Explains age of strata relative to other layers. Oldest layer at the bottom, most recent on top
- if layer of same type of rock containing same fossils appears in 2 different places the layer is the same age in both places
How can you use radioactivity to test age of rocks?
Radioactive elements in igneous rock can be tested using their known half-lives (Uranium-238 in old rocks, Carbon-14 in newer rocks) to find age. Sedimentary rock cannot be tested in same way but bracketing layers of igneous can give rough age of it.
Why are plankton useful?!
Ideal for showing gradual evolutionary change within a single lineage
- short generations
- they die and fall to sea floor which is an ideal place for fossil formation
- they have lots of hard parts
- there are billions of them so some are bound to turn into fossils
(take columnar core sample from sea floor)
Problems with the fossil record?
- very incomplete
- fossils are preserved but not the environment. What caused evolution?
- soft parts of plants and animals aren’t preserved
Transitional species
patchwork quilt of features from both species
Tiktaalik Roseae
- very important fossil (375 mil years old) that shows how vertebrates came to land
- Found on Ellesmere Island, Nunavut
- Has fins, scales and gills (like fish ancestors) but amphibian features too (flattened head, eyes and notsrils on top of head, and A NECK)
- our ancestors were flat headed, predatory fish
Archeopteryx Lithographica
- most famous transitional species/ form
- 145 mil years old
- Archeopteryx means ancient wing
- mix of reptile (jaw with teeth, long bony tail, claws, separate fingers on wing, neck attached to skull from behind rather than underneath) HOWEVER it had wings with very large feathers and an opposable big toe
Sinornithosaurus Millenii
means “chinese bird lizard”
- had filamentous feathers, head and forelimbs
- found in china
Microraptor Gui
- four winged dino, completely covered in feathers
(long feathers on fore-and hind-limbs) - also found in china
- theropod dinos behaved like birds (behavioural similarities)
How did feathers evolve?
They evolved before birds could fly, and as there is never a step in the process of evolution where the species does not benefit, they must have had another purpose, potentially evolved from same cell that produces scales in reptiles. Early carnivorous dinos evolved longer forelimbs and hands to snatch prey -> grabbing motion = flapping motion
- Trees down: feathers helped reptiles glide tree to tree or tree to ground (food and escape)
- Ground up: feathers helped them leap/glide (could catch prey)
Evidence mammals moved from land to water
- hippos are exactly what you’d expect as a transitional form between land and water (eyes, nose, ears can be closed up tight—all on top of head, mate underwater, babies born and suckle underwater)
- whales, porpoises, dolphins all have vestigial features like rudimentary pelvis and hind legs (evolved from artiodactyls (pigs, camels, etc)
- evolution -> indohyus, pakicetus, ambulocetus, rodhocetus, dorudon, balaena
- evolution happened quickly (wi 10 mil years because predators disappeared from ocean = food source)
Traits Tiktaalik Rosae had that contributed to the evidence that this was a transitional form between fish and tetrapods (amphibian)
- sturdy ribs to help the animal pump oxygen into its lungs (it could intake oxygen through gills and also into lungs)
- unlike lobe-finned fish which had tiny bones it its fins, tiktaalik had fewer sturdier bones similar in position to those found in tetrapods (limbs = part fin, part leg)
