Lecture 2+3: History and evidence of evolution theory Flashcards
Biological diversity (3)
*There is an enormous variation in morphology & ecology
- this diversity is ordered into groups of similar individuals (species)
- different species may be similar or very distinct
Special creation theory (6)
- AKA Linnaean classification
-Earth and life are young
- Species are unchanging.
- Variation = imperfection
-Lineages do not split
-Each Species is created separately
Evolution Theory (4)
-Living species arose from a common ancestor over millions of years.
- Species have been modified (evolved) through time.
- variation ≠ imperfection
- variation = opportunity
cladogenesis
Speciation from common ancestor
anagenesis
Evolutionary change over time
Descent with modificaiton theory (5)
-Species change over time (microevolution)
-Lineages split and diverge over time (speciation)
-New life froms derive from older life forms (Macroevolution)
-All lifeforms are related (common ancestory)
-Earth and life are old
History of descent with modification theory
Used evolution to explain the diversity of species, but had no driving mechanism. That is until darwin went to the glapagos and discovered the fintches, leading him to conclude that natural selection was a thing and the driving force of evolution.
Popular perceptions about evolution (2)
*Fact of evolution widely accepted
- Human evolutionary past often invoked to explain modern human behaviour or physical ailments such as:
– feet, back or knee problems
– obesity
– type 2 diabetes
Paleofantasy perspective (3)
Modern humans evolved in Paleolithic (2.6 mya -12,000 ya).
– Cultural chance has since outpaced evolutionary change, leading to a “gene-culture mismatch.”
– e.g., sugar cravings remanicing from the survival days but now are culturally determental
Evidence for evolution (2 points, 3 subsections)
-Change over time (Micro-evolution, palentology, vestigial organs)
-Common Ancestory ((biogeography, homology, Clinical variation)
Micro-evolution examples (3)
-selective breeding of dogs (artificial selection)
-Farm chickens growing 4x normal size due to artificial selection
-Antibiotic resistant bacteria
Vestigial Organs examples (3)
-Limbs in snake skeletons
-Cavefish “eyes” which initially develop as embryos but degenerate to vestigial organs on head
-Tailbone in humans
Palentology example
-Archaeopteryx as a transition species between dinosaurs and birds
Biogeography examples (2)
-Simmilar species in the same area, ie the glapagos fintches
-Different species filling the same niche in different contenents, like different cactie in different deserts
Clinical Variation
The gradual change in biological traits of a species across a geographic area
Cline (definition + example)
-Gradual change in phenotype across a geographic range (a measurable gradient)
-Fur thickness: Mammals that live in colder climates tend to have thicker fur.
Discontinuity (definition)
-An abrupt shift in phenotype (not a gradual change)
-
Reproductive isolation (definition)
-When populations of organisms fail to hybridize regularly in nature or fail to produce fertile offspring when they do hybridize
Ring Species (definition + example)
- Range which forms a ring. Clinal variation and uninterrupted gene flow around the ring and reproductive isolation where ends meet.
-Ex picture a clock, where at the 12 is one species. Due to a geogrphical block, the species splits around the center of the clock forming a ring. Once population moves to the 11 and one population moves to the 1. At each new number the two populations pass, they become slightly genetically differtent, so much so that by the time they both reach 6, they cannot breed with the other population (reproductive isolation)
Homology examples (2)
-Humans, horses, seals, and bats all having very similar arms that clearly have evoloved from a common ancestor that have since been specialized for grasping, running, swimming and flying
-Genetics, with related species sharing simmilar genes, code etc
who was the other guy who came up with natural selection
Alfred Russell Wallace
