Evolution Flashcards
3 processes of evolution
- Variation within a species
- Reproduction
- Selection
Environmental challenges that limit the ability to survive
Weather
Famine
Competition (food, space, mating)
Coevolution
Evolving in conduction with another species. eg. special moth that is the only one who can get snapdragon nectar
Buttesian Mimicry
Harmless species looks like a harmful one. eg. fly that looks like a bee
Mullerian Mimicry
Two harmless species look similar
Peppered moth
Variation to adaptation, lichen was covered in soot and died, so the white moth lost its camouflage and went extinct during Industrial Revolution
Artificial Selection
Humans choose the traits that are passed on. eg. wolf eventually became the chihuahua
Age of the Earth
4.56 billion years old
How was life created?
- Extraterrestrial (panspermia) from comets and meteorites
- On-Earth assembly (hydrothermal vents) chemical reactions that result in the building blocks for life
Primordial Soup
Contains all the nutrients necessary for life
Urey-Miller Experiment
Made primordial soup and came out with formaldehyde, hydrogen cyanide, amino acids, urea
Orion Nebula
Area with the highest potential for life, where the asteroids with the interesting molecules come from
Murchison Meteorite
Collided with Australia, contained all the building blocks for life
Life on other planets
Mars: had flowing rivers (now frozen)
Europa (Jupiters moon): has flowing rivers under ice
Deep-sea thermal vents
Contains sulfur (holds proteins together) and chemotrophs (white smokers)
LUCA
hypothesized universal ancestral cell with all the genes
Oldest known fossil
ancient prokaryotes from Western Australia (filamentous cyanobacteria), 3.5 billion years ago
Cyanobacteria/Stromatolite Fossils
Killed 99% of organisms on the planet because they were obligate anaerobes
Cambrian Explosion and why
When eukaryotic life exploded because of
-Increasing oxygen
-Snowball Earth: Melting of the ice age dripped nutrients into the ocean (2.7 billion year ago)
-Evolution of sexual reproduction and diversification and rapid change
Aristotle
Scale of increasing complexity
Carolus Linnaeus
Binomial nomenclature
Geoges-Louis Leclerc de Buffon
-Pushed back age of the Earth
-Found similarities between apes and humans
Georges Cuvier
Catastrophism
James Hutton
Gradualism
Charles Lyell
Uniformitarianism
Jean-Baptiste Lamarck
-use and disuse
-giraffe theory
-inheritance
Charles Darwin
-natural selection
-finches
-biogeography
Proofs to natural selection
- Fossil records/extinctions
- Biogeography
- Anatomy
- Embryonic development
- Biochemical/DNA analysis
Cytochrome C
a protein in the mitochondria with a long sequence, eg. ours is exactly the same as a chimpanzee. Prove the existence of archaea
Macroevolution
formation of a new species
Microevolution
change of gene pool of a population over time
Hardy-Weinberg Equilibrium
when things stay constant over time, ratio of dominant to recessive alleles stays constant
Disturbing factors of equilibrium
- small population
- natural selection
- mutations
- immigration/emigration
- horizontal gene transfer
Mechanisms of evolution
- genetic drift
- non-random mating
- genetic mutations
- migration
- natural selection
Bottleneck effect
catastrophic event that drastically reduces size of population but it recovers afterwards, small amount of alleles survived
Founder effect
a few individuals from a large population leave and establish a new population, new allele frequencies will not be same as original population (finches)
Types of natural selection
- Stabilizing selection
- Directional selection
- Disruptive selection
Sexual dimorphism
Males and females have different traits for mating purposes (peacocks)
Sexual selection
Traits to attract the opposite sex
Prezygotic isolating mechanisms
- ecological isolation
- temporal isolation
- behavioural isolation
- mechanical isolation
- gametic isolation
Postzygotic isolating mechanisms
- zygotic mortality
- hybrid inviability
- hybrid infertility
Sympatric speciation
evolution of populations within the same geographic area into separate species
Allopatric speciation
evolution of populations into separate species because of geographical isolation
Adaptive radiation
an increase in the morphological and ecological diversity of a species eventually resulting in the formation of a new species. Occurs when a species colonizes a new environment (finches) or by survivors after a massive extinction (dinosaurs)
Uranium dating
goes further back than carbon dating
Molecular evolution
comparing genomic differences, chromosomes patterns, DNA/protein sequences
Australopithecus
-4 MYA
-ape and human like
-small brain, ape-like skull
-trees and land (jungle)
-lots of teeth
-big canines and jaw
Homo
-2 MYA
-human-like
-land dwelling
-skull with capability for speech
-less teeth
-small jaw
-bigger skull
Homo habilis
-1.5-2 MYA
-first tools
-cave dwellers
-jungle
-species stopped evolving
Homo erectus
-1.6 MYA
-advanced tools
-fire
-complex society
-speech capable skull
-continued evolving
Neanderthals
-35-100 TYA
-prominent brow
-short, compact body
Cro Magnons
-35-40 TYA
-our direct ancestor
Convergent evolution
two different species become more similar because of environment.
eg. sidewinder (mojave desert) and horned viper (middle east desert)
Divergent evolution
species that were once similar diverge or become increasingly distinct
Theories of evolution
- Gradualism: small and ongoing changes and processes, transitional species, explained by incomplete fossil records; intermediate forms were not preserved
- Punctuated equilibrium: rapid spurts of change following long periods of little or no change, species evolve rapidly, speciation in small isolated populations and transition species fossils are very rare
Tiktaalik
-transitional species between ocean and land animals
-features similar to tetrapods
