Exam 1 Flashcards
what is the powerful evidence for the process of evolution?
intermediate fossils
-EX: turtle ribs not fully enclosed yet and was a mixture of turtle and marine life
what two countries were ranked lowest in believing evolution?
US and Turkey
What did Charles Darwin do?
-published first modern understanding of evolution
-idea was published before him, but Darwin found more evidence
when did Darwin publish the first modern understanding of evolution?
1859
what is the copernican principle?
-Earth is not the center of our universe
-Special Creation and Descent with Modification
What is special creation?
-species don’t change
-lineages don’t split
-earth is young
-NO EVIDENCE to prove this
what is descent with modification?
-species change over time
-lineages split and diverge
-new forms come from older forms
what is microevolution?
-changes in species
-species are not ‘fixed’
microevolution in mice on wheels
-ran mice on wheels
-bred only the fast mice together
-after 24 generations, the avg. speed of mice increased compared to control group
microevolution in artificial selection in dogs
-continued to breed only the ‘cute’ dogs
-they can all cross breed due to them being the same species
-have different phenotypes
microevolution in mustard seeds
-mustard seeds grown in the wild
-lots of rain = long growing szn
-drought = short growing szn
-produced a hybrid of the plants
what are vestigial traits?
useless body parts from former allied species
-evidence for microevolution and descent w/ modification
vestigial traits in snakes and humans
snakes: has hindlimbs but can’t walk
humans: has a coccyx but no tail, has pili muscles but no warning signal to others
vestigial traits in stickleback fish
marine fish: fully armored
freshwater fish: no armor
-when the two waters combined, the fish adapted to the environment by being better or less protected
-proves both types of fish have both alleles for the phenotype
what is the Biological Species Concept? and who created it?
-if individuals from a population interbreed and do not produce offspring they are different species
-Mayr and Dobzhansky
what are limitations to the biological species concept?
-fossil species
-asexual organisms
-allopatric speciation
-organisms that freely hybridize
what is reproductive isolation?
-inability of a species to breed successfully with related species
-due to geographical, behavioral, physiological, or genetic barriers or differences
what is viral speciation?
one species evolving into two
what is incipient speciation?
-alleles start to separate
-rarely interbreed
-all their male offspring are sterile
what are the four stages of evolution?
- variation among individuals (24 different colored fish)
- divisions into distinguishable individuals (8 blue, 8 purple, 8 red)
- distinct populations with little interbreeding (10 blue, 4 purple, 10 red)
- populations with irreversible reproduction isolation (12 blue, 12 red)
stages of evolution in stickleback fish
-gill rackers are related to diet
-gill rackers are big in some fish and small in others
-eventually the forms were no longer allowed to interbreed anymore due to such drastic genetic changes
-created two separate species (no longer could breed)
stages of evolution in ring species
-populations migrated around the Tibetan Plateau
-they adapted to local conditions
-when they came into contact, they no longer could interbreed
-created two separate species
what is macroevolution?
major changes that creates a new form from an earlier/older form
-emphasis on major lineages (looks at fossil record)
macroevolution in Irish elk
-an extinct animal
-scientists didn’t believe in extinction
-thought it was an intermediate fossil
Law of Succession
-extinct species resemble species currently living in the same location
-species die out, but a new species replaces it
-fossils and living organisms in the same location geographically
What are transitional forms?
the inbetween organisms of a species being evolved
transitional form of the blenny fish
fish that could jump on land and swim in water
transitional form of a dinosaur and a bird
had feathers but couldn’t fly
-birds adapted feathers before they adapted flight
what is homology?
the study of likeness
-adapted for the environment and survival
-EX: human arm, dolphin fin, dog leg, bat wing
what is nonhomologous?
two species that appear to have homology but don’t
-shark and orca have fins but aren’t related
what percentage of all species that have ever lived are extinct now?
99%
how is common ancestry tested?
through nested sets
what are nested sets?
take what species share and use common traits to create a tree
-works with fossils
what is molecular homology?
homology with genes when comparing species
what are pseudogenes?
-nonfunctional genes
-from accidental reverse transcription, are inserted back into the genome
-lack introns and promoters
what is Universal Homology?
the same three codons specify the same amino acid in a protein
what is radioactive dating?
-proved that the earth is billions of years old
-determined half life of an element to figure out its lifespan
what is speciation?
-lineages split and diverge into new species
what is natural selection?
-explanation to adaptations and survival in species
-organisms better adapted to their environments live and reproduce
Natural selection in agriculture
-better looking tomato’s get picked over the smaller ugly tomato’s
-thru artificial selection we made them bigger and better
natural selection in vegetables
-people selected traits of plants that they liked more than the others and bred them
-over time different species were created
Process of Natural Selection
- variation in a population
- differences are passed to offspring
- those better at surviving reproduce
- continue to reproduce and creation of variant trait
EX: brown mice die out while white mice survive better and live
Darwinian Fitness
-individual’s ability to survive and reproduce
-those who are most physically fit are not always the ones that reproduce and survive
-adaptations aid this process and increase organisms fitness
Darwinian Fitness in Gulls (bird)
-tested survival in birds with low, medium, and high muscle mass
-medium lived
-low and high muscle died out
can bumblebees drive evolution of flower color?
yes
-white plants were picked over yellow plants
-more white plants were found in offspring compared to yellow plants
-small changes over time can accumulate
What did Grant do?
-determined genes play a role in evolution
-did a capture-mark-recapture study
-beak and finch size correlates to food type
-the desired trait depending on food available was heritable and passed to offspring
what are exaptations?
adaptive traits used in a new way
-they previously had a different function
EX: carnivorous plants and sticky liquid defense
Is evolution perfect in stating that only “survival of the fittest” survive?
No
-is mosquitofish, the females prefer male fish with big anal fins
-males having a bigger anal fin are more susceptible to predators
-shows that conflicting selection pressures proves evolution isn’t goal-oriented towards perfection but leads to adaptation
what is pangenesis?
gemmules were tiny particles of info
-each part of the body continually emitted its own type of small organic particles
what is blending inheritance?
-favorable variants merge into existing traits and are lost
-INCORRECT
-phenotypes blend, but not genotypes
what is modern synthesis?
it combined genetic inheritance with evolution by natural selection
what is the pathway of modern synthesis?
- individuals vary due to mutations, the alleles are shuffled to make new combinations
- alleles are passed to offspring
- some are more successful at surviving and reproducing
- ones who are successful have alleles that best adapt them to the environment
what is the scopes trial of 1925?
-a law case with biology teacher John Scopes who taught evolution in his class
-opened up a debate on whether or not we should be allowed to teach evolution
how did half an eye prove evolution and genes?
-ciliary photoreceptors (light sensing organ) that was see as a complex organ is the same in 5 chordates
-proved that they have a common ancestor
What was the Euk. cell flagella used to disprove?
-tried to disprove Darwin by saying that there are complex organs that don’t have slight modifications throughout history
-failed
why were crystalline proteins in animal lenses important in proving evolution?
-all derived from proteins with other functions in other tissues
-same in several species
-supported evolution
