Question | Answer |
Darwin's contribution- 1859 | The Origin of Species |
Participant during the Voyage of the Beagle - 1831 | Darwin |
2. Lyell's Principles of Geology convinced him | Darwin |
observed geographic distribution of animals | Uniformitarian |
unique animals in different locations | Uniformitarian |
slow constant change | faunal succession |
organisms evolving from less complex forms | faunal succession |
survival based on advantage - natural selection | natural selection |
instinct for self or race preservation | natural selection |
need for food | challenge |
don't become food | response |
organs with the same ancestral origin | homology |
but serve different functions, e.g. bat wings | homology |
relatively small, lacking complexity | vestigial organs |
organs with no function, e.g. whales pelvis | vestigial organs |
similar to functioning organs in others | vestigial organs |
developed from the concept of heredity | genetics |
paired strands containing genetic code | chromosomes |
identified by Mendel as particulate inheritance | chromosomes |
made up of DNA | genes |
concentrated within chromosomes | DNA molecule |
won the Nobel Prize | Crick and Watson, Wilkins |
book Double Helix) | Crick and Watson, Wilkins |
chemical changes in DNA lead to | mutation |
genetic makeup (hereditary character) | genotype |
complete set of genes in an organism | genome |
physical characteristics of individuals | phenotype |
total of all genetic components of an interbreeding | gene pool |
origin of two or more individuals from | speciation |
1st Order - 5-8 events in Earth history | extinction |
2nd Order - ~23 events | extinction |
3rd Order - ~33 events | extinction |
rapid expansions of organisms | evolutionary radiation |
new phyla, classes, orders or families | evolutionary radiation |
less competition in new niches | evolutionary radiation causes |
predators have not adjusted to new organisms | evolutionary radiation causes |
often possible because of extinction of other groups | evolutionary radiation causes |
adaptive breakthroughs - key features providing an edge | evolutionary radiation causes |
destruction of groups of organisms | Rates of Extinction |
average mammal species survives for just 1-2 Ma | Rates of Extinction |
average marine species survives for >10 Ma | Rates of Extinction |
high rates of genera extinctions | mass extiction |
Permo-Triassic ~70% marine genera | largest extinction |
phylogeny of life | ‘Tree of Life’ |
new species originate by branching off from others | ‘Tree of Life’ |
species cluster in groups with common traits | ‘Tree of Life’ |
represent higher taxa - more advanced | clusters |
small clusters become a genus | genus |
genera with similar traits become family | family |
Animalae (animal) | Kingdom |
Chordata (vertebrata - backbone) | phylum |
Mammalia (mammal) | class |
Primate | order |
Hominidae (hominid) | family |
Homo | genus |
sapiens | species |
cluster that shares similar traits derived from a common ancestor; | clade |
research emphasizing branching events in phylogeny | cladistics |
early traits | shared biological traits |
derived traits - evolved later | shared biological traits |
mark branching point in evolution | origin of new traits |
illustrated by a cladogram | origin of new traits |
only shows relatively complete groups | cladogram |
useful approach in developing phylogeny | cladogram |
new species arising from older species | phylogeny |
history of one or more genetically related species | lineages |
an individuals changes - life to death | ontogeny |
change in body size - generally increasing | traits |
greater complexity | traits |
longer legs | horse changes |
extension of finger nail | horse changes |
complex teeth | horse changes |
loss of rear legs | change to whales |
increase in size | change to whales |
body streamlined | change to whales |
front legs converted to flippers | change to whales |
species in lineage gradually change | phyletic gradualism |
operates on the entire population | phyletic gradualism |
what Darwin believed was happening due to Natural Selection | phyletic gradualism |
most changes due to rapid, local speciation | punctuated equilibrium |
longer-lived unchanging lineages | punctuated equilibrium |
history of one or more genetically related species | lineages |
debate in paleontology | punctuated equilibrium versus phyletic gradualism (Natural Selection) |
sharp, distinct speciation | Steven Jay Gould |
evolutionary changes are not reversible | Steven Jay Gould |
that contingency has been a critical governing mechanism, | Steven Jay Gould |
along with ‘survival of the fittest’ (phyletic gradualism, | Steven Jay Gould |
also known as Natural Selection), responsible for the life we see on Earth today. | Steven Jay Gould |
A possible future event that can’t be prevented or predicted (“the luck of the draw” concept | Contingency |
species specialization | Adaptive radiation |
diverge from a common ancestor | divergence |
production of similar forms | convergence |
plants - tree form to compete for light | environmental controls |
do it the best way | adapt to efficiency |
adapt to an already successful organism | mimicry |
different species cannot interbreed and produce viable offspring (which can in turn produce offspring) | species concept |
good only for living organisms | species concept |
extremely difficult problem if organism is extinct | species concept |
paleontologists use morphological traits | species concept |
shape, size, proportions | morphological traits |
many problems e.g. lumpers versus the splitters | morphological traits |
right versus left coiling | shape |
abnormally big or small | size, proportions |
most species (>99.9%) never fossilized | Major Problem |
spontaneous mutation of chromosomes | species changes |
constant, slow | gradualism |
fast | punctuated |
predation driving change - yields physical adaptation | competition |
extinct at one locality | migration |
mindless effects; e.g. seeds are dispersed | dispersion |
carried by winds | Atmospheric |
carried by organisms | Atmospheric |
floating or as attachments to floats | oceanic |
floating larvae stages in marine life cycles | oceanic |
slow changes in an isolated gene pool | isolation |
sexual preference within the same gene pool | Sympatric speciation |
most important evolutionary factor | climate |
temperature | primary factors |
moisture | primary factors |
deserts and jungles as barriers | primary factors |
affects marine, terrestrial organisms | sea level changes |
transgression creates barriers | sea level changes |
regression opens pathways | sea level changes |
in part a climatic effect | glaciation |
glaciers destroy things in their path | glaciation |
cools climate and the deep ocean | glaciation |
mountain building events | diastrophism |
land bridges - e.g. Panama uplift | diastrophism |
barriers against migration | diastrophism |
climate modification | diastrophism |
Plate tectonics | Large scale factors contributing to mass extinctions |
changes in climate | Plate tectonics |
isolation of populations | Plate tectonics |
land bridges | Plate tectonics |
Food chain (food webs) disruptions | Large scale factors contributing to mass extinctions |
small population size | Food chain (food webs) disruptions |
low variability (diversity) | Food chain (food webs) disruptions |
narrow adaptation - over specialization | Food chain (food webs) disruptions |
isolation | Food chain (food webs) disruptions |
competition | Food chain (food webs) disruptions |
unrestrained predation | Food chain (food webs) disruptions |
disease | Food chain (food webs) disruptions |
Extreme, rapid changes in physical environment | Large scale factors contributing to mass extinctions |
atmospheric changes | changes in physical environment |
changing climate | changes in physical environment |
volcanic dust | changing climate |
carbon dioxide | changing climate |
meteor impact dust | changing climate |
compositional changes - CO2; O2 | changing climate |
solar radiation changes | Large scale factors contributing to mass extinctions |
sea level changes | Large scale factors contributing to mass extinctions |
lethal increases in chemicals | Large scale factors contributing to mass extinctions |
acidification of oceans, Greenhouse effects | CO2 |
Permo-Triassic extinctions?? | hydrogen sulfide |
nutrient depletion in the oceans | Large scale factors contributing to mass extinctions |
cause reduced phytoplankton production due to lack of upwelling; water mass stability lack of upwelling; water mass stability tectonic stability and reduced runoff | nutrient depletion |
6. ice accumulations (loss) - ocean temperature changes and sea-level changes | Large scale factors contributing to mass extinctions |
low magnetic fields cause strange effects | Magnetic Field Relationships |
extinctions observed near magnetic polarity changes | Magnetic Field Relationships |
during geomagnetic reversals | Cosmic ray effects |
high influx at top of atmosphere - greatest at poles | Magnetic Field Relationships |
mesons, protons, electrons | atomic particles |
effects rapidly reduced by depth of water | Magnetic Field Relationships |
radiation from solar flares | Magnetic Field Relationships |
dumping of Van Allen radiation belts | Magnetic Field Relationships |
atmospheric exposure to the solar wind Solar Wind | Magnetic Field Relationships |
from the Sun - protons and electrons | Plasma stream |
increase in production of radioisotopes at 0 magnetic field | Magnetic Field Relationships |
Killer algae as the ‘kill mechanism’ for 4 of the ‘big 5’ mass extinctions | Controls |
Toxic algal blooms | killer algea |
during planet warming | Controls |
sea level fluctuations | Controls |
excess nutrient supply events; phosphorus and others | Controls |
high CO2 | Controls |
death | Controls |
oxygen depletion by bacteria during decay in oceans | Controls |
anoxia | Controls |
identified with cyanobacteria - stromatolites | anoxia |
toxins produced can kill land organisms | anoxia |
they are volatilized and are absorbed by plants and animals | toxins |
Red Queen Hypothesis (Leigh Van Valen, 1970s) | controls |
evolution and speciation progress at a steady rate | Red Queen Hypothesis |
species do NOT become better adapted | Red Queen Hypothesis |
Tested by Venditti et al., 2010 | Red Queen Hypothesis |
Driving Evolution are steady mutations in organisms | Red Queen Hypothesis |
b. Extinction and Speciation are rare environmental events that cause reproductive isolation | Red Queen Hypothesis |
separation of continents; | reproductive isolation |
genetic change in mating preference; | reproductive isolation |
kingdom, phylum, class, order | modern system |