introduction to evolution, biodiversity and deep time Flashcards
what are the 6 propositions of Neo-darwinian theory
1) Reproduction
2) Excess
3) Variation
4) Environmental selection (natural selection)- always variable, can change
5) Divergence- different environment acting on characters which leads to speciation
6) Ancestry
-survival of the fittest
-darwin and Wallace worked out evolution but couldn’t get their heads around heredity due to not enough info yet
what is biodiversity
-Biodiversity is the variety of life, in all its manifestations. It encompasses all forms, levels and combinations of natural variation
-evolution causes biodiversity to always change due to extinction and speciation
whats taxonomy
-the science of classification of organisms
whats phylogeny
-the study of evolutionary relationships
what does evolution occur via
-neo-Darwinian evolution (descent with modification through natural selection). Thus taxonomy and phylogeny are intimately linked as we attempt to classify organisms (taxonomy) and
what does phylogeny reflect
-our taxonomy
whats deep time
-As the reality of deep time gradually dawned Victorian scientists began reluctantly to peer over the abyss into the unfathomable depths of deep time
-ways to work our time of how long things have been around
-millions of years old
Phanerozoic period
period:
-quaternary
-neogene
-paleogene (all cenozoic)
-cretaceous
-jurassic
-triassic (all mesozoic)
-permian
-carboniferous
-devonian
-silurian
-ordovician
-cambrian (all paleozioc)
-cenozoic= 1.4%
-mesozoic= 3.9%
-paleozoic = 7.1%
-hadean = 14%
-archaen = 31.5%
-proterozoic = 41.9%
is the fossil record complete or incomplete
-incomplete
why is the fossil record incomplete
1) Very few of the organisms that ever live will end up being fossilized (and ultimately collected and studied);
2) Entire species or higher taxa may not be preserved in the fossil record. This is particularly true for those:
-with low preservation potential- bones, teeth, shells all highly preserved
-with small population
-that inhabit a small geographical area
-that lived for only a short period of time
why is the fossil record biased
1) Certain environments are more likely to be preserved than others, i.e. those with net deposition rather than net erosion. Thus:-
-Marine organisms are more likely to be preserved than terrestrial organisms
-Terrestrial lowland deposits (e.g. nearshore and floodplain) are more likely to be preserved than upland deposits
2) fossils of aquatic organisms, or organisms that find their way into aquatic environments, are much more likely to be preserved.
3) Organisms with recalcitrant, and therefore more readily preserved, tissues are more likely to be preserved (e.g. bone, tooth, wood, shell versus soft bodied organisms)
how has the environment changed throughout time
-The environment of planet Earth is spatially variable today.
-The environment of planet Earth is temporally variable
(diurnal, seasonal)
-But the environment has also changed over longer periods of time (e.g. Milankovitch cycles ) or even over vast periods of deep time
-These changes can be long, medium or short-term (or even extremely rare events)
what are some Examples of long term environmental change through time
-Solar luminosity
-Distance between the Earth and its moon (tides)
-Continental drift and plate tectonic events
-Changing atmosphere and climate change
-Milankovitch cycles
-The evolving biota
what are some Examples of short-medium term and rare events through time
-Large Igneous Provinces (LIPS)
-Short-medium term atmospheric/climate change
-Super eruptions
-Meteorite impacts
-Tsunamis
-Mass extinctions
