System Earth Ch 13 Flashcards
What are our main data sources for biodiversity?
fossil records, which are grouped by body shape
what do biodiversity records show?
that biodiversity is increasing but with its fluctuations.
important diversity events
Cambrian explosion
Stable Ordovician then dropped
drop in late devonian
late permian - 95% of species extinct
problems with fossils for biodiversity?
fairly unreliable, they could have been destroyed etc.
taxonomy
domain, kingdom, phylum, class, order, family, genus, species.
evolution
the change from one generation to the next of inherited characteristics of a population of organisms.
adaptation
changes in the body to fit the location
natural selection
a principal driver of evolution
origination
when evolution goes so far that the species is unable to breed with the original species, it becomes a new species.
extinction
the loss of all individuals of a certain species.
largest mass extinction
permian 252 M y ago
Siberian volcanic eruption
massive basalt flow
Siberian traps
anoxic conditions
toxic hydrogen sulphide released?
K-T mass extinction
dinosaurs
65 M y ago
75% species extinct
possibilities for K-T extinction
meteorite impact
volcanic eruption
sea level
iridium
levels were very high around K-T extinction but there are many possibilities for this, including a 65 M y cycle
evidence K-T
charcaol from fires
dead plants
high temp impacts
clay composition
fossil locations
no preferential survival
what is the name of THE crater?
the Chicxculub crater
Environmental consequences of K-T extinction
equator to pole gradient decrease
destroyed stratospheric ozone from NO
acid rain
global average temp rises by 10-15K
delayed reestablishment of the active oceanic biological pump for the next hundreds of thousands of years
impacts of extraterrestrial influences
comets - dirty snowballs
asteroids - minerals and metals
periodicity of extinctions?
roughly 62 million years
Q1. how to deal with incomplete records?
statistically alter the data to correct for discrepancies in fossil availabitility.
Q2. processes that cause evolution?
natural selection (evolution)
mutation
Q3. How does fossil diversity change over time?
some records get destroyed
Q4. explanations for K-T extinction
volcanic eruptions, meteorite, sea level change
Q5. environmental consequences of meteorite impact?
world goes to hell: fires, acid rain, no ozone, NO soars
Q6. Other mass extinctions?
volcanoes, sea level change etc.
