ch 14/15 quiz Flashcards
when was planet earth born?
4.5 bil years ago
chemical evolution conditions
- absence of free oxygen
- energy (violent storms, volcanoes, etc)
- chemicals
- time
Oparin hypothesis (Urey and Miller)
life arose gradually from inorganic molecules with “amino acids” forming first and then combining to form polymers
4 stage hypothesis for the origin of life
- synthesis of small organic molecules from abiotic chemicals
- link monomers to form polymers
- origin of self-replicating molecules for inheritance
- formation of pre-cells
macroevolution
evolution above the species level (multiplication of species, biodiversity, novelty)
nonbranching macroevolution
a pop. changes thru adaptation and original is no longer present at the end
branching macroevolution
one or more new species branch from a parent species still present at the end
pre-zygotic barriers
prevents mating and fertilized egg from forming
temporal isolation
different mating seasons
habitat isolation
physically separated species
behavioral isolation
specific traits are needed to attract mates
mechanical isolation
reproductive organs physically incompatible
gametic isolation
indvs may copulate, but gametes are incompatible and fertilization does not occur
post-zygotic barriers
mating occurs but mechanisms affect hybrid in that they cannot pass on their genetic info
hybrid inviability
hybrid dies before reaching maturity
hybrid sterility
hybrid is infertile
types of speciation are…
allopatric and sympatric
allopatric
physical barrier isolates new pop. (most likely when pop. is small)
sympatric speciation
new pop. becomes reproductively isolated (old and new species in the same place)
polyploid
2+ sets of chromosomes
occurs because of accidents during cell division and new indv cannot mate with parent pop.
gradualist model
evolutionary tree showing branches diverging gradually
punctuated equilibrium model
(more recent) species diverge is spurts bc of relatively rapid changes
biological novelty
structures we dont see in all organisms (e.g. feathers, big brain, etc)
continental drift affect on biodiversity
caused extinctions, and new opportunity for survivors
(e.g. Australia)
how many mass extinctions have occurred in the last 600 mil years
6
Gases present in earth’s early atmosphere
methane, ammonia, water vapour (NO FREE OXYGEN)
rna molecules that act like enzymes
ribozyme
significance of a molecule that can replicate itself
heritability
