Chapter 25 Flashcards
The age of fossils can be determined using the decay of
Radioactive isotopes
Three compounds or structures found in cells that have been generated abiotically in the lab.
Organic molecules: amino acids, rna nucleotides, lipids
Polymers: proteins rna
Membrane “protocells”
Break down spontaneously over time at a constant rate
Radioactive isotopes
Life on earth probably originated how many years ago?
3.9 billion years ago
For the first 1.5 billion years, life on earth consisted of
Prokaryotic organisms
Prokaryotic organisms began to significantly increase the amount of what in the environment?
O2
Eventually some cells engulfed other cells, forming
Eukaryotic organisms
Many of the animal phyla we observed in lab first showed up in the fossil record during the
Cambrian explosion
What did the earliest land plants have a relationship with, which helped them absorb minerals and water?
Fungi
About 250 million years ago, all the major landmasses on earth were joined together in a single continent called
Pangea
The physical separation of continents since that time has promoted
Allopatric speciation
The Permian mass extinction, which wiped out 96% of marine animal species, was caused by gasses spewing from
Volcanoes
The Cretaceous mass extinction, which killed the dinosaurs, was likely caused by an
Asteroid
Many scientists argue that a sixth mass extinction is now under way, caused by
Human actions
New species evolve to fill vacant niches (positions in the ecosystem)
Adaptive radiation
