Chapter 25 Flashcards
Earth’s early atmosphere had little oxygen and likely contained water vapor and chemicals released by volcanic eruptions, give examples of the gasses released by these volcanic eruptions
Nitrogen, Carbon dioxide, Methane, Ammonia, Hydrogen
In the 1920s, they independently hypothesized that the early atmosphere was a reducing environment
Oparin and Heldane
In 1953, They conducted lab experiments demonstrating that the abiotic synthesis of organic molecules in a reducing atmosphere was possible
Stanley Miller and Harold Urey
Areas on the seafloor where hot water and minerals gush from Earth’s interior into the ocean
Hydrothermal Vents
Release water with high pH (9-11) and warm water (40-90°C)
Alkaline Vents
Have been produced spontaneously from simple molecules
RNA Monomers
Polymerize when they are concentrated on hot sand, clay, or rock
Small Organic Molecules
Replication and metabolism are key properties of life and may have appeared together in?
Protocells
May have formed from fluid-filled vesicles with a membrane-like structure
Protocells
a soft mineral clay common on early Earth, greatly increases the rate of vesicle formation
Montmorilonite
The first genetic material was probably?, not DNA
RNA
exhibit simple growth, reproduction, and metabolism
can “reproduce” on their own, and they can increase ins size without dilution of their contents
can absorb montmorillonite particles, including on which RNA and other organic molecules have become attached
Vesicles
are deposited into layers called strata and are the richest source of fossils
Sedimentary Rocks
have been found to catalyze many different reactions
Ribozymes
The fossil record is biased in favor of species that?
- existed for a long time
- were abundant and widespread
- had hard parts, such as shells or skeletons
The age of a fossil can be determined using?
Radiometric Dating
the time required for half the parent isotope to decay
Half-life
Radiocarbon dating can be used to date fossils up to how many years old?
75,000 years old
The age of some fossils can be estimated by measuring the ratio of the radioactive isotope ________ to the stable isotope _______
Carbon 14 and 12
Mammals belong to the group of animals called?
Tetrapods
is divided into the Hadean, Archaean, Proterozoic, and Phanerozoic eons
Geologic Records
The geologic records is divided into 4 periods what are these?
Hadean, Archaean, Proterozoic, and Phanerozoic eons
The oldest known fossils
rocks formed by the accumulation of sedimentary layers on bacterial mats
Date back to 3.5 billions years ago
Stromatolites
were Earth’s sole inhabitants for more than 1.5 billion years
Prokaryotes
O2 accumulated gradually in the atmosphere from about how many years ago? and then rapidly shot up to what percentage to the present level
2.4-2.7 billion years ago, 1%-10%
caused the extinction of many prokaryotic groups
Oxygen Revolution
The oldest fossils of eukaryotic cells date back to how many years ago?
1.8 billion years ago
when a prokaryotic cell engulfed a small cell that would evolve into a mitochondrion
Endosymbiosis
is a cell that lives within a host cell
Endosymbiont
supposes that mitochondria evolved before plastids through a sequence of endosymbiotic events
Serial Endosymbiosis
likely descended from bacterial cells; the original host is thought to be an archaean or close relative
Mitochondria and Plastids
were an assemblage of larger and more diverse soft-bodied organisms that lived from 635 to 541 million years ago
Ediacaran Biota
refers to the sudden appearance of fossils resembling modern animal phyla in the Cambrian period (535 to 525 million years ago)
Cambrian Explosion
began to colonize land about 500 million years ago
Fingi, Plants and Animals
are the most widespread and diverse land animals
Arthropods and Tetrapods
evolved from lobe-finned fishes around 365 million years ago
Tetrapods
According to this theory, Earth’s crust is composed of plates floating on Earth’s mantle
Theory of plate tectonics
At times, the rate of extinction has increased dramatically and caused a?
can change the types of organisms found in ecological communities
Mass extinction
defines the boundary between the Paleozoic and Mesozoic eras 252 million years ago
Permian Extinction
A number of factors might have contributed to the Permian mass extinction, what are these?
Extreme Volcanism, Huge amounts of CO2, Anoxomic Conditions
occurred 66 million years ago
More than half of all marine species, many families of terrestrial plants and animals, and all of the dinosaurs, except birds, went extinct during this event
Cretaceous Mass extinction
Data suggest that a sixth, mass extinction is likely to occur unless dramatic action is taken, what is this mass extinction?
Human-cause
