Flashcards in Chapters 15-17 Deck (98)
when did earth form
about 4.6 billion years ago
how first life may have evolved
1. abiotic synthesis of small organic molecules, such as amino acids and nitrogenous bases
2. joining of these small molecules into polymers, such as proteins and nucleic acids
3. packaging of these molecules into “protocells”
4. origin of self-replicating molecules that eventually made inheritance possible
what does O2 tend to do?
As a strong oxidizing agent, O2 tends to disrupt chemical bonds.
next 3 stages of life
1. Abiotic synthesis of polymers
2. Formation of protocells
3. Self-replicating RNA
evolutionary change above the species level. encompasses...
-the origin of a new group of organisms through a series of speciation events and
-the impact of mass extinctions on the diversity of life and its subsequent recovery.
-is based on the decay of radioactive isotopes (unstable forms of an element)
-can date rocks and fossils.
-carbon-14 decays to another element
the theory that Earth’s crust is divided into giant, irregularly shaped plates that essentially float on the underlying mantle.
linked to the effects of extreme volcanic activity.
included most dinosaurs. may have been caused by the impact of an asteroid.
periods of evolutionary change in which many new species evolve from a common ancestor.
combines evolutionary and developmental biology.
branch of biology concerned with identifying, naming, and classifying species.
two-part scientific name
The evolutionary history of a species or group of species
a discipline of biology that focuses on
-determining their evolutionary relationships.
a hypothesis of evolutionary relationships.
Similarity due to convergent evolution
groups organisms by common ancestry.
monophyletic group that consists of an ancestral species and all its evolutionary descendants—a distinct branch in the tree of life.
Cladistics two main types of characters
1. A shared ancestral character
2. A shared derived character
shared ancestral character
common to members of a particular clade, but originated in an ancestor that is not a member of the clade.
shared derived character
common to members of a particular clade and is not found in its ancestors.
the adoption of the simplest explanation for observed phenomena.
uses DNA or other molecules to infer relatedness.
a method that estimates the time required for a given amount of evolutionary change.
Earliest form of life
prokaryotes about 3.5 to 2 billion years ago
origin of single-celled eukaryotes
1.8 billion years ago. originated when prokaryotic cells became capable of aerobic respiration or photosynthesis
origin multicellular eukaryotes
1.2 billion years ago. larger organisms 600 million years ago.
earth's eon history
hadean, archaean, Proterozoic, and Phanerozoic