exam 3: early life Flashcards
Which of the following is not a shared property of all living things?
all living things are capable of being generated from nonliving matter and energy.
When life first evolved, ocean temperatures were ________ and there was ________
atmospheric oxygen.
hotter, no
Which of the following is not currently thought to be a source of molecules in the “prebiotic
soup”
DNA
The Miller–Urey experiment is significant because it produced the first scientific evidence that
conditions on earth 4 billion years ago could in principle produce amino acids
what is/ was LUCA?
a population of life forms that was the last common ancestor of life on earth today
Ribozymes are
catalytically active RNA molecules or RNA–protein complexes, in which solely the RNA provides catalytic activity
-RNA enzymes
Which of the following is a reason DNA is favored over RNA as genetic material
DNA is more stable and this is a more efficient transmission system
Why did Spiegelman conduct serial transfers in the experiment illustrated in the figure?
each serial transfer is equivalent to a generation and thus provided an opportunity to study natural selection over time
the two major cell types currently known are
prokaryotes and eukaryotes
Molecular mutualism is
an interaction between molecules that positively impact the replication of each
How has the role of horizontal gene transfer (HGT) in evolution changed over time?
early life forms had modular genomes for which HGT played a large role in adaptation. This role has decreased over time
If horizontal gene transfer was predominant in early evolution, how would this affect our
ability to reconstruct the tree of life?
Horizontal gene transfer blurs the concept of species, making it difficult to delineate ancestral species
How do comparative data on the genes of extant species help us make estimates of what
happened before the phylogenetic event horizon?
common functional genes imply the minimal characteristics of early cells
Why does the theory of evolution not explain the origin of life
the theory of evolution explains how life diversified after its origin and does not address the origin of life itself
How did the discovery of ribozymes affect our understanding of the evolution of proteins and
nucleic acids?
The discovery of ribozymes demonstrated that enzymes did not have to be proteins, and RNA enzymes (ribozymes) can be both information carrier and enzymatic molecule.
