BSC 2011: Ch 25
The Mesozoic era is the age of ___
reptiles
RNA catalysts are called ___.
ribozymes
The first genetic material on Earth was probably ________.
self-replicating RNA molecules
Single-celled prokaryotes had the Earth to themselves for approximately __________.
1.5 billion years
A living organism contains the most common carbon isotope, carbon-___, as well as a radioactive isotope, carbon-___. When the organism dies, it stops accumulating carbon, and the amount of carbon-___ in its tissues does not change over time. Thus, by measuring the ratio of carbon-14 to carbon-12 in a fossil, we can determine the fossil's ___.
12; 14; 12; age
The Mesozoic era began approximately _____ million years ago.
251
Which organisms are not examples of an adaptive radiation?
Mammals and reptiles in the post-dinosaur age
___ ___ can also alter ecological communities by changing the types of organisms residing there. Once an evolutionary lineage disappears, it cannot reappear.
Mass extinctions
Dinosaurs went extinct during the _____.
Mesozoic
Flowering plants first appeared during the _____.
Mesozoic
The early atmosphere may not have been as reducing as originally postulated by Haldane, Oparin, Miller, and Urey. In light of current thinking about the composition of the early atmosphere, what is regarded as a likely place for the abiotic synthesis of organic molecules to have occurred?
Near volcanoes
What evidence most strongly suggests that an impact by an asteroid or meteorite may have caused the extinction of the dinosaurs?
Sedimentary rocks contain a layer of iridium, a mineral uncommon on Earth.
Which of the following is the correct ordering of divisions of the geologic record from largest to smallest?
eon, era, period, epoch
What was one ecological change that occurred following the Permian mass extinction?
The percentage of marine predators increased.
Reinforcement is also called
disruptive selection
The term ___ refers to a cell that lives within another cell, called the ___ ___.
endosymbiont; host cell
If the wings of extant flying birds originally arose as thermoregulatory devices in ancestral reptiles, then the bird wings could be accurately described as __________.
exaptations
Without a ___ environment, organic molecules and dust in the atmosphere may not have been able to persist for very long before being broken down.
reducing
Selection for species recognition traits is called
reinforcement
Fossilized stromatolites __________.
resemble structures formed by bacterial communities that are found today in some warm, shallow, salty bays
The Miller and Urey abiotic synthesis experiment (and subsequent, similar experiments) showed that __________.
simple organic molecules can form spontaneously under conditions like those thought to prevail early in Earth's history
Reinforcement is a specific type of
natural selection
What is thought to be the correct sequence of these events, from earliest to most recent, in the evolution of life on Earth? 1. origin of mitochondria 2. origin of multicellular eukaryotes 3. origin of chloroplasts 4. origin of cyanobacteria 5. origin of fungal-plant symbioses
4, 1, 3, 2, 5
The Precambrian time began at least _____ million years ago.
4,600
Which of the cells shown in the figure are eukaryotic cells?
5, 6, and 7
In each mass extinction, __% or more of the marine species comprising the fossil record became extinct.
50%
The Cenozoic era began approximately _____ million years ago.
65
What is genetic drift? -The physical splitting of a habitat -A change in allele frequencies caused by random events -The motion of continental plates over time -The production of an evolutionarily independent group of organisms
A change in allele frequencies caused by random events
Which of the following statements about adaptive radiation is correct?
Adaptive radiation occurs within a single lineage.
Why are the large finches now living on the Galápagos Islands different from the original source population from a nearby island? -Natural selection favored individuals that were more fit in the new environment. -Genetic drift occurred in the two populations. -All three answers are correct. -The separation of habitats reduced gene flow between the populations.
All three answers are correct; Physical isolation, natural selection, and genetic drift are all events that lead to speciation.
Which of the following would not have been a consequence of tectonic plate movements bringing previously separated landmasses together in the formation of the supercontinent of Pangaea about 250 million years ago?
Allopatric speciation increased.
_____ were the dominant vertebrate life form during the Paleozoic era.
Amphibians
What are the three eons and how long did they last?
Archaean and Proterozoic together lasted ~4 billion years; Phanerozoic lasted ~ half billion years
Although they originated around 180 million years ago, mammals underwent an adaptive radiation starting approximately 65 million years ago. Why?
Between 180 and 65 million years ago, mammals were outcompeted by the well-established dinosaurs.
What were the two major "problems" that had to be solved before plants, animals, and fungi could move into terrestrial habitats?
Reproduction and prevention of dehydration
We are living during the _____era.
Cenozoic
The original atmosphere of Earth had little oxygen. What was the likely first source of oxygen that led to an oxygen atmosphere?
Cyanobacteria
___ can be replicated more accurately than ___.
DNA; RNA
_____ were the dominant vertebrate life form during the Mesozoic era.
Dinosaurs
The evolution of different ecomorphs on the Caribbean islands is an example of stabilizing selection.
False
True or false? The last ice age produced many different species mainly because populations dispersed and colonized new habitats.
False, The last ice age produced many different species mainly because of vicariance events; the glaciers physically separated populations from each other.
How many mass extinctions are documented in the fossil record over the past 500 million years, from the Paleozoic to the Cenozoic era?
Five
Adaptive radiations can be a direct consequence of four of the following five factors. Select the exception.
Genetic drift
Which factor most likely caused animals and plants in India to differ greatly from species in nearby southeast Asia? -Life in India was wiped out by ancient volcanic eruptions. -India is in the process of separating from the rest of Asia. -The climates of the two regions are similar. -India was a separate continent until 45 million years ago.
India was a separate continent until 45 million years ago.
Why is the four-stage hypothesis for the abiotic origin of life useful?
It leads to predictions that can be tested.
A species may become extinct for what two main reasons
Its habitat may be destroyed, or its environment may change in a manner unfavorable to the species.
Bony fish first evolved during the _____ .
Paleozoic
Most modern animal phyla evolved during the _____ era.
Paleozoic
Reptiles first appeared during the _____ era.
Paleozoic
Seed plants first appeared during the _____.
Paleozoic
The correct order of the geologic eras, from most ancient to most recent, is __________.
Paleozoic, Mesozoic, and Cenozoic
Mammals originated following the ___ period.
Permian
Marine biodiversity increased following the ___ mass extinction.
Permian
Which eons encompasses most of the time animals have existed on Earth?
Phanerozoic
Animals first appeared during the _____.
Precambrian
Life arose during the _____.
Precambrian
The first prokaryotic cells appeared during the _____.
Precambrian
Why is RNA, rather than DNA, thought to have been the first genetic material?
RNA can also function as a catalyst.
Some ribozymes can make complementary copies of short pieces of ___, provided that they are supplied with ___ ___ ___
RNA; nucleotide building blocks.
Which of the following statements about reinforcement is true? -Reinforcement decreases the morphological difference between two incipient species. -Reinforcement is also called dispersive selection. -Reinforcement increases the number of intermediate phenotypes. -Reinforcement is a type of natural selection.
Reinforcement is a type of natural selection.
Which of the following is not a unique anatomical feature of mammals that can be recognized in the fossil record?
Temporal fenestra
Which of the following is a true statement about the current status of Earth's biodiversity?
The current rate of extinctions is as high as 1,000 times the typical rate seen in the fossil record.
Which of the following is a true statement concerning the history of Earth's biological diversity?
The majority of species that ever lived are now extinct.
What is true of the Cambrian explosion? -Only the fossils of microorganisms are found in geological strata older than the Cambrian explosion. -The Cambrian explosion is evidence for the instantaneous creation of life on Earth. -There are fossils of animals in geological strata that are older than the Cambrian explosion. -The Cambrian explosion marks the appearance of filter-feeding animals in the fossil record.
There are fossils of animals in geological strata that are older than the Cambrian explosion.
What evidence supports the hypothesis that mitochondria and plastids evolved from prokaryotic endosymbionts?
They have a single circular chromosome similar to bacterial chromosomes; their ribosomes are more like prokaryotic ribosomes than eukaryotic ribosomes
Prior to the Cambrian explosion, all large animals had what characteristic in common?
They were all soft-bodied.
You are watching a movie in which one of the characters excitedly claims to have found human remains in Asia dated at 10 million years old. The date was obtained by carbon-14 dating. What is your reaction?
This can't possibly be true because carbon-14 dating can only be used back to about 75,000 years.
True or false, double-stranded DNA is a more stable repository for genetic information than is the more fragile single-stranded RNA.
True
Which of the following is an internal structure that appears in eukaryotic cells and is also present in more ancient prokaryotic cells?
Vesicles
A genetic change that caused a certain Hox gene to be expressed along the tip of a vertebrate limb bud instead of farther back helped make possible the evolution of the tetrapod limb. This type of change is illustrative of __________.
a change in a developmental gene or in its regulation that altered the spatial organization of body parts
The fossil record is __________.
biased in favor of species that existed for a long time
The ratio of carbon-14 to carbon-12 in a fossil can be used to determine the age of the fossil because __________.
carbon-14, unlike carbon-12, decays at a continuous rate after the death of an organism
An early consequence of the release of oxygen gas by plant and bacterial photosynthesis was to _____.
cause iron in ocean water and terrestrial rocks to rust (oxidize)
Pangaea's interior was___ and ___, probably an even more severe environment than that of central Asia today.
cold and dry
As landmasses came together, ocean basins became ___, which lowered ___ ___ and drained ___ ___ seas.
deeper; sea levels; shallow coastal
The lower jaw is composed of one bone, the ___, in mammals but is composed of several bones in other tetrapods.
dentary
In living mammals, the ___-___ hinge is the only hinge between the lower and upper jaws.
dentary-squamosal
During the origin of the eukaryotic cell, it is thought that engulfed bacteria -did not initially have a mutually beneficial relationship with their hosts, but later evolved one. -always had a mutually beneficial relationship with their hosts. -were always harmful to their hosts. -had a mutually beneficial relationship with their hosts initially, but later evolved to become harmful to their hosts.
did not initially have a mutually beneficial relationship with their hosts, but later evolved one.
In the species selection model, __________ is to macroevolution as __________ is to microevolution.
differential speciation success; differential reproductive success
Mammals have a unique set of three bones—the___, ___, and ___—that transmit sound in the middle ear, whereas other tetrapods have only one such bone, the stirrup.
hammer, anvil, and stirrup
The teeth of mammals are differentiated into ___ (for tearing), ___ (for piercing), and the multi-pointed ___ and ___ (for crushing and grinding).
incisors, canines, premolars and molars
Macroevolution differs from microevolution in that macroevolution __________.
includes broad evolutionary changes above the species level
Stromatolites are formed by ___ organisms. There is nothing ___ about them.
living; abiotic
Reinforcement increases ___ divergence between two new species, ensuring they will remain reproductively isolated
morphological
In the origin of the eukaryotes, endosymbiosis -describes the engulfing of a photosynthetic bacterium that ultimately gave rise to mitochondria. -is thought to explain the origin of the nucleus. -most likely began with a heterotrophic endosymbiont entering the cell as undigested prey or as an internal parasite. -most likely began with the endosymbiont entering the host cell through the endomembrane system.
most likely began with a heterotrophic endosymbiont entering the cell as undigested prey or as an internal parasite.
All ___ organisms have DNA as their genetic material.
multicellular
Some evidence suggests that the early atmosphere was made up primarily of ___ and ___ ___ and was neither ___ nor ___
nitrogen and carbon dioxide; reducing nor oxidizing.
The carbon-14 that an organism contains at the time of its death slowly decays into another element, ___.
nitrogen-14.
RNA and DNA are comprised of a similar set of ___ ___ ___.
nucleotide building blocks
Retention of juvenile body features into sexual maturity is referred to as the presence of __________.
paedomorphosis
Synapsids, from which mammals originated, also had an opening called the ___ ___ behind the eye socket. Powerful ___ ___ for closing the jaws probably passed through the this. Over time, this opening enlarged and moved in front of the hinge between the lower and upper jaws, thereby increasing the power of and precision with which the jaws could be closed.
temporal fenestra; cheek muscles
The amphibians, reptiles, and mammals comprise which group?
tetrapods
Perhaps the first organic compounds formed near ___ or ___
volcanoes or deep-sea vents
