HW 4: CH 25 History of Life on Earth
You work for a pharmaceutical company. You are assigned to work on creating a vaccine for the disease that kills the most people annually. Which of the following diseases are you hoping to create a vaccine for?
malaria
In the origin of the eukaryotes, endosymbiosis
most likely began with a heterotrophic endosymbiont entering the cell as undigested prey or as an internal parasite.
Use the figure to determine which eon has lasted the longest to date.
proterozoic
Which Anolis lizard ecomorph has long legs?
trunk/ground
When combatting disease, which of the following is problematic because of its increasing resistance to antibiotics?
tuberculosis
Based on the information in this article, which of the following should the World Health Organization focus on to increase the quality of life for the most people?
universal health care
In order to prevent future pandemics similar to Covid-19, which of the following would be best to study?
zoonotic diseases
True or false? The evolution of different ecomorphs on the Caribbean islands is an example of stabilizing selection.
False
The study of fossils has helped geologists divide Earth's history into four eons and a number of finer-scale subdivisions: eras, periods, and epochs. Each geologic division represents a distinct timespan in the history of Earth along with characteristic life forms. Label the figure with the names of Earth's four eons. Not all labels will be used.
Origin: - Hadean - Archaean - Proterozoic - Phanerozoic Present
True or false? Convergent evolution is said to have occurred if the mouse species on two islands with similar habitats are found to have similar characteristics even though they originated from different species that did not have these characteristics.
True
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)
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.
Leaders of Afghanistan and Pakistan decide to work together to eliminate polio from its final stronghold. Which of the following would be best for them to focus on?
educating people that are against getting a vaccine
This research emphasizes the importance of regulatory processes during eukaryotic gene expression, particularly during transcription. Eukaryotic transcription requires many proteins and portions of the genome to properly function. Based on information in your textbook, select all the items that are required for eukaryotic gene transcription.
- activator - promoter - RNA polymerase - transcription factors - enhancer - mediator proteins
Surrounding the clock are colored bars denoting the start and duration of major events in Earth's history. What major events mark the Proterozoic eon? select all that apply
- origin of single-celled eukaryotes - origin of animals - origin of multicellular eukaryotes
How can gene flow, genetic drift, and natural selection all influence macroevolution? Match the words in the left column to the appropriate blanks in the sentences on the right.
1. gene flow; speciation 2. genetic drift; reproductive isolation 3. natural selection; the evolution of new morphological forms
Once the specific mutation was identified in the pelvic-reduced stickleback fish, the researchers needed to check their work. If the regulatory changes in the Pitx1 gene were due to a deletion, then a functional enhancer transgenically injected into developing fish should result in enhanced development of pelvic spines in those fish. Drag the terms on the left to the parts of the experimental design they describe on the right.
1. hypothesis 2. independent variable 3. experimental group 4. negative control group 5. dependent variable 6. conclusion
The age of fossils can sometimes be determined by radiometric dating, which is based on the constant rate of decay of radioactive isotopes. The time required for half of a radioactive isotope to decay is called the half-life of that isotope. For example, the isotope carbon-14 has a half-life of 5,730 years. Suppose it is determined that a fossilized leaf contains 12.5% of the carbon-14 that was present when the fossil formed. How old is the fossil? Express your answer numerically.
1.72x10^4 years
Using the analogy of a one-hour countdown timer, what is Earth's age at 30 minutes ago?
2.3 billion years old
Which of the cells shown in the figure are eukaryotic cells?
5, 6, and 7
Which of the following statements about adaptive radiation is correct?
Adaptive radiation occurs within a single lineage.
Use the figure to complete the paragraph about human origins. Drag the terms on the left to the appropriate blanks on the right to complete the sentences. Not all terms will be used.
Cenozoic; Phanerozoic; short; 9 minutes; 0.2 seconds
This paper illustrates the concept that science builds on itself. Through a series of experiments using a variety of techniques, the researchers pieced together an evidence-based conclusion about the Pitx1 gene.
GENOME-WIDE LINKAGE MAPPING: a single chromosome region containing the Pitx1 gene was idetified MICRO-SATELLITE MARKERS: Markers located upstream of the Pitx1 gene showed significant differences between stickleback fish with pelvic spines and stickleback fish without pelvic spines. REPORTER GENE EXPRESSION: Since EGFP expression was not observed in fish without pelvic spines, the non-coding region must contain an enhancer region for the Pitx1 gene. TRANSGENIC CONSTRUC AND FERTILIZATION: The correct DNA sequence had been identified since fish without pelvic spines injected with the Pitx1 gene developed pelvic spines. Fish that were not injected did not develop pelvic spines. SNP GENOTYPING: Repeated evolution through different small mutations of the same Pitx1 regulatory region have resulted in different populations of stickleback fish that lack pelvic spines.
Classify each event in the history of life into the appropriate eon or era. Drag each phrase to the appropriate bin.
Hadean: origin of Earth Archaean: oldest fossils of cells (prokaryotes) appear Proterozoic: oldest fossils of eukaryotic cells appear Paleozoic: first tetrapods and insects appear, the Cambrian explosion Mesozoic: dinosaurs evolve and radiate, origin of mammals Cenozoic: humans appear, major radiation of pollinating insects
Which factor most likely caused animals and plants in India to differ greatly from species in nearby southeast Asia?
India was a separate continent until 45 million years ago.
Which organisms are not examples of an adaptive radiation?
Mammals and reptiles in the post-dinosaur age
Only a very small percentage of organisms actually fossilize. Based on the information in the table below, rank the likely abundance of fossils of organisms A-E. Rank the fossils of organisms A-E from most common to least common. If two fossils have the same commonness, overlap them.
Most common fossil -organism E -organism A -organism B -organism C -organism D least common fossil
Many present-day animal phyla appeared suddenly in fossils formed 535-525 million years ago, during the Paleozoic era of the Phanerozoic eon. This period is referred to as the Cambrian explosion. Does this period mark the beginning of animal life?
No, animals originated about 700 million years ago during the Proterozoic eon.
A paleontologist finds a new tyrannosaur in a site she is excavating, and wishes to date the fossil. What is the most likely method she will use?
She will infer the age of the fossil by dating layers of volcanic rock above and below the stratum containing the fossil.
Which of the following statements supports the hypothesis of "an RNA world" on early Earth?
Some RNA molecules are important catalysts in modern cells.
What was the main selective pressure behind the evolution of different Anolis lizard species in the Caribbean?
Specific ecological niches
What was the "oxygen revolution," which took place 2.3 billion years ago?
The "oxygen revolution" was the rapid increase in atmospheric oxygen that took place 2.3 billion years ago, dooming many prokaryotic groups.
This paper illustrates the sequence of experiments performed by the researchers to piece together several pieces of evidence leading to a conclusion about the evolution of naturally occurring populations of stickleback fish that lack pelvic spines. Which choice best represents the overall conclusion of this study?
The data from the all the experiments in this study show how morphological evolution can proceed as a result of a regulatory change in important developmental control genes.
Which of the following statements about the evolution of Anolis lizards in the Caribbean islands is true?
The phylogeny of ecomorphs on a given island reveals that adaptive radiation has taken place.
Which of the following statements is accurate with regard to the Cambrian explosion?
There are fossils of animals in geological strata that are older than the Cambrian explosion.
Historically, the work of Charles Darwin and others described the larger picture of evolution. Since then, evolutionary and molecular biologists have attempted to find examples in the wild (as compared to a laboratory setting) that make connections between genetic variation and the processes of natural selection and genetic drift. How does this stickleback study help make these connections?
This research shows how mutations affecting molecular mechanisms can randomly occur in natural populations, leading to positively selected traits over a short period of time.
At the genetic level, the developmental gene Pitx1 is known to have a pleiotropic influence on the development of the pelvis, mouth, and pituitary regions of the stickleback fish. What did this study specifically identify as the primary cause of the loss of pelvic spines?
a deletion mutation in the pelvic-specific regulatory switch (enhancer) of Pitx1
