MAKE CONNECTIONS Like animals, cyanobacteria havea circadian rhythm. By analyzing the genes that maintainbiological clocks, scientists concluded that the 24-hourrhythms of humans and cyanobacteria reflect convergentevolution (see Concept 26.2). What evidence would havesupported this conclusion? Explain.

MAKE CONNECTIONS Like animals, cyanobacteria havea circadian rhythm. By analyzing the genes that maintainbiological clocks, scientists concluded that the 24-hourrhythms of humans and cyanobacteria reflect convergentevolution (see Concept 26.2). What evidence would havesupported this conclusion? Explain.

Biology (MindTap Course List)

11th Edition

ISBN:9781337392938

Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. Berg

Publisher:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. Berg

Chapter2: Atoms And Molecules: The Chemical Basis Of Life

Section: Chapter Questions

Problem 17TYU: Test Your Understanding Evaluate and Synthesize 17. EVOLUTION LINK Scientists have proposed various...

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Test Your Understanding Evaluate and Synthesize 17. EVOLUTION LINK Scientists have proposed various initiatives to detect water vapor, as well as oxygen and carbondioxide, in the atmospheres of distant planets. Which of these biosignatures (chemical markers that are evidence for life) would you consider the most fundamental indicator that life could have evolved on these planets? Explain your reasoning.
EVOLUTION CONNECTION In 1847, the German biologistChristian Bergmann noted that mammals and birds livingat higher latitudes (farther from the equator) are on averagelarger and bulkier than related species found at lower latitudes.Suggest an evolutionary hypothesis to explain this observation
MAKE CONNECTIONS The bacterium Wolbachia is asymbiont that lives in mosquito cells and spreads rapidlythrough mosquito populations. Wolbachia can make mosquitoes resistant to infection by Plasmodium; researchersare seeking a strain that confers resistance and does notharm mosquitoes. Compare evolutionary changes thatcould occur if malaria control is attempted using such aWolbachia strain versus using insecticides to kill mosquitoes. (Review Figure 28.16 and Concept 23.4.)
Cyanobacteria was responsible for the increase in oxygen levels billions of years ago. They play a decisive role in changing the earth’s environment. Explain how are Cyanobacteria related in changing the early earth’s environment which later suitable for the development of other organisms.
Molecular fossils further indicate the presence of ciliates and dinoflagellates in the emerging eukaryotic world and show that algae were expanding to become major photosynthesizers in the oceans. How can we explain this diversification?
EVOLUTION LINK Examine the cladogram in Figure 30-6a. Based on the discussion in this chapter, what were some of the types of data that biologists used to determine these phylogenetic relationships?
Thinking Critically When did the first true animals evolve? What atmospheric changes had to happen before animal life was possible? Are descendants of most of the early forms of animal life represented in the ocean today? Explain why.
1. The woolly mammoth lived from the Pliocene to the Holocene time period. Compare the temperature in °C at the start of Pliocene and the start of Holocene.
WRITE ABOUT A THEME: Organization You have seenmany examples of how form fits function at all levels of thebiological hierarchy. However, we can imagine forms thatwould function better than some forms actually found innature. For example, if the wings of a bird were not formedfrom its forelimbs, such a hypothetical bird could fly yet alsohold objects with its forelimbs. In a short essay (100–150words), use the concept of “evolution as tinkering” to explainwhy there are limits to the functionality of forms in nature.
Compare and contrast the physical and chemical conditionson Earth at the time life first arose with conditions today.From a physiological standpoint, discuss at least two reasonswhy animals could not have existed on early Earth. In whatways has microbial metabolism altered Earth’s biosphere?How might life on Earth be different if oxygenicphotosynthesis had not evolved?
Ernst Mayr defined a biological species as a population whosemembers can exchange genetic material during reproduction (seechapter 14). How does horizontal gene transfer complicate thisdefinition of species?
MAKE CONNECTIONS Human actions are causingclimate change, thereby affecting Earth’s ecosystems—few of which have been affected as greatly as those in theArctic. Hypothesize how climate change might cause evolution in arctic tundra populations. Explain