Ch. 18: Coevolution

The mutualistic relationship between Glycine max and Bradyrhizobium japonicum provides benefits to both species. Describe those benefits.

- G. max receives organic nitrogen from B. japonicum - B. japonicum receives carbohydrates and other energetic resources from G. max

Human adults have not always been able to digest lactose, the primary carbohydrate of cow's milk, because of reduced production of lactase (the enzyme that breaks down milk) soon after weaning age. Because of the development of agriculture systems, a series of events occurred that led to the gene-culture evolution of lactose tolerance in humans. Place events in their correct historical order.

1. Domestication of cattle 2. Fermentation of milk products (cheese, yogurt) 3. Mutation of LCT gene 4. Rise in frequency of LCT mutation

Antagonistic coevolution

An evolutionary relationship in which evolutionary changes in each species decrease the fitness of the other species.

Cospeciation

Concurrent occurrence of speciation in both partners of an interspecific mutualism

Pthirus pubis

Louse species that jumped to humans from gorillas

In the oak-hickory forests of the Ozark region of Missouri and Arkansas, several native bee pollinators belonging to the same genus pollinate several species of plants also belonging to the same genus. An entomologist studying this system in the early 1900s documented that many of these pollinators favored single species of plants when visiting flowers. In 2010, a graduate student decided to revisit this plant-pollinator system and discovered that some of the bee species had apparently gone extinct. Further observation indicated that the extinct bees' preferred plant species were either in decline or locally extinct. What type of coevolutionary system is this?

Obligate mutualism - It appears the bees were unable to survive without their preferred plants and the plants were unable to survive without their pollinator, which is classic obligate mutualism

How did the cultural transmission of song by G. fortis and G. scandens impact gene flow between the two species?

The Grants found that females only mated with males who sang the song typical of their species, greatly reducing gene flow via hybridization - Darwin's finches continue to provide us with insights into evolution, with this research illustrating the role of cultural transmission in inhabiting gene flow between species

The mutualism between Hardwicke's woolly bat and the pitcher plant Nepenthes hemsleyana has been well documented. In a dense forest with other roost choices, how does this rare plant ensure that the bats are able to find it and continue to receive the benefit of additional nitrogen, the limiting nutrient for plant growth?

The plants have exceptionally good reflective structures that help bats use echolocation more effectively to find them.

Examples of predator-prey coevolution

- A species of moth preyed on by bats using echolocation evolves the ability to use ultrasonic detection of bats to evade them, increasing the survival of moths with this ability - The mouth parts of beetles are especially adapted for chewing; many beetles chew up flowers and eat pollen of their host plants - Monarch butterfly larvae feed exclusively on milkweed plants that produce poisonous glycosides to evade predation by other animals

Coevolution can take many forms and can be beneficial or detrimental to the species involved. In 2013, Vannette and her team manipulated the interaction between hummingbirds and a hummingbird-pollinated shrub, Mimulus aurantiacus. What pairs accurately describe this example of diffuse coevolution based on their results?

- Antagonistic relationship between Gluconobacter bacteria and hummingbird by reducing nectar consumed by hummingbirds, reducing seed sets, resulting in lower pollination success - Mutualism between hummingbirds and M. aurantiacus

Context: In his 2005 and 2008 studies, Kuchta examined mimicry and coevolution in a salamander-newt system where one palatable species mimics another unpalatable species. Fill in the blank: The yellow-eyes salamander, Ensatina eschscholtzii xanthoptica, has _______ coloring to warn predators to stay away even though it is _______. The California newt, Taricha torosa, produces a _______, making it _______ to predators. This type of mimicry is _____ as opposed to _______, in which both species would be palatable.

- Aposematic - Palatable - Neurotoxin - Unpalatable - -

What statements describe the coevolutionary relationships between the imperial blue butterfly (Jalmenus evagoras) and the ant Iridomyrmex anceps?

- Butterfly larvae and pupae secrete sugary nectar consumed by ants - Ants protect the butterfly larvae and pupae from predators - Butterfly larvae not tended by ants grow larger than larvae tended by ants - Ants are more readily detected by their own predators

Examples of obligate mutualism

- Coral reefs are comprised of coral polyps that have zooanthellae living within them. Warming oceans cause the coral polyps to expel the zooanthellae. Without them, the coral bleaches and then ultimately dies. - Several species of yucca plants are pollinated by only one species of yucca moth. In turn, the moth uses the flowers to lay their eggs. Without the moth, the yucca plants can't reproduce. With the plant's seeds, the moth's caterpillars do not have a food source. -

Examples of mutualism

- Leguminous plants (think peas and beans) typically have nitrogen fixing bacteria in the roots and root hairs of the plant. The bacteria fixes nitrogen and converts it to ammonia, which is a form usable to the plant. The bacteria obtains carbohydrates from the plant for growth - Cows are ruminants, which means their stomachs have a series of compartments that enable them to digest the plants they eat. Bacteria in the rumen (the largest compartment) help to digest and ferment the cow's food, making it digestible for the cow while benefitting from the food source and warm, moist environment.

Context: Cospeciation in Glochidion trees and Epicephala moths comprises a system of 300 species of Glochidion trees distributed across Asia, Australia, and Polynesia. The exact number of Epicephala moth species is not known, but evidence suggests it is likely large. Fill in the blank: This system is an example of ________, where one partner can only survive and reproduce successfully in the presence of the other. The female moth transports _______ between the Glochidion trees and lays her eggs in the flower's ____. The moth _______ feed on _______, destroying a small number in the process.

- Obligate mutualism - Pollen - Style - Larvae - Developing seeds

Fill in the blank: The study of several fungal gardening species has revealed that ants provide a _______ for fungi to grow, and they also protect the fungi from _____ by using _______ to produce _____ to kill parasites

- Safe haven - Disease - Pseudonocardia and Streptomyces - Antibiotics

Why did the rate of flower capsule abortion increase in woodland star populations where multiple pollinators were present in addition to the moth Greya politella?

- The plant aborted flower capsules with moth eggs because moth larvae eat seeds - Having other pollinators assured reproductive success for woodland star - Costs of having the moth pollinator outweighed the benefits, favoriting an antagonistic response

Predator-prey relationships often evolve into an evolutionary arms race where selection favors a predator that can more efficiently capture prey. However, it also favors prey that can escape the new adaptation in the predator. Your text describes the fossil record of the evolutionary arms race between Sinistrofulgur and Mercenaria. Describe this evolutionary arms race in the order in which they were observed.

1. Sinistrofulgar mounts Mercenaria, using shell to chip at bivalve 2. Mercenaria shell size increases 3. Sinistrofulgar increases in size 4. Sinistrofulgar changes attack position

Diffuse coevolution

A coevolutionary relationship that involves more than two species that affect one another

Obligate mutualism

A mutualism in which each partner requires the other for successful survival and/or reproduction

Although there is no set specific pathway for the development of mutualism, this type of interaction between species has a long and diverse evolutionary history. This chapter highlighted many examples. Match the partnership with its corresponding mutualism. A. Mitochondria B. Pollination C. Mycorrhizae D. Chloroplasts E. Fungus gardens

A. Eukaryotes/Bacteria B. Plants/Animals C. Plants/Fungi D. Eukaryotes/Cyanobacteria E. Ants/Fungi

The studies of ectoparasitic feather lice and their pigeon and dove hosts revealed a pattern of body size matching between the hosts, enabling the lice to evade the preening behavior of their host species. Which statement accurately describes the mechanism of coevolution in these species?

After a speciation event in their host species, the lice are constrained to remain on their original host to survive. When selection acts on their host, the lice also experience selection in new ways. - If the lice were to switch to the new host, they would likely becomes susceptible to predation by that host.

The moth Greya politella is a pollinator of the Lithophragma parviflorum (woodland star). Given what you have learned about the mosaic coevolution that occurs between these two species, what would likely happen to G. politella if L. parviflorum went extinct?

G. politella would also likely go extinct as it is completely reliant on L. parviflorum as its host - L. parviflorum is the sole host of G. politella, so losing this host would likely lead to the end of G. politella

The theory of mosaic coevolution describes another way in which coevolution can lead to diversity. Rather than looking at specific outcomes between a pair of species or group of species, what does it examine?

Geographic variation in coevolutionary outcomes - This type of coevolution can result in mutualistic relationships in one geographic area and antagonistic relationships in another

The moth Greya politella is a pollinator of the Lithophragma parviflorum (woodland star). Given what you have learned about the mosaic coevolution that occurs between these two species, what would likely happen to L. parviflorum if G. politella went extinct?

L. parviflorum would continue to survive, but its range would be reduced as a result of losing G. politella as a pollinator in areas where it was the only pollinator

Pediculus humanus

Louse with two ecotypes that colonize head and clothing

Batesian mimicry

Mimicry in which a palatable species resembles an unpalatable species

Mullerian mimicry

Mimicry in which unpalatable species resemble one another

Lichens can be observed growing on rocks and trees all over the planet, even helping to build soil in areas where soil has been removed or covered, such as occurs with a lava flow. Lichens are an association between a fungal species and either a photosynthetic algae or cyanobacteria. Each species receives benefits from the other and neither species can survive without the other. What is this type of coevolution interaction called?

Mutualistic coevolution - This is a clear example of each species benefiting the other to the extent that they must live together to survive

Mosaic coevolution

When two species interact mutualistically in some communities but antagonistically in others

Mutualism benefits both species involved, but if one of the participants were to find a way to cheat (receive the benefit while not providing a benefit), it would give the cheater an evolutionary advantage, although that advantage may only be short term. Researchers studying the mutualism between Glycine max (soybean) and rhizobial bacterium (Bradyrhizobium japonicum) forced B. japonicum to "cheat" by creating a nitrogen-free atmosphere in one of their treatments. What were the results?

The plants differentially allocated O2 to nodules with nitrogen-fixing bacteria over nodules with bacterial cheaters - By limiting the O2 available to the cheating bacteria, the plants reduced the growth rate of the cheating bacteria population, therefore punishing them for cheating