Changes in the environment

Learning Target (HS-LS4-5) I can evaluate evidence that changes in the environment may lead to larger populations new species or extinction. Background A species is defined as a population or group of populations whose members interbreed and produce fertile offspring. The changes in the environment which can come from natural or human causes can contribute to the increase of a species’ populations the creation of new species or the decline and eventual extinction of a species. In this performance task you will evaluate the evidence in two cases of speciation by developing and presenting an argument visually and in a one to two page summary. The following is a brief summary of the case study of the London Underground Mosquito: Case Study – When the London underground tunnels were being constructed in the 19th century some above-ground mosquitos migrated underground and adapted to a subterranean environment. Research articles will present evidence of how the changes in their environment eventually led to a new species of underground mosquito that is unable to breed with the above-ground mosquitos. In a group you will create arguments to visually present and also develop your own argument as to how a new species of mosquitoes emerged. Guiding Question Guiding Questions: What can happen to a species if their environment changes? Task 1 – Case Study View the video below to get an introduction to how the London Underground tunnel mosquitoes differentiated: London Underground Mosquitoes or https://bit.ly/2KejAns To analyze the evidence of how this new species was formed you will be reading and analyzing news and scholarly articles about how environmental conditions affected a population of mosquitoes. After watching the video and completing both readings please answer the following questions: By Erin Blakemore SMITHSONIAN.COM MARCH 25 2016 In any given year over 1.3 billion passengers zip beneath London on its fabled Underground—the world’s first subway system. But something else lurks in the Tube’s quick-moving depths: a subspecies of mosquitoes that the BBC’s Katie Silver reports evolved inside the London Underground. The appropriately-named Culex pipiens molestus came to be over the Underground’s 150-year history.

Silver writes that it was first reported during World War II when people who used Tube stations as bomb shelters learned that the depths held plenty of pests. Among the nuisances were mosquitoes with a nasty irritating bite. In 1999 an English researcher named Katharyne Byrne went underground to investigate further. When she compared Underground mosquitoes and compared them to others found in London houses she learned that they were a distinct subspecies. After ruling out migration from elsewhere in the continent Byrne concluded that the London Underground was colonized by mosquitoes a single time then achieved “reproductive isolation” or barriers to reproduction with different species in the subway tunnels. The quick separation of mosquitoes into their own subway-dwelling subspecies is an example of quick-moving speciation (the process by which animals evolve into distinct species). Darwin’s finches in the Galapagos are often cited as an example of lightning-fast speciation—since they’re so remote they remain genetically isolated and adapt rapidly. Silver reports that some scientists doubt the mosquitoes are really unique to the underground. In 2011 for example a mysterious invasion of the mosquitoes was found in New York sewers. More up-to-date research would need to be conducted to figure it out for sure. Consider this a call to would-be researchers whose interests include both long train rides and calamine lotion: Your future in Tube-related evolutionary research could be bright indeed. The London Underground Has Its Own Mosquito Subspecies Paragraph Question/Connection Paragraph 1 How did the mosquito subspecies Culex pipiens molestus come about? When people were hiding in the tube station during world war for bomb shelter. Paragraph 2 & 3 Which evolutionary process did the new subspecies of mosquito achieve in the subway tunnels? Katharyne byrne went underground to investigate further. Byrne was colonized by mosquitoes .Then achieved reproductive isolationbarriers to reproduction with different species in the subway tunnels. Paragraph 4 Which other organism can the quick evolving mosquitoes be compared to and why? Paragraph 5 & 6 Why is there doubt that the London Underground is the only subway system that has a new subspecies of mosquitoes? The unique mosquito that lives in the London Underground When construction of the London Underground began in the 19th Century there was an unexpected consequence: evolution By Katie Silver BBC.COM 24 March 2016 Regular riders of the London Underground may bemoan the iconic and occasionally fierce tube mice. But there is another smaller animal living in the Underground that is perhaps even more at home in the subterranean network – since it actually evolved in the unique conditions of the tube environment. The London Underground mosquito is a genetically distinct subspecies. It was first reported during the Blitz of World War Two when the Tubes tunnels were used as overnight bomb shelters. Over the course of the war almost 180000 people sheltered in the Underground. They were ravaged by all sorts of insects.

“The Tube then was a very different place than it is now” says Steven Judd Head of Environment for the London Underground. With standing water and different pest controls flies ticks lice and fleas were a lot more common than they are now he says. After the war other than the odd complaint of biting made by maintenance workers the mosquito received scant attention. That was until almost 50 years later when a London-based doctoral student decided to study these subterranean biters. Katharine Byrne collected mosquitoes from seven sites across the 180km (110 mile) network. She found they were fundamentally different from their surface-dwelling relatives. While the above-ground Culex pipiens bit only birds the Culex pipiens molestus – named for their tendency to molest – had a taste for human blood. “The Culex is a very common mosquito” says biologist Bruno Gomes from the Liverpool School of Tropical Medicine. “There are hundreds or thousands of types of them and theyre not very harmful.” While they look the same as Culex pipiens the molestus mosquitoes behave in a different way. Aside from being bird-biting the above-ground midge-like flies hibernate in the winter need blood to lay their eggs and require a lot of space in which to mate. The new subspecies does not require any of these. “These differences can be interpreted in a straightforward way as adaptations to a subterranean life” wrote Byrne. Since there were no birds to feed on they began feeding on mammals mostly rats and humans. They mated in closed areas because they had to – and they lost their tendency to hibernate in winter because there are no obvious seasons underground. Byrne also found the underground mosquitoes are now so distinct they can no longer interbreed with other mosquitoes. “There are differences in both the mating behaviour and the reproductive biology” says David Reznick a biologist at the University of California in Riverside. While the surface mosquitoes form big swarms in to pair off and breed underground ones are not as abundant so it is just individuals who choose each other to mate. After the London Underground systems construction the tunnels were largely sealed off from the surface and some of the mosquitoes found themselves trapped underground. It was this physical barrier Byrne wrote that caused the divergent evolution of the two populations. It was “evolution by natural selection but in a speeded-up form” writes Tom Quinn in his book Londons Strangest Tales. With one species breeding above ground and the other below for some 100 years the stage was set for a new subspecies to evolve. Scientists say that it might have taken just a few hundred generations to do so. “People usually think of speciation as being very slow and as something you cant see happening” says Reznick. “But in this example you can sort of see it happening. Its a relatively recent phenomenon and you can see a clear start date” – when construction of the London Underground began in 1863. Not everyone is convinced though. “Its unclear if it evolved there or was brought into the Underground system… from the freight and fruit movement into the docks of London” says Judd. There is not enough research to give us an indication he adds. This might come as a surprise given that there is actually a diverse array of species available to study in the London Underground network. Mice foxes and even tortoises have been found below ground says Judd. They live amongst tunnel fluff made up of human hair and clothes fibres and tunnel dust: carbon that comes from the trains brake shoes.

“In 2015 we had no customer complaints related to biting incidents with 1.3 billion passengers travelling on the system” he says. What is clear is that the molestus mosquito is not unique to the London Underground says Gomes. It is actually found in all sorts of human underground constructions from water systems to the basements of large houses. It has been found in similar enclosed environments such as caves and sewers across Western Europe particularly temperate countries such as Spain and Portugal. It is also found in metropolitan Tokyo and in the New York subway. Still Reznick argues there are a number of genetic factors that suggest the underground mosquito first evolved in London. For instance Byrnes research involved sampling 12 surface mosquito populations near Underground sites. She compared the genetic makeup of overground and underground mosquitoes and found their alleles or gene variants to be incredibly similar. “If they [the subterranean mosquitoes] had come from Spain you would expect them to have distinct alleles to those above ground” says Reznick. The underground insects should then have been most closely related to Spains above-ground mosquitoes. But this was not the case: Londons underground and overground mosquitoes are each others closest relative. Whats more the Underground mosquitoes are all quite genetically similar. “If you have a big population of humans and then 20 go and colonise an island somewhere the colonisers will only have genes that are a small subset of the initial population” says Reznick. The underground mosquitoes are so similar to each other that it “suggests a small number of genetic individuals created this population” he says. Reznick says finding the molestus mosquito in other countries only further demonstrates how incredible the process of speciation is. It “shows that the capacity of surface mosquitoes to invade the underground exists elsewhere with the tendency to evolve other species” he says. It has also shown that speciation does not have to be a painstakingly slow process taking place over tens of thousands to hundreds of thousands of generations as Darwin first speculated. “A few hundred years in the right circumstances can form a new species” says Reznick. He points to the example of the marine stickleback fish in Anchorage Alaska which are changing genetically to adapt to freshwater environments following an earthquake in the 1960s which created new lakes there. Given that a generation in these fish lasts about a year Reznick says speciation is occurring within 50 generations. And unlike the London Underground mosquito the marine and freshwater sticklebacks do not have such a distinct physical barrier between them. “This is all happening without geographic isolation” he says. Still with no one having examined the London Underground mosquito since Byrne in the late 1990s he says work needs to be done to bring our understanding up to scratch. “The genetic tools that they were using arent the ones wed use today. The truth is – it would be nice if someone studied the mosquitoes more closely.” While Reznick has followed this speciation process in a number of organisms – from moths to flies to invasive plants – the London Underground mosquito has such a special spot in his heart that he devoted a chapter to the insects evolution in a 2010 book he wrote on the subject of Darwins 1859 classic Origin of Species. “I just love that it happened on Darwins own turf and began almost the same year he wrote his book.” The unique mosquito that lives in the London Underground Paragraph Question/Connection Paragraph 1 & 2 When was the London Underground Mosquito first discovered? Paragraph 3-5 What did researcher Katherine Byrne discover to be the key difference between the Culex pipiens and the isolated Culex pipiens molestus? Paragraph 6 & 7 What are three traits that are unique to the Culex pipiens molestus? Paragraph 8 Over time the mosquitoes developed new behaviors and features as a result of their environment. These changes are known as __________________. Paragraph 9-11 As a result of isolation over many generations the Culex pipiens molestus are no longer able to do what? Paragraph 12 The tunnels were sealed off creating a physical barrier and thereby reproductive isolation. What type of evolution occurred as a result? Paragraph 13-15 While evolution is generally a long-term process the speciation of the mosquitoes happened much more quickly. Why? Paragraph 16 & 17 What could be an alternative explanation as to the origins of Culex pipiens molestus? Paragraph 18 & 19 What other organisms have been found in the London Underground? Paragraph 20 & 21 Where else have the molestus mosquito been observed? Paragraph 22-24 Why does Reznick feel that London is the birthplace of the Culex pipiens molestus? Paragraph 25-27 Similarities between populations of underground mosquitoes suggest what? Paragraph 28-30 Fill in the blanks: “ A few hundred years in the _______ ______________ can form a new __________ ” says Reznick.

Paragraph 31 & 32 Is a physical barrier necessary to speed up the process of speciation? Which organism is proof of this? Paragraph 33-35 Why does Reznick think that it is cool that the mosquitoes originated in London? Summary Forming your Argument from Evidence In the following space summarized what you have learned about by answering the Guiding Question: What can happen to a species if their environment changes? Mastery Rubric Section Beginning Mastery (1) Near Mastery (2) Mastery (3) Learning Target: (HS-LS4-5) I can evaluate evidence that changes in the environment may lead to larger populations new species or extinction. Topic and Content Report lacks any evaluation of evidence to support claims that changes in environmental conditions result in population changes. Report provides a basic evaluation of evidence to support claims that changes in environmental conditions result in population changes. Report provides a knowledgeable and thoughtful evaluation of evidence to support claims that changes in environmental conditions result in population changes. Use of Evidence and Analysis Report lacks relevant evaluation and analysis of evidence to support claims that changes in environmental conditions result in population changes. Report provides valid analysis of provided evidence but not additional evidence necessary to support claims that changes in environmental conditions result in population changes. Report provides substantial and valid analysis of provided and additional evidence to evaluate claims to support that changes in environmental conditions result in population changes. Coherence and Organization Report lacks organized evidence and evaluations to support claims that changes in environmental conditions result in population changes. Report evidence and evaluation requires further organization or clarification to support claims that changes in environmental conditions result in population changes. Report uses coherently organized evidence and evaluation to effectively support claims that changes in environmental conditions result in population changes. Vocabulary and Academic Language Report shows little use of academic and domain language which hinders the development of evidence and analysis. -APA format is not used. Report contains academic and domain language but also has non-academic language when needed to support evidence or analysis. -An attempt is made to use APA format Report consistently makes use of accurate academic and domain language so that evidence and analysis is strengthened. -APA format is used appropriately. Exceeding Mastery (4) In addition to mastery in all categories above the report also includes 3 of the following elements: A connection to a local scientist or community a counter-argument an explanation of how the content from this report is related to content from another unit a relationship to real-world examples or applications additional sources use of advanced appropriate scientific vocabulary.

Requirements: 3-4 sentences each

What role does reproductive isolation play in the speciation of Culex pipiens molestus? What are the key adaptations unique to the underground mosquito? What were the individual causes of these adaptations? What role does reproductive isolation play in the speciation of Culex pipiens molestus? What are the key adaptations unique to the underground mosquito? What were the individual causes of these adaptations?