Origin of Species Beak of the Finch Film Guide Educator

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Film Guide, The Origin of Species The Beak of the Finch Educator Materials. CURRICULUM CONNECTIONS,Standards Curriculum Connection. NGSS 2013 LS2 A LS3 B LS4 B LS4 C,AP Bio 2015 1 A 1 1 A 2 1 A 4 1 B 2 1 C 1 1 C 2. IB Bio 2016 5 1 5 4 C 1,AP Env Sci 2013 II C,IB Env Systems and Societies 2017 3 2. Common Core 2010 ELA RST 9 12 4 WHST 6 12 9 MP2,Vision and Change 2009 CC1 CC5.
PRIOR KNOWLEDGE,Students should, have a basic understanding of natural selection evolution and adaptation. be familiar with the concept that organisms occupy specific niches in their environments and. know that genes and their respective traits are inherited and that some traits provide organisms with a. greater chance to survive and reproduce,PAUSE POINTS. The film may be viewed in its entirety or paused at specific points to review content with students The table. below lists suggested pause points indicating the beginning and end times in minutes in the film. Content Description Review Questions,1 0 00 5 36, The 13 species of finches in the Gal pagos have different What evidence did. beaks adapted to different diets scientists use to. DNA evidence indicates that the Gal pagos finch species determine that all 13. are all more related to one another than any one is to a species of finches on the. species on the mainland they all evolved from one Gal pagos have one. ancestral species common ancestor, 2 5 37 11 08 Traits like the size and shape of beaks can change when How did the population of. the environment and thus the food supply changes medium ground finches. Habitats and ecological niches are constantly changing on the island of Daphne. In 1977 as a result of drought large seeds were abundant Major change as a result. and birds with large strong beaks had a competitive of environmental. advantage Over generations the average beak depth changes. changed Does evolution happen, In 1983 abundant precipitation allowed vines to flourish quickly or slowly.
During the 1985 drought smaller seeds were more,abundant so that birds with smaller beaks had a. competitive advantage survived well and their offspring. had smaller beaks, Evolutionary change can occur rapidly in only a few. generations if there is genetic variation among individuals. in a population and if natural selection acting on this. variation is strong, 3 11 09 15 45 Species are defined as populations whose members do What is the definition of a. not interbreed with members of other populations species. Reproductive isolation can result in speciation What two characteristics. Song and appearance both played a role in keeping played a role in. members of different species from mating with each reproductively isolating. other ground finches, It is likely that a finch species arrived on one island from How did one ancestral. The Origin of Species Revised March 2018,www BioInteractive org Page 2 of 12.
Film Guide, The Origin of Species The Beak of the Finch Educator Materials. the mainland then as descendants populated other population give rise to. islands their traits changed over time If the changes many species each with. included traits in mating they became distinct species different adaptations. BACKGROUND, During Charles Darwin s journey on HMS Beagle from 1831 to 1836 he spent five weeks on the Gal pagos Islands. in 1835 Although his visit was short the observations Darwin made and what he concluded about how evolution. works made his trip one of the most famous events in the history of science. When Darwin first encountered the finches he collected and categorized them into three distinct groups. blackbirds wrens and finches After he returned to England he presented his specimens to one of Britain s. leading ornithologists John Gould Gould identified all the birds as belonging to a single group based on their. anatomy and colorings rather than several groups as Darwin had thought Darwin was struck by the fact that. although the birds were all finches according to Gould the sizes and shapes of their beaks were remarkably. different as different as those of birds from different taxonomic groups on various continents In a particularly. evocative phrase in his book The Voyage of the Beagle Darwin wrote Seeing this gradation and diversity of. structure in one small intimately related group of birds one might really fancy that from an original paucity of. birds in this archipelago one species had been taken and modified for different ends. His discovery of the finches along with other evidence he had gathered during his voyage all pointed toward one. conclusion All the various species were not created in their current forms but have instead evolved through. natural undirected processes Darwin famously took many years to publish his ideas about how species form and. his theory of evolution through natural selection On the Origin of Species was published in 1858 only after. Darwin received a letter from Alfred Russel Wallace independently outlining the same ideas See the related. short film The Origin of Species The Making of a Theory. Fast forward to 1973 over 100 years after Darwin wrote his revolutionary ideas when Peter and Rosemary Grant. traveled to the Gal pagos Islands for the first time to study variability among finches within and among. populations By then the theory of evolution was no longer questioned by scientists but accepted as a central. unifying principle in biology However biologists were continuing to investigate and ask questions about the. processes that drive evolutionary change For example what roles do competition genetics and the environment. play How do these factors work together to produce the variety of species in existence today as well as those we. have discovered in the fossil record Forty years of research on the Gal pagos finches has helped provide some of. the answers,Islands Are Natural Laboratories, To gain insights on particular research questions researchers generally try to limit the number of variables being. considered For that reason studies in speciation often focus on groups of species that are closely related and. living in relatively contained isolated habitats such as islands. The Grants studies of speciation have focused on the finches living on the Gal pagos Islands These islands sit on. the equator in the Pacific Ocean 973 km west of Ecuador South America The distance between the mainland and. the closest island in the Gal pagos makes it unlikely for mainland species of plants or animals to colonize the. islands However given enough time some mainland species will make the journey Flying animals like birds bats. and insects can on rare occasions move from the mainland to ocean islands and from island to island even if. these are separated by large distances This can happen for example when birds are blown off course by a storm. Flying animals can accidentally carry seeds with them for example in mud on their feet which can germinate. The Origin of Species Revised March 2018,www BioInteractive org Page 3 of 12. Film Guide, The Origin of Species The Beak of the Finch Educator Materials.
and grow to form their own populations Large seeds like coconuts can float to the islands on their own and. germinate there, The Gal pagos Islands are not only remote but they are also geologically young They are volcanic islands that. began rising from the seafloor between 4 million and 5 million years ago Some of the first islands to emerge are. now back under water due to erosion and subsidence The current islands have been above the ocean surface for. about 3 million years or less Thus the species found on the Gal pagos Islands today are relatively few and most. have only existed there for less than 3 million years Scientists can study how these species evolved in a relatively. short period of time in a new environment that is largely undisturbed by human activities In addition on the. smaller islands like Daphne Major scientists can potentially study entire populations of animals living on those. islands for many generations For all these reasons islands can function like natural laboratories. Evolution of the Gal pagos Finches, When the Grants began their study they didn t know whether the Gal pagos finches arose from a single species. or from two or more that came to the islands independently At one extreme if each Gal pagos species came. separately from the mainland then each of the 13 Gal pagos species living on the islands today should be more. closely related to a species on the mainland than to another Gal pagos species. One way to study evolutionary relationships among species is to compare DNA sequences When the Grants. looked at genetic data from mainland birds and compared those to genetic data from the Gal pagos finches they. discovered that a single mainland species the grassquit is the closest living relative of all the finches This. discovery was not compatible with a multiple origins hypothesis The ancestral species to all of the finches on the. Gal pagos had likely been a seed eating species like the grassquit that arrived on the islands around 2 million. The first group of finches likely arrived on one of the Gal pagos Islands and over time diversified into different. species of birds The original founding population has gone extinct and probably other species have as well The. 13 species that inhabit the islands today are the result of 2 million years of evolution. When the first ancestral population of finches arrived on the islands many of the potential ecological niches were. still available because the islands were young and there was little if any competition for resources As different. populations of finches occupied these niches they evolved adaptations that enabled them to survive in the. different habitats Thus in a relatively short period of time many different species of finches evolved from a. single ancestral population a process called adaptive radiation. Finch phylogenetic tree,Comparisons of DNA,sequences revealed the. evolutionary relationships,among finch species The. data showed that all finch,species living in the,Gal pagos Islands today are.
more closely related to one,another than to any species. of birds on the mainland,suggesting that they,originated from a common. The Origin of Species Revised March 2018,www BioInteractive org Page 4 of 12. Film Guide, The Origin of Species The Beak of the Finch Educator Materials. Today 13 species of finches live on the islands of the Gal pagos archipelago and an additional one on Cocos. Island an uninhabited island off the coast of Costa Rica located about 720 km north of the Gal pagos Islands This. rapid radiation of finch species would not have occurred in an environment in which all the ecological niches were. already occupied, As illustrated by the phylogenetic tree in the figure above when the founding population diverged into two.
descendants one of the descendants evolved into the warbler finch and the other descendant gave rise to all the. other finch species The warbler finch is the only insect eating Gal pagos finch that can catch insects while in. flight Thousands of years later the finch population diverged and one descendent led to the vegetarian finch and. the other to the ancestor of the remaining finch species The vegetarian finch is aptly named because its diet is. mainly made up of fruits flower buds and blossoms The final two groups that later formed branches of their. own on the Gal pagos finch family tree are the insect eating tree finches and the seed eating ground finches. which also include the cactus finches, One trait which is highly diverse among the Gal pagos finch species is the size and shape of the beak For. example the cactus finch Geospiza scandens has a long pointed beak capable of probing and opening cactus. fruits to eat the seeds It also eats the pollen and nectar of the cactus flowers With its shorter blunter beak the. medium ground finch Geospiza fortis can only eat cactus seeds once fruits fall to the ground or are opened by. cactus finches However it can also crack open some larger and sturdier species of seeds that the cactus finch. cannot open,Table 1 The Gal pagos Finches,Scientific Name English Name Approximate weight. Geospiza fuliginosa Small ground finch 14,Geospiza fortis Medium ground finch 20. Geospiza magnirostris Large ground finch 34,Geospiza difficilis Sharp beaked ground finch 20. Geospiza scandens Cactus finch 21,Geospiza conirostris Large cactus finch 28.
Camarhynchus parvulus Small tree finch 13,Camarhynchus pauper Medium tree finch 16. Camarhynchus psittacula Large tree finch 18,Camarhynchus pallidus Woodpecker finch 20. Camarhynchus heliobates Mangrove finch 18,Platyspiza crassirostris Vegetarian finch 35. Certhidea olivacea Warbler finch 8,Adaptation and Speciation. Most of the Grants research has focused on the medium ground finch and the cactus finch both on the island of. Daphne Major By observing these birds year after year for four decades they have shown that as the. environment changes so too do the traits of the birds. The film shows that when the island of Daphne Major experienced an extreme drought in 1977 food quickly. became scarce Medium ground finches have stout beaks that are ideal for picking up seeds from the ground but. beak sizes vary greatly within medium ground finch populations When seeds were plentiful there were many. different seed sizes and all the medium ground finches had enough to eat But after the drought the smaller soft. The Origin of Species Revised March 2018 www BioInteractive org Page 1 of 12 The Origin of Species The Beak of the Finch Film Guide Educator Materials OVERVIEW The Beak of the Finch is one of three films in HHMI s Origin of Species collection Naturalists from Charles Darwin to E O Wilson have marveled at the incredible number and diversity of species on Earth Understanding why there are

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