https://padlet.com/cgdaniel811/eqxye7x6bbes Cengage Biology 17.13 en-us 2018-04-22 19:08:59 UTC 2024-09-30 02:14:06 UTC hello@padlet.com https://padlet-uploads.storage.googleapis.com/269633375/b51d181997e6142372d49a26bb6cece1/puppers_.jpg cgdaniel811 https://padlet.com/cgdaniel811/eqxye7x6bbes/wish/254171847

Researchers study evolution of viruses and other infectious agents by grouping them into clades based on biochemical characters

Viruses are not alive, but can mutate every time they infect host, so genetic material changes over time

H5N1 strain of influenza (flu) virus, which infects birds and other animals

Has very high mortality rate in humans, but human-to-human transmission is rare

Replicates in pigs without causing symptoms

Transmit virus to other pigs and humans

Phylogenetic analysis of H5N1 isolated from pigs showed virus “jumped” from birds to pigs at least three times since 2005, and one of isolates had acquired potential to be transmitted among humans

Increased understanding of how virus adapts to new hosts is helping researchers design more effective vaccines for it

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Story of the Hawaiian honeycreepers offers example of how finding ancestral connections can help species that are still living

First Polynesians arrived on Hawaiian Islands before 1000 a.d., and Europeans followed in 1778

Rich ecosystem was hospitable to these newcomers and their domestic animals and crops

Escaped livestock began to eat and trample rain forest plants that had provided honeycreepers with food and shelter

Entire forests were cleared to grow imported crops, and plants that escaped cultivation began to crowd out native plants

Mosquitoes accidentally introduced in 1826 spread diseases such as avian malaria from imported chickens to native bird species

Stowaway rats and snakes ate their way through populations of native birds and their eggs

Mongooses deliberately imported to eat the rats and snakes preferred to eat birds and bird eggs

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Isolation that had spurred adaptive radiations also made honeycreepers vulnerable to extinction

Divergence from the ancestral species led to loss of unnecessary traits such as defenses against mainland predators and diseases

 Specializations such as extravagantly elongated beaks became hindrances when birds’ habitats suddenly changed or disappeared

43+ honeycreeper species that had thrived on islands before humans arrived were extinct by 1778

Conservation efforts began in 1960s, but 26 more species have since disappeared

Today, 35 of remaining 68 species are endangered

Still pressured by established populations of invasive, nonnative species of plants and animals

Rising global temperatures are also allowing mosquitoes to invade high-altitude habitats that had previously been too cold for the insects, so honeycreeper species remaining in these habitats are now succumbing to avian malaria and other mosquito-borne diseases

]]> 2018-04-22 19:15:24 UTC https://padlet.com/cgdaniel811/eqxye7x6bbes/wish/254172306 cgdaniel811 https://padlet.com/cgdaniel811/eqxye7x6bbes/wish/254251076 Among other applications, phylogeny research can help us understand the spread of infectious diseases, and also to focus our conservation efforts.]]> 2018-04-23 06:08:45 UTC https://padlet.com/cgdaniel811/eqxye7x6bbes/wish/254251076 cgdaniel811 https://padlet.com/cgdaniel811/eqxye7x6bbes/wish/254252220 2018-04-23 06:16:11 UTC https://padlet.com/cgdaniel811/eqxye7x6bbes/wish/254252220