ESCRITA CIENTÍFICA

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Tipos climáticos - atendendo pedidos!

Por: Prof. Marcus Cabral

Fatores como latitude, altitude, maritimidade, continentalidade, pressão atmosférica e influência das correntes marítimas também ajudam a definir os dez tipos principais de climas do mundo. Veja a seguir as peculiaridades de cada um:

Polares: é o clima com as menores temperaturas do planeta: no inverno, ela permanece em torno de -30ºC e, no verão, a média é de 4ºC. está presente no extremo norte do Canadá, da Rússia e do Alasca, em parte da península Escandinava e na Antártica. A umidade relativa do ar é alta entre 70% e 80%, mas a precipitação, bastante reduzida: cerca de 100 milímetros de neve acumulados ao ano.

Temperados: Apresentam as quatro estações bem definidas. Há diferenças entre os locais próximos e os que estão longe do mar. E se dividem, basicamente, em:
 - Temperado Mediterrâneo: É o clima predominante no sul da Europa, golfo do México e sudeste da China, entre outras regiões. Os verões são quentes e secos – a temperatura chega a 30ºC – e os invernos, moderados e com um pouco de chuva. As mínimas de temperatura podem atingir 0ºC.
- Temperado Continental: Também de latitudes médias, o temperado continental está presente nas áreas interiores da América do Norte, da Europa e do leste da Ásia. O inverno é muito rigoroso e o verão quente - as médias de temperatura são -5ºC e 24ºC, respectivamente. As chuvas são escassas, sobretudo no inverno. É interessante notar que, apesar de estarem ambos nas mesmas latitudes, os climas temperados oceânico e continental são muito diferentes, por causa da distância em relação ao mar. No temperado continental, é a continentalidade que justifica a umidade relativa do ar mais baixa e a grande amplitude térmica anual.
- Temperado Oceânico: Presente nas regiões de litoral das latitudes médias, como o oeste e noroeste da Europa. As chuvas são abundantes durante o ano e as temperaturas não sofrem muita variação - os invernos são frios (média de -3ºC) e os verões, frescos (média de 15ºC). A proximidade com o mar (maritimidade) é um fator de influência nesse clima: a água, que demora mais para se aquecer e, depois, para se esfriar, mantém a amplitude térmica baixa no continente. As chuvas bem distribuídas no decorrer do ano também se devem à umidade da região litorânea, que recebe as massas de ar do oceano.

Tropical: Fica nas áreas entre os trópicos de Câncer e de Capricórnio, cobrindo grande parte do território brasileiro e do continente africano, Índia, península da Indochina e norte da Austrália. O clima é quente, com média anual superior a 20ºC. As chuvas são intensas no verão e, no estante do ano, ocorrem mais nas regiões próximas ao mar. No Sudeste Asiático, destacam-se as chuvas de monções, tempestades torrenciais provocadas pelo vento úmido que sopra do oceano. Quando começa o verão, o continente se esquenta rapidamente, formando uma zona de baixa pressão, e as massas de ar do oceano trazem as chuvas; essa dinâmica, comum em outros pontos do planeta, tem maiores proporções nessa região em virtude da vastidão da terra (o continente asiático) e de mar (os oceanos Índico e Pacífico) envolvida no fenômeno.

Equatorial: Quente e úmido durante o ano todo, está presente na região da linha do Equador e nas áreas de baixa latitude, como a América Central, a Indonésia, a região central da África e o norte do Brasil. A umidade relativa do ar é elevada, com média anual de 90%, e a chuva é abundante durante o ano todo. A temperatura também é alta e estável, com média anual de 25ºC ;

Subtropical: É o clima das regiões ao sul do trópico de Capricórnio: sul de São Paulo, Paraná, Santa Catarina e Rio Grande do Sul. A quantidade de chuva não varia muito durante o ano, mas as temperaturas mudam bastante: o inverno é frio e o verão, quente.

Tropical Árido:  Ocorre em regiões como o Saara, o centro da Austrália, norte do México e sul dos EUA. O índice pluviométrico é baixíssimo: a média anual de precipitação é inferior a 250 milímetros, o equivalente a cerca de um mês de chuva no clima equatorial. A umidade relativa do ar também é muito baixa, cerca de 40%. A amplitude térmica diária é elevada: de dia a temperatura ultrapassa os 40ºC e, à noite, chega a graus negativos.

Continental árido: Clima seco, presente nas regiões temperadas: Ásia Central (Cazaquistão, no interior da China e Mongólia), Patagônia e planalto oeste das Montanhas Rochosas (EUA). A precipitação é tão escassa quanto a do clima tropical árido, abaixo dos 250 milímetros por ano, mas, diferentemente deste, a temperatura apresenta grande variação no decorrer do ano: no verão, a média é de 17ºC e, no inverno, de -20ºC.

Montanhoso: Ocorre nas cadeias de montanhas ao redor do globo: áreas elevadas dos Andes, Montanhas Rochosas, Alpes e Himalaia. É um clima frio, com temperatura que diminui 6ºC a cada mil metros de altitude. Acima dos 2 mil metros há neve constante. A umidade relativa do ar varia conforme o lado da cadeia: a média é de 90 do lado do vento (barlavento), caindo para até 30 do lado contrário (sotavento). A quantidade de precipitação também é variável, chegando a 2 mil milímetros por ano nas regiões tropicais.

Câmara aprova lei que leva à prisão quem maltratar animais

Por Redação Yahoo! Brasil | Yahoo Notícias – qua, 29 de abr de 2015

 

 

 

Uma lei esperada há tempos finalmente saiu do papel e foi aprovada pela Câmara dos Deputados: a partir de agora, maltratar animais leva para a prisão.

A detenção de três anos para quem matar animais é apenas uma parte do projeto, que também legaliza a eutanásia em caso de doenças — desde que o remédio letal seja aplicado de forma “assistida e controlada”.

Além da prisão para quem provocar a morte de cães e gatos, outro aspecto que foi ressaltado é dos maus tratos, que agora pode levar o agressor a detenção de três meses a um ano.

Ainda dentro da proposta aprovada, promover luta entre cães, a popular rinha, também rende cadeia, também tem punição, de três a cinco anos na cadeia.

Com as punições previstas, a expectativa é que os maus tratos aos animais sofram diminuição drástica. Qualquer denúncia será investigada como crime e punida conforme a nova lei determina.

 

Dinosaurs Fell Victim to “Perfect Storm” of Events, Study Infers

by AMNH on 07/28/2014 09:00 am

Research posts

 

Dinosaurs might have survived the asteroid strike that wiped them out if it had taken place slightly earlier or later in time, according to new research conducted in part by the American Museum of Natural History. The study, published today in Biological Reviews, builds a new narrative of the prehistoric creatures’ demise some 66 million years ago when a six-mile- (10-kilometer-) wide asteroid struck what is now Mexico.

Triceratops, an herbivore common in the Maastrichtian stage.

“The dinosaurs were victims of colossal bad luck,” said lead author Steve Brusatte, a researcher at the University of Edinburgh’s School of GeoSciences. “Not only did a giant asteroid strike, but it happened at the worst possible time, when their ecosystems were vulnerable. Our new findings help clarify one of the enduring mysteries of science.”

The international team of scientists, which included the Museum’s Paleontology Division Chair Mark Norell, who was Brusatte’s Ph.D. advisor, studied an updated catalog of dinosaur fossils to create a picture of how dinosaurs changed over the few million years before the asteroid hit. They found that Earth was experiencing environmental upheaval, including extensive volcanic activity, changing sea levels, and varying temperatures.
At this time, the dinosaurs’ food chain was weakened by a lack of diversity among the large plant-eating dinosaurs on which others preyed, probably because of changes in the climate and environment, the researchers suggest.

The dinosaur-dominated fauna witnessed the asteroid impact at the end of the Cretaceous period about 66 million years ago and was replaced in the earliest Paleocene by a mammal-dominated fauna. This illustration shows representative members of major Campanian, Maastrichtian, and earliest Paleocene (Puercan) North American terrestrial vertebrates.
Image credit:Thomas Williamson, New Mexico Museum of Natural History and Science

This created a “perfect storm” in which dinosaurs were vulnerable and unlikely to survive the aftermath of the asteroid strike. That asteroid impact would have caused tsunamis, earthquakes, wildfires, sudden temperature changes, and other environmental changes. As food chains collapsed, the dinosaurs were wiped out, one species after another. The only dinosaurs to survive were those that could fly, from which modern birds descended.

The researchers suggest that if the asteroid had struck a few million years earlier, when the range of dinosaur species was more diverse and food chains were more robust, or later, when new species had time to diversify, then they very likely would have survived.
Ongoing studies in Spain and China could result in an even better understanding of what occurred during this time frame, more than 66 million years ago.

Developmental Timing Offers Another Window Into Dinosaur-Bird Transition

by AMNH on 05/30/2012 12:00 am

Research posts

Photographs of the skull of a baby Coelophysis (left), a small dinosaur from the late Triassic, and the skull of Archaeopteryx (right), thought to be one of the earliest birds. © Harvard/B.-A. Bhullar.

A new study has used skull anatomy to show that the evolution of birds from dinosaurs may have resulted from a drastic change in dinosaur development.

In a study published this week in the journal Nature, researchers from Harvard University, the Museum, the New York Institute of Technology, The University of Texas at Austin, and the Autonomous University of Madrid report evidence that while many dinosaurs took years to reach sexual maturity, birds sped up the developmental clock, which led them to retain the physical characteristics of baby dinosaurs.
The paper adds another dimension to a long history of research on the theropod origin of birds. “By analyzing fossil evidence from skeletons, eggs, and soft tissue of bird-like dinosaurs and primitive birds, we’ve learned that birds are living theropod dinosaurs, a group of carnivorous animals that include Velociraptor,” says Mark Norell, chair of the Museum’s Division of Paleontology and one of the paper’s co-authors. “This new work advances our knowledge by providing a powerful example of how developmental changes played a major role in the origin and evolution of birds.”
Although dinosaurs had mouths bristling with teeth and birds have proportionally larger eyes and brains, the skulls of modern birds and juvenile dinosaurs demonstrate a surprising degree of similarity, a realization that sparked this study.

Researchers used CT scanners to image dozens of skulls of species ranging from modern birds to theropods to early dinosaus. By noting various “landmarks”—such as the orbits, cranial cavity, and other bones in the skull—on each scan, scientists were able to track the changes in skull shape over millions of years.
The study revealed that while non-avian dinosaurs (even those closely related to modern birds) undergo vast morphological changes as they mature, the skulls of juvenile and adult birds remain remarkably similar. This “paedomorphosis,” in which the adults of a species look like the juveniles of their ancestors, was an important factor in the evolution of birds from dinosaurs.

Modern bird skulls resemble those of young dinosaurs due to a process known as progenesis, which causes an animal to reach sexual maturity earlier. Unlike their dinosaurian ancestors, modern birds take dramatically less time—just 12 weeks in some species—to develop to maturity, leading birds to retain the characteristics of their juvenile ancestors into adulthood.
For more information on this study, see this press release.

MEGA SERPENTE

Stay far away from this enormous Fossil Friday!

Pictured are the ribs and vertebrae of Madtsoia bai, or “Cow Valley [snake]” which lived about 55 million years ago, during the Early Eocene. Some extinct snakes grew to remarkable size. This is a section from the trunk of Madtsoia, a snake whose body would have reached over 30 feet (9.2 meters) in length! In some extinct snakes, small spurs near the tail are ancient remnants of the hind limbs found in snake ancestors.
This fossil is located in the Museum’s Hall of Vertebrate Origins.

Building Better Skull Models For Ancient Carnivores

by AMNH on 04/29/2015 05:27 pm

Research posts

Analyzing the skulls of living species showed unexpected similarities.
© AMNH/Z.-J. Tseng

When paleontologists put together a life history for a long-extinct animal, they try to understand its diet by looking at modern animals with similar skull shapes and tooth patterns. But this practice is far from foolproof. New modeling and tests based on living species conducted by scientists at the American Museum of Natural History show that the link between animal diets and skull biomechanics is complex, with a stronger influence from ancestry than previously thought.

“Traditionally, when we looked at a fossilized skull with pointy piercing teeth and sharp slicing blades, we assumed that it was primarily a meat eater, but that simplistic line of thinking doesn’t always hold true,” said John J. Flynn, the Museum’s Frick Curator of Fossil Mammals and a co-author on the new work published today in the journal PLOS ONE. “We’ve found that diet can be linked to a number of factors—skull size, biomechanical attributes, and often, most importantly, the species’ position in the tree of life.”

 Dr. Flynn and Z. Jack Tseng, a National Science Foundation and Frick Postdoctoral Fellow in the Museum’s Division of Paleontology, looked at the relationship between skull shape and function of five different modern carnivore species: “hypercarnivores” like wolves and leopards whose diet is more than 70 percent meat and more omnivorous “generalists” such as mongooses, skunks, and raccoons. The initial modeling, which mapped bite force against the stiffness of the animal’s skull, yielded a surprise.
“Animals with the same diets and biomechanical demands, like wolves and leopards—both hypercarnivores—were not linking together,” Dr. Tseng said. “Instead, we saw a strong signal driven mostly by ancestry, where, for example, the leopard and the mongoose bind together because they’re more closely related in an evolutionary context, although they have very different dietary preferences and feeding strategies.”

Improving our understanding of skull structure could help researchers learn more about the habits of extinct animals.
© AMNH/Z.-J. Tseng

But once Tseng and Flynn accounted for the strong effects of ancestry and skull size on the models, hypercarnivores and generalists still could be distinguished based on biomechanics, in particular by looking at where along the tooth row the skull is strongest. The skulls of heavy meat eaters tend to be stiff near the front teeth for hunting, and the back teeth for crushing bones and slicing meat. In contrast, generalist skulls get slightly stiffer from the front row of teeth to the back row.

With an improved shape-function computer model in hand, Flynn and Tseng applied the research to a pair of extinct species: Thinocyon velox, a predatory mammal that was part of the now-extinct Creodont group, and Oodectes herpestoides, an early fossil predecessor of modern carnivores. The results suggested that T. velox likely had a unique hypercarnivorous feeding style that emphasized prey capture with its front teeth and powerful slicing and crushing with its back teeth, while O. herpestoides was a generalist.
“Beyond feeding adaptations of extinct species, we also want to decipher how adaptations evolved using reconstructed ancestors of living and fossil forms,” Tseng said. “We are applying similar types of skull shape and biomechanical analyses to reconstructed hypothetical ancestor skulls of Carnivora and their relatives to map out and better understand the long history of feeding adaptation of living top predators.”

Tags: Fossils, Mammals, Paleontology