Hibernation helps animals survive the changing seasons. Foods that bears eat, such as berries and flowers, are much less available during cold winter months. When they hibernate, bears enter a deep sleep. ... While they sleep, the bears can survive because their bodies live off of their stored fat or food.
During hibernation, the animal’s body temperature, heart rate and breathing rate all drop to significantly lower levels. Animals do this to survive the winter because the weather is cold and food is scarce. It is advantageous because these animals can quite literally shut themselves off for weeks at a time rather than try and survive through harsh weather conditions.
While many people think bears are hibernators, they actually participate in a similar, though not exact, practice. Instead of hibernating, bears fall into a deep sleep called torpor. During torpor, heart rate and breathing rate decreases, body temperature reduces slightly and bears do not eat or release bodily waste. Bears can sleep more than 100 days without eating, drinking, or passing waste!
Bears sleep in dens that they make themselves, as well as in hollow trees, caves and dens built by other bears. A den can be built in 3–7 days, however, the timing of den building varies from bear to bear. While some bears build their dens months before hibernation season, others choose to excavate their dens.
These animals can dramatically drop their body temperature to below freezing—salty body fluids work to prevent tissue crystallization in particularly cold temperatures.
So really, animals that are true hibernators don’t actually sleep through the entire winter.
The urea produced by their fat metabolism is broken down and the nitrogen is re-used by the bear to rebuild protein.
Answer:
Nuestro planeta esta habitada por numerosas <em>especies</em>, muchas de ellas extendidas en grandes y diversas zonas. Sin embargo, existen especies que habitan una sola <em>área/región</em> con características<em> ambientales</em> únicas para su desarrollo.
Explanation:
Entre las miles de especies que habitan el planeta, muchas de ellas pueden estar ampliamente distribuidas, mostrando adaptaciones a una gran variedad de ambientes y hábitats, mientras que muchas otras solo se encuentran restringidas a determinadas areas o regiones particulares que presentan condiciones ambientales determinadas. Esta diferencia en distribución esta muy relacionada a la historia de la especie, a la edad de la misma sobre la tierra, adaptaciones a los ambientes y capacidades reproductivas y de dispersión.
Dentro de la clasificación de especies de acuerdo a su distribución, podemos mencionar a las especies
- nativas: aquellas que habitan y se distribuyen las áreas naturales donde se originaron,
- endemicas: entran dentro del concepto de nativas, pero a parte se caracterizan por habitar <u><em>unicamente</em></u><em> una región en particular debido a las condiciones ambientales</em> que les son propicias para su desarrollo. Estas especies no pueden trasladarse a otras regiones.
- exoticas: aquellas especies que salen de su area natural de distribución para habitar otras areas mas lejanas. Allí pueden establecerse e interactuar con especies nativas sin causar grandes daños.
- invasoras: especies exoticas que llegan a otras areas, que se establecen y que tienen la capacidad de reproducirse a una tasa superior a la de las especies nativas, invadiendolas y desplazandolas. Interactuan con las especies nativas y causan daños importantes.
Los términos nativos, endemicos, exóticos son <em>relativos al área a la que se esté haciendo alusión</em>: un continente, un país, una región o un bioma.
The correct answer to this question is letter A. Speciation. <span>The Galapagos finch species are an excellent example of speciation. It was Charles Darwin himself who is responsible and made the start of the study in Genetics through his natural selection and survival of the fittest. Hope this helps answer your question.</span>
Answer:
Joint - a joint is where two bones articulate
In this case, the femur and tibia form a joint.
