Plants Evolved to Survive Cold Weather

Have you ever wondered why some trees lose their leaves in the winter? It’s actually how these trees cope with the cold weather. But what about other plants that seem to disappear during the chilly winter months? Scientists have learned that plants have evolved in different ways to deal with frosty temperatures.

Photo by Jason Hollinger

Fossil evidence and records of past climate conditions tip-off that early flowering plants grew in warm tropical regions. As plants continued to grow and spread to different areas, they eventually reached higher elevations where temperatures were cooler. With the cold came challenges for survival so plants evolved in ways to combat the wintry weather.

Plants can’t move to escape the cold and they can’t make heat like humans do to keep warm. But it’s not really the cold that’s the biggest threat to plants—it’s the ice. Freezing and thawing can create air bubbles that can block their internal water flow. So plants that live in colder climates need to protect themselves from the ice.

Photo by muffinn

Here are some ways that plants have evolved to cope with the cold:

Oak trees evolved to avoid freezing by shutting off its water flow from the roots to its leaves. This is why oak trees lose their leaves during the winter chill. When the warmer weather returns, the flow of water is turned back on and new leaves grow.

Birch trees grow with narrow water transport system which is less prone to blockage during freezing temperatures.

Other plants have the ability to die and come back when the weather becomes warmer. They re-sprout from their roots or grow as new plants from seeds when the weather is right.

Newly Discovered Fossils related to the Movement of Early Humans

Researchers have recently found that Australopithecus ancestors may have used different ways of mobilization to walk around on two feet. This particular research is one of six studies to have been published last week in science that portrays the gathering of more than four years of research into the anatomy of Australopithecus sediba.

Discovered in the Malapa cave in South Africa, the two million year-old fossils are considered to be some of the most complete early human ancestral remains to have ever been discovered. This most recent study was published by Boston University assistant Professor of Anthropology, Jeremy DeSilva and Assistant Professor of Physical Therapy, Kenneth Holt. With their findings, DeSilva and Holt first hypothesized that this particular species walked like a human with a fully extended leg. They also believed that this species had an ape-like walk with an inverted foot, which produced hyperpronation of the foot and excessive rotation of the knee and hip during bipedal walking. As a result, these findings indicated to the rest of the science world that there could have possibly been different types of bipedalism throughout the human evolution.

According to Professor Jeremy DeSilva:

“As others have suggested, there were different kinematic solutions for being a bipedal hominine in the Plio-Pleistocene (The recent discovery of an Ardipithecus-like foot from 3.4 million-year-old deposits at Burtele). The mode of locomotion suggested by the Malapa skeletons indicates a compromise between an animal that is adapted for extended knee bipedalism and one that either still had an arboreal component or had re-evolved a more arboreal lifestyle from a more terrestrial ancestor.”

According to several other published works, the Australopithecus sediba were known to have a combination of unique features in the hand, upper limb, thorax, spine and foot. The foot, in particular, possessed an anatomical mosaic, which further supports the theory today that there were multiple forms of bipedal locomotion in the Plio-Pleistocene.

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