Top 10 Things That Make Humans Special

Humans are unusual animals by any stretch of the imagination. Our special abilities, from big brains to opposable thumbs, have allowed us change our world dramatically and even leave the planet. There are also odd things about us that are, well, just special in relation to the rest of the animal kingdom. So what exactly makes us so special? Some things we take completely for granted might surprise you.

1. Speech

The larynx, or voice box, sits lower in the throat in humans than in chimps, one of several features that enable human speech. Human ancestors evolved a descended larynx roughly 350,000 years ago. We also possess a descended hyoid bone — this horseshoe-shaped bone below the tongue, unique in that it is not attached to any other bones in the body, allows us to articulate words when speaking.

2  Upright Posture

Humans are unique among the primates in how walking fully upright is our chief mode of locomotion. This frees our hands up for using tools. Unfortunately, the changes made in our pelvis for moving on two legs, in combination with babies with large brains, makes human childbirth unusually dangerous compared with the rest of the animal kingdom. A century ago, childbirth was a leading cause of death for women. The lumbar curve in the lower back, which helps us maintain our balance as we stand and walk, also leaves us vulnerable to lower back pain and strain.

3.      Nakedness

We look naked compared to our hairier ape cousins. Surprisingly, however, a square inch of human skin on average possesses as much hair-producing follicles as other primates, or more — humans often just have thinner, shorter, lighter hairs. Fun fact about hair: Even though we don't seem to have much, it apparently helps us detect parasites, according to one study.

4.      Clothing

Humans may be called "naked apes," but most of us wear clothing, a fact that makes us unique in the animal kingdom, save for the clothing we make for other animals. The development of clothing has even influenced the evolution of other species — the body louse, unlike all other kinds, clings to clothing, not hair.

5.      Extraordinary Brains

Without a doubt, the human trait that sets us apart the most from the animal kingdom is our extraordinary brain. Humans don't have the largest brains in the world — those belong to sperm whales. We don't even have the largest brains relative to body size — many birds have brains that make up more than 8 percent of their body weight, compared to only 2.5 percent for humans. Yet the human brain, weighing only about 3 pounds when fully grown, give us the ability to reason and think on our feet beyond the capabilities of the rest of the animal kingdom, and provided the works of Mozart, Einstein and many other geniuses.

6.      Hands

Contrary to popular misconceptions, humans are not the only animals to possess opposable thumbs — most primates do. (Unlike the rest of the great apes, we don't have opposable big toes on our feet.) What makes humans unique is how we can bring our thumbs all the way across the hand to our ring and little fingers. We can also flex the ring and little fingers toward the base of our thumb. This gives humans a powerful grip and exceptional dexterity to hold and manipulate tools with.

7.      Fire

The human ability to control fire would have brought a semblance of day to night, helping our ancestors to see in an otherwise dark world and keep nocturnal predators at bay. The warmth of the flames also helped people stay warm in cold weather, enabling us to live in cooler areas. And of course it gave us cooking, which some researchers suggest influenced human evolution — cooked foods are easier to chew and digest, perhaps contributing to human reductions in tooth and gut size.

8.      Blushing

Humans are the only species known to blush, a behavior Darwin called "the most peculiar and the most human of all expressions." It remains uncertain why people blush, involuntarily revealing our innermost emotions. The most common idea is that blushing helps keep people honest, benefiting the group as a whole.

9.      Long Childhoods

Humans must remain in the care of their parents for much longer than other living primates. The question then becomes why, when it might make more evolutionary sense to grow as fast as possible to have more offspring. The explanation may be our large brains, which presumably require a long time to grow and learn.

10.  Life after Children

Most animals reproduce until they die, but in humans, females can survive long after ceasing reproduction. This might be due to the social bonds seen in humans — in extended families, grandparents can help ensure the success of their families long after they themselves can have children.

What is evolution?

In biology, evolution is the change in the characteristics of a species over several generations and relies on the process of natural selection.

According to Hall & Hallgrímsson “Evolution is change in the heritable characteristics of biological populations over successive generations.”

• The theory of evolution is based on the idea that all species are related and gradually change over time.
  
• Evolution relies on there being genetic variation in a population which affects the physical characteristics (phenotype) of an organism.
• Some of these characteristics may give the individual an advantage over other individuals which they can then pass on to their offspring. 

What is natural selection?

• Charles Darwin’s theory of evolution states that evolution happens by natural selection.
• Individuals in a species show variation in physical characteristics. This variation is because of differences in their genes.
• Individuals with characteristics best suited to their environment are more likely to survive, finding food, avoiding predators and resisting disease. These individuals are more likely to reproduce and pass their genes on to their children.
• Individuals that are poorly adapted to their environment are less likely to survive and reproduce. Therefore their genes are less likely to be passed on to the next generation.
• As a consequence those individuals most suited to their environment survive and, given enough time, the species will gradually evolve.

Natural selection in action: the Peppered moth

• Before the industrial revolution in the mid-1700s, the peppered moth was most commonly a pale whitish color with black spots.
• This coloring enabled them to hide from potential predators on trees with pale-coloured bark, such as birch trees.
• The rarer dark-coloured peppered moths were easily seen against the pale bark of trees and therefore more easily seen by predators.
• As the Industrial Revolution reached its peak, the air in industrial areas became full of soot. This stained trees and buildings black.
• As a result, the lighter moths became much easier to spot than the darker ones, making them vulnerable to being eaten by birds.
• The darker moths were now camouflaged against the soot-stained trees and therefore less likely to be eaten.
• Over time this change in the environment led to the darker moths becoming more common and the pale moths rarer.

What have genes got to do with it?

• The mechanisms of evolution operate at the genomic level. Changes in DNA^? Sequences affect the composition and expression^? of our genes, the basic units of inheritance^?.
• To understand how different species have evolved we have to look at the DNA sequences in their genomes.
• Our evolutionary history is written into our genome. The human genome looks the way it does because of all the genetic changes that affected our ancestors.
• When DNA and genes in different species look very similar, this is usually taken as evidence of them sharing ancestors.
• For example, humans and the fruit fly, Drosophila melanogaster, share much of their DNA. 75 per cent of genes that cause diseases in humans are also found in the fruit fly.
• DNA accumulates changes over time. Some of these changes can be beneficial, and provide a selective advantage for an organism.
• Other changes may be harmful if they affect an important, everyday function. As a result some genes do not change much. They are said to be conserved.

Different types of evolution

Convergent evolution

• When the same adaptations evolve independently, under similar selection pressures.
• For example, flying insects, birds and bats have all evolved the ability to fly, but independently of each other.

Co-evolution

• When two species or groups of species have evolved alongside each other where one adapts to changes in the other.
• For example, flowering plants and pollinating insects such as bees.

Adaptive radiation

• When a species splits into a number of new forms when a change in the environment makes new resources available or creates new environmental challenges.

For example, finches on the Galapagos Islands have developed different shaped beaks to take advantage of the different kinds of food available on different islands.

What is a virus?

Ans 1:

A virus is a microscopic organism that can replicate only inside the cells of a host organism. Most viruses are so tiny they are only observable with at least a conventional optical microscope. Viruses infect all types of organisms, including animals and plants, as well as bacteria and archaea. Approximately 5000 different viruses have been described in detail at the current time, although it is known that there are millions of distinct types.  Viruses are found in virtually every ecosystem on Earth, and these minute life forms are thought to be the most abundant type of biological entity.  The study of viruses is known as virology, a specialty within the field of  microbiology.

Ans 2:

An infective agent that typically consists of a nucleic acid molecule in a protein coat, is too small to be seen by light microscopy, and is able to multiply only within the living cells of a host.

Ans 3:

A piece of code which is capable of copying itself and typically has a detrimental effect, such as corrupting the system or destroying data.

Ans 4:

Viruses are tiny organisms that may lead to mild to severe illnesses in humans, animals and plants. This may include flu or a cold to something more life threatening like HIV/AIDS.

What is respiratory system?

Ans 1:

The human respiratory system is a series of organs responsible for taking in oxygen and expelling carbon dioxide. The primary organs of the respiratory system are lungs, which carry out this exchange of gases as we breathe.

Ans 2:

The respiratory system (called also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for the process of respiration in an organism.