Ranked: The Life Expectancy of Humans and 49 Other Animals
Connect with us

Science

Ranked: The Life Expectancy of Humans and 49 Other Animals

Published

on

life expectancy of humans compared to animals

Ranked: The Life Expectancy of Humans and 49 Other Animals

For most of history, average life expectancy at birth for humans has stood around 30 years. But thanks to recent breakthroughs in technology and modern medicine, humans are now born with an average life expectancy closer to 80 years.

Some might argue this is one of mankind’s greatest achievements. With this rise in life expectancy, how do human lifespans now rank compared to other animals?

This graphic from Alan’s Factory Outlet covers the life expectancy of 50 different animals ranging from amphibians to arthropods, and even includes one species that’s immortal (well, in theory).

Let’s take a closer look at lifespans in the animal kingdom.

The Longest Living Things

Here are some of the longest living animals, where even with advancements in modern medicine, humans are likely far off from matching.

The Deep-Sea Tube Worm

The deep-sea tube worm, also known as Riftia pachyptila, lives until about 250 years old, though in some cases this can stretch much further.

Amazingly, they have no digestive system, mouth, or anus, and thus do not consume food to survive in a traditional sense. Instead, the bacteria living inside their bodies helps to transform the sulfur from nearby hydrothermal vents into energy.

This makes the deep-sea tube worm one of the few animals on Earth that does not derive its nutrients (either directly or indirectly) from sunlight.

The Immortal Jellyfish

The immortal jellyfish, otherwise known as Turritopsis dohrnii, is biologically immortal.

How is this possible?

Essentially, these creatures revert and transition backwards from sexual maturity towards sexual immaturity in a process called transdifferentiation—where adult cells are converted into other types of tissue. Not surprisingly, processes like these are getting plenty of human attention in gene therapy and scientific research.

Giant Barrel Sponge

The giant barrel sponge can live for 2,300 years. These cool creatures live on the reef surface of the ocean, and are bowl shaped, which provides habitat for many other invertebrates including crabs, shrimps, as well as fish. In addition, sponges have no tissue and each of their individual cells can do the same job of any other cell.

Some experiments have even shown sponges reform and have their cells swim back together when blended up in a blender. If they didn’t, that would be a very cruel experiment.

Human Lifespans: A Rising Trend To Watch

The number of centenarians—those 100 or more years old—stands at 570,000 today.

Here are the countries where they are most common compared to their respective populations.

Country/Region% Of Population
Japan0.062%
Uruguay0.061%
Hong Kong0.047%
Puerto Rico0.045%
France0.030%
Spain0.028%
Italy0.028%
Cuba0.027%

While figures in the one-hundredth of a percent range may sound underwhelming, this is still a 1,500% jump from the 33,000 centenarians that lived in the 1950s.

Slowly but surely, as human life expectancy continues to grow, our species seems destined to climb up the age ladder—and who knows, we may even be able to eventually live beyond some of the other creatures on this list.

Click for Comments

Misc

Visualizing the Evolution of Vision and the Eye

The eye is one of the most complex organs in biology. We illustrate its evolution from a simple photoreceptor cell to a complex structure.

Published

on

Roadmapping the Evolution of the Eye

Throughout history, numerous creatures have evolved increasingly complex eyes in response to different selective pressures.

Not all organisms, however, experience the same pressures. It’s why some creatures today still have eyes that are quite simple, or why some have no eyes at all. These organisms exemplify eyes that are “frozen” in time. They provide snapshots of the past, or “checkpoints” of how the eye has transformed throughout its evolutionary journey.

Scientists study the genes, anatomy, and vision of these creatures to figure out a roadmap of how the eye came to be. And so, we put together an evolutionary graphic timeline of the eye’s different stages using several candidate species.

Let’s take a look at how the eye has formed throughout time.

Where Vision Comes From

The retina is a layer of nerve tissue, often at the back of the eye, that is sensitive to light.

When light hits it, specialized cells called photoreceptors transform light energy into electrical signals and send them to the brain. Then the brain processes these electrical signals into images, creating vision.

The earliest form of vision arose in unicellular organisms. Containing simple nerve cells that can only distinguish light from dark, they are the most common eye in existence today.

The ability to detect shapes, direction, and color comes from all of the add-ons evolution introduces to these cells.

Two Major Types of Eyes

Two major eye types are dominant across species. Despite having different shapes or specialized parts, improved vision in both eye types is a product of small, gradual changes that optimize the physics of light.

Simple Eyes

Simple eyes are actually quite complex, but get their name because they consist of one individual unit.

Some mollusks and all of the higher vertebrates, like birds, reptiles, or humans, have simple eyes.

Grid of photos showing examples of simple eyes in the animal kingdom

Simple eyes evolved from a pigment cup, slowly folding inwards with time into the shape we recognize today. Specialized structures like the lens, cornea, and pupil arose to help improve the focus of light on the retina. This helps create sharper, clearer images for the brain to process.

Simple eye evolution

Compound Eyes

Compound eyes are formed by repeating the same basic units of photoreceptors called ommatidia. Each ommatidium is similar to a simple eye, composed of lenses and photoreceptors.

Grouped together, ommatidia form a geodesic pattern that is commonly seen in insects and crustaceans.

Grid of photos showing examples of compound eyes in the animal kingdom

Our understanding of the evolution of the compound eye is a bit murky, but we know that rudimentary ommatidia evolved into larger, grouped structures that maximize light capture.

compound eye evolution

In environments like caves, the deep subsurface, or the ocean floor where little to no light exists, compound eyes are useful for producing vision that gives even the slightest advantage over other species.

How Will Vision Evolve?

Our increasing dependency on technology and digital devices may be ushering in the advent of a new eye shape.

The muscles around the eye stretch to shift the lens when staring at something close by. The eye’s round shape elongates in response to this muscle strain.

Screen time with cellphones, tablets, and computers has risen dramatically over the years, especially during the COVID-19 pandemic. Recent studies are already reporting rises in childhood myopia, the inability to see far away. Since the pandemic, cases have increased by 17%, affecting almost 37% of schoolchildren.

Other evolutionary opportunities for our eyes are currently less obvious. It remains to be seen whether advanced corrective therapies, like corneal transplants or visual prosthetics, will have any long-term evolutionary impact on the eye.

For now, colored contacts and wearable tech may be our peek into the future of vision.

Complete Sources

Fernald, Russell D. “Casting a Genetic Light on the Evolution of Eyes.” Science, vol. 313, no. 5795, 29 Sept. 2006, pp. 1914–1918

Gehring, W. J. “New Perspectives on Eye Development and the Evolution of Eyes and Photoreceptors.” Journal of Heredity, vol. 96, no. 3, 13 Jan. 2005, pp. 171–184. Accessed 18 Dec. 2019.

The Evolution of Sight | PHOS.”

Land, Michael F, and Dan-Eric Nilsson. Animal Eyes. Oxford ; New York, Oxford University Press, 2002.

“The Major Topics of the Research Work of Prof. Dan-E. Nilsson: Vision-Research.eu – the Gateway to European Vision Research.” Accessed 3 Oct. 2022.

Continue Reading

Science

Visualizing the Composition of Blood

Despite its simple appearance, blood is made up of many microscopic elements. This infographic visualizes the composition of blood.

Published

on

composition of blood

The Composition of Blood

Have you ever wondered what blood is made up of?

With the average adult possessing five to six liters of blood in the body, this fluid is vital to our lives, circulating oxygen through the body and serving many different functions.

Despite its simple, deep-red appearance, blood is comprised of many tiny chemical components. This infographic visualizes the composition of blood and the microscopic contents in it.

What is Blood Made Up Of?

There are two main components that comprise blood:

  • Plasma – 55%
    Plasma is the fluid or aqueous part of blood, making up more than half of blood content.
  • Formed elements – 45%
    Formed elements refer to the cells, platelets, and cell fragments that are suspended in the plasma.

Plasma

Plasma is primarily made up of water (91%), salts, and enzymes, but it also carries important proteins and components that serve many bodily functions.

Plasma proteins make up 7% of plasma contents and are created in the liver. These include:

  • Albumins
    These proteins keep fluids from leaking out of blood vessels into other parts of the body. They also transport important molecules like calcium and help neutralize toxins.
  • Globulins
    These play an important role in clotting blood and fighting infections and are also transporters of hormones, minerals, and fats.
  • Fibrinogen and Prothrombin
    Both of these proteins help stop bleeding by facilitating the creation of blood clots during wound-healing.

Water and proteins make up 98% of plasma in blood. The other 2% is made up of small traces of chemical byproducts and cellular waste, including electrolytes, glucose, and other nutrients.

Formed Elements

There are three categories of formed elements in blood: platelets, white blood cells, and red blood cells. Red blood cells make up 99% of formed elements, with the other 1% comprised of platelets and white blood cells.

  • Platelets (Thrombocytes)
    Platelets are cells from the immune system with the primary function of forming clots to reduce bleeding from wounds. This makes them critical not only for small wounds like cuts but also for surgeries and traumatic injuries.
  • White blood cells (Leukocytes)
    White blood cells protect our bodies from infection. There are five types of white blood cells with different roles in fighting infections: some attack foreign cells and viruses, some produce antibodies, some clean up dead cells, and some respond to allergens.
  • Red blood cells (Erythrocytes)
    Red blood cells deliver fresh oxygen and nutrients all over the body. They contain a special protein called hemoglobin, which carries oxygen and gives blood its bright red color.

The lifespan of a typical red blood cell is around 120 days, after which it dies and is replaced by a new cell. Our bodies are constantly producing red blood cells in the bone marrow, at a rate of millions of cells per second.

Abnormal Red Blood Cells

Normal red blood cells are round, flattened disks that are thinner in the middle. However, certain diseases and medical therapies can change the shape of red blood cells in different ways.

Here are the types of abnormal red blood cells and their associated diseases:

composition of blood

Sickle cell anemia is a well-known disease that affects the shape of red blood cells. Unlike normal, round red blood cells, cells associated with sickle cell disease are crescent- or sickle-shaped, which can slow and block blood flow.

Other common causes of abnormally shaped red blood cells are thalassemia, hereditary blood disorders, iron deficiency anemia, and liver disease. Identifying abnormal blood cells plays an important role in diagnosing the underlying causes and in finding treatments.

The Functions of Blood

We know that blood is vital, but what does it actually do in the body?

For starters, here are some of the functions of blood:

  • Blood transports oxygen to different parts of the body, providing an energy source. It also delivers carbon dioxide to the lungs for exhalation.
  • The platelets, white blood cells, and plasma proteins in blood play an important role in fighting infections and clotting.
  • Blood transports the body’s waste products to the kidneys and liver, which filter it and recirculate clean blood.
  • Blood helps regulate the body’s internal temperature by absorbing and distributing heat throughout the body.

While we all know that we can’t live without blood, it serves many different functions in the body that we often don’t notice. For humans and many other organisms alike, blood is an integral component that keeps us alive and going.

Continue Reading

Subscribe

Popular