Why Save Species From Extinction?

Extinction is a normal part of the process of evolution – its counterpart being speciation, in which new species emerge, or more accurately, diverge. It is not the place of humans to try to control nature, but we are putting an enormous extinction pressure on the environment (hence the nickname Homo destructus). It’s about time we put our money and effort into conserving the unique species we have left, before it’s too late.

CRITICAL-CONDITION-12-EXTREMELY-RARE-AND-ENDANGERED-ANIMALS1

Just a few of the world’s most critically endangered species

Humans have caused a huge number of extinctions in recent history, and we continue to do so today. Our forager ancestors managed to wipe out the largest animals on every island they migrated to, including Australia, the Americas, Madagascar and the Galapagos. This doesn’t mean we’re off the hook, it means we are already in big trouble! Current extinction rates across the globe are severely high – comparable to the five mass extinctions that have occurred in the past 600 million years. Previously, the triggers were large asteroids colliding with the earth, volcanoes or severe climate change causing epic inhospitable winters, wiping out as much as 90% of the existing species at that time1. These extinction events may have taken tens of thousands of years, yet we’re causing noticeable, irreversible change within just a few hundred1. Never before has an extinction of millions been caused by one, single species2. Us.

We are causing a sixth mass extinction. And it is our responsibility to prevent this atrocity.

Won’t a mass extinction free up ecological niches and allow a novel evolutionary diversification?

Yes, this has been known to happen in the past. But previously it took anywhere from 5 – 30 million years for biodiversity to recover to pre-extinction levels1.

How do we cause extinctions?

  • Hunting and exploitation: Big game, known as megafauna, have been killed all across the world for meat and for trophies. Overfishing and trawling continue to cause unimaginable declines in the world’s aquatic ecosystems.
  • Destruction of habitat: Huge declines in forests provide cleared land for agriculture or urban areas (see figure).
  • Invasive species: Moving species (accidentally or deliberately) to foreign locations where they decimate local populations of endemic species.
  • Climate change: Many species can’t adapt or migrate fast enough to the rapidly changing climate.

ForestCover

Comparison of the forest cover from 8,000 years ago to 2005

Our Responsibility

There’s 7.37 billion (and counting) of us straining planet Earth’s precious resources to their limits. We are all responsible for the decline and loss of each species, each distant (or close) cousin that we share this home with. Therefore, we are 100% responsible for saving the many, many species that we’re driving extinct.

Biodiversity, the varieties of life, is the most valuable, extraordinary thing on this planet (and perhaps the universe) so it’s our duty to stop indiscriminately wiping it out. We must finally display the wisdom our species, Homo sapiens, is meant to possess, by saving and restoring the planet’s ecosystems and their exquisite inhabitants.

References

  1. How Long Does Mass Extinction Take? By Helen Thompson on Smithsonian.com
  1. How To Survive The Sixth Mass Extinction. By Grennan Milliken on PopularScience.com

Images

Critically Endangered Species Image from WebEcoist.

Deforestation Figure from Global Greenhouse Warming.

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Cancer Misconceptions

There are a number of misconceptions I believe some people have about cancer, which I thought I would attempt to clear up.

  1. All cancers are alike
  2. We should find a cure for cancer soon
  3. Getting cancer is unlucky
  4. Cancer is a man-made disease

 

1. All cancers are alike

By using the term cancer we tend to think of it as a single illness, with a range of risk factors, such as smoking, eating unhealthily, drinking alcohol to excess and being exposed to radiation. But from a biological standpoint, cancers vary hugely, with over 200 types of cancer, and subtypes that vary drastically. All cancers are the result of abnormal cell growth. Normally, growth of our cells is controlled by oncogenes, promoting it, and tumour suppressor genes, inhibiting it. But occasionally a mutation will arise in a critical gene, which various safeguard mechanisms attempt to identify – so they can correct the mistake or else instruct the cell to self-destruct. However, very occasionally a mutation is missed by the safeguards (or the mutation is in a gene for the safeguards themselves!) and the abnormal cell can start growing uncontrollably; replicating, spreading, mutating and evolving as cancerous tissue1.

Almost all cancers are caused in this way, but the precise genetic fault that causes the cell to start growing abnormally and avoid self-destruction can be one of many thousand, or even million! As with any existing complicated system, the vast majority of changes will be detrimental to its function. Even in the same tissue type, there can be numerous different kinds of cancers, with very different causes. But cancers can start to grow in any tissue type in the body, and these usually differ substantially from one another. This brings us on to misconception number 2.

 

2. We should find a cure for cancer soon

Cancers vary widely in their causes and this means that there will never be a ‘cure for cancer’. Compared to most diseases cancers are incredibly difficult to treat because the cause is the body’s own cells, growing uncontrollably. Once it has begun there is almost no stopping it, as the body is unable to recognise the cancerous tissue as being a threat, as it has the “self” marker that foreign pathogens causing other diseases lack. Attempts at fighting the cancer by doctors are similarly thwarted – it is difficult to target the abnormal cells alone, hence why chemotherapy typically causes harmful side effects.

On top of this, a single cancer tumour has a whole succession of mutations, varying by location in the tumour, plus a tendency to mutate rapidly. Treatments can be aimed at the genetics of a sample unrepresentative of the entire tumour, and drug resistance can quickly emerge if a drug fails to destroy every cell quickly enough. As with other diseases that can evolve resistance to antibiotics, cancers can quickly mutate and overcome our most effective treatments2. Doctors compensate by administering a huge dose and combination of different drugs during chemotherapy, reducing the odds that the tumour will become resistant to the treatment. Unfortunately, the large dosage also contributes to the severe side effects that many cancer patients experience.

It is likely that many cancers will prove to be incurable, but by concentrating our efforts on the most common killers, we may hopefully be able to cure some of them in future. However, I think it is unlikely that cancers will ever stop being a leading cause of death. If you look at causes of death over the past couple of hundred years you can see that cancers have increased hugely. This rise in cancers can be attributed to people living longer due to improved sanitation, nutrition and medical care. No longer are infants lucky to make it to their teenage years, and no longer are adults lucky to make their 60th birthday. But unfortunately cancers become much more likely in old age, and this leads us on to misconception number 3.

 

3. Getting cancer is unlucky

The average life expectancy in the UK today is 81, which by the standards of any of our ancestors is incredibly long! While we are no longer likely to die from infectious diseases like diarrhoea, pneumonia and tuberculosis, which killed many of our ancestors, we are now more prone to developing a cancer. The reason for this is simple; cancers are caused by genetic mutations and these accumulate over time from mistakes in DNA copying (in cell cycles) and exposure to environmental risk factors. Now that we are lucky to live longer lives, we are much more likely to get and die from cancer.

According to Cancer Research UK, 1 in 2 people in the UK born after 1960 will develop cancer in their lifetime2. So getting cancer is just as unlucky as losing a coin toss. However, it should be recognised that lifestyle and environmental risk factors play a vital role too. Behaviours such as smoking, drinking, failing to exercise, eating a poor diet and getting sun burnt can vastly increase your chances of developing a cancer. So you obviously shouldn’t think of cancer as inevitable and throw caution to the wind!

While cancer is terrible as it takes many of us to our graves, it is actually a sign that we are living long lives in the first place. It should be noted that some cancers do strike people while they are young, but these are quite rare cases (less than 2% of all UK cancer cases are in under 25’s2). Why are cancers more common when we are older? Because there was a strong selective pressure for people to live to rear offspring, and to care for those offspring until they reached reproductive age in turn. So there was a strong pressure for people not to get cancer and die at a young age, before passing on their genes – those that failed left no offspring and those that succeeded were our ancestors. In contrast, the selective pressure on our ancestors to stay alive and be free of disease into old age was very relaxed. If a genetic disease doesn’t strike until we are 50, then it won’t be rapidly selected out of the population, as our children will already be passing on our genes!

All organisms face a trade-off in allocating energy to different aspects of their lives – growth, reproduction and maintenance (immune system and repair). Natural selection has led to strategies that produce optimal allocations of their resources, on average, resulting in a maximum possible number of strong, healthy offspring (biological fitness). The body spends energy defending itself against environmental, as well as genetic, factors that can trigger cancer, such as sunlight, viruses, bacteria and carcinogens. It pays to invest large amounts of energy supressing mutations that could lead to cancer in early and reproductive years, but the payoff to this maintenance reduces dramatically post-reproduction3.

There are so many different possible forms of cancer that we could get, and our chances increase rapidly as we age. Unfortunately, it is not bad luck if you get cancer and die from it in old age; that is how many of us can expect to die. Improved nutrition and medicine are allowing us to live longer and longer lives, and it is estimated that a third of all babies born today in the UK will live to be over 1004. However, even with great advances in genetic therapies, cancers will always be a huge difficulty to overcome; one that we may never be able to beat. So it is possible that many of us will live for over 100 years, but it is not very likely that we’ll be able to stay free of cancer forever.

 

4. Cancer is a man-made disease

This is absolute nonsense. The entirety of multi-cellular life has the ability to get cancer, and many other animals do get cancer; if they are lucky enough not to get injured, diseased or eaten before they get old.

A more accurate statement is that cancer is more common in modern times. Some environmental risk factors for cancer such as smoking, drinking alcohol, eating unhealthily and air pollution are no doubt more common in modern society. But the main reason cancer is more common is that we live longer lives; our bodies deteriorate with exposure to carcinogens and our cellular defences against cancer can’t protect us forever.

 

Special thanks to Jonathan Lockett, my cancer expert, for his technical knowledge and tips.

 

  1. Casás-Selves, M., & DeGregori, J. (2011). How cancer shapes evolution, and how evolution shapes cancer. Evolution4(4), 624–634. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3660034/
  2. Cancer Research UK http://www.cancerresearchuk.org/cancer-info/cancerstats/keyfacts/Allcancerscombined/
  3. Aktipis, C., & Nesse, R. M. (2013). Evolutionary foundations for cancer biology. Evolutionary applications6(1), 144-159. http://www.athenaaktipis.com/Home_files/AktipisNesse2013.pdf
  4. Office for National Statistics http://www.ons.gov.uk/ons/rel/lifetables/historic-and-projected-data-from-the-period-and-cohort-life-tables/2012-based/sty-babies-living-to-100.html

Guest Post For Nature’s ‘Eyes On Environment’ Blog

Eyes on EnvironmentJust had my first guest blog post published on one of Nature’s Scitable blogs called ‘Eyes on Environment’.

Unique and Alone on the EDGE of Existence
How to maximise biodiversity when resources are limited: calculating priority species in conservation.

Have a read!

http://www.nature.com/scitable/blog/eyes-on-environment/unique_and_alone_on_the?isForceDesktop=Y

Are Religions Evolving?

Last night Dr Mike Taylor came to Malmesbury Abbey to talk about Dinosaurs and God (see pic). A self-proclaimed ‘armchair Palaeontologist’, with a PhD no less, he spends his spare time trawling through fossils in museums across the world. He has particular fondness for the long-necked dino’s called Sauropods, two of which he has been able to name – Xenoposeidon proneneukos meaning “alien earthquake god” and Brontomerus mcintoshi meaning “thunder-thighs”. These choices of names perhaps reflect his controversial belief that taxonomy is merely an art. Besides this, the reason for Mike’s talk was that he is an avid Christian who believes science and his (blind) religious faith can co-exist in harmony, and don’t contradict one another.

Image

Now as a scientist and definite non-believer I find his position quite baffling. I am sure that science can and does answer every single question about how life on Earth (and we humans) came to be here, so I see no need to bother with religion. Mike also fully appreciates the power of the scientific method but argues that there are some questions it cannot hope to answer – what these might be is not quite clear. He is very sure of the evolution of all animals and humans, but suggests that at some point in our relatively recent evolutionary past God recognised that we look close enough to ‘his image’ and waved his magic over us, raising us from mere animals to some higher status that we now enjoy. Mike argues that we are moral, responsible, merciful, forgiving and that these things set us apart from all other animals, contrary to the clear evidence that we are nothing more than a particularly strange ape.

I’m not trying to cause offence, but it’s hard to see why someone who accepts the evidence for evolution needs any further explanation for how and why we got here. Religion seeks to give answers to the ‘meaning’ and ‘purpose’ of life and being human, but science adequately answers these questions; most people just don’t like to accept the answers it gives. There is no great ‘meaning’ of life, we are here by chance and the only ‘purpose’ we and all other living things have is to produce replicates of ourselves, thereby propagating our genes and outcompeting our rivals. Perhaps this truth is just too anti-climactic for most to accept and therefore religions have flourished by filling people’s need for something more. Being scientifically enlightened does not make you feel empty and meaningless; it fills one with awe, excitement and curiosity as the wonders of life itself are revealed.

As science continues its unquenchable desire to explain, it is constantly putting pressure on religious beliefs, by falsifying them. Their only strategy to survive as a religion is to adapt and admit that certain passages (more and more it would seem) are not meant to be literal historic accounts but are poetic stories with hidden messages. After countless attempts to scupper the advances of evolutionary thinking, religious groups are finally starting to accept that fighting against science is simply hopeless. The result is that people like Dr Taylor are helping to promote the marriage between science and religion. In this way they hope that their faith can continue despite the mounting evidence that there is no need for religion, as everything is comfortably explained by science. Ironically then, religions are now being forced to ‘evolve’ to stay relevant and maintain the appeal of increasingly educated people, most of whom rightly accept science as fact.

Unfortunately, religion will always be able to fall back on the personal nature of ‘belief’ and the impossibility of disproving the existence of (a) God. But with some luck and much quality education, soon parents and their children won’t see any need for religion when science can successfully explain everything there is to know about life on Earth and Homo sapiens.