‘Tree of Life’ going extinct

Here’s a report that’s both alarming and so “global” that I wonder what I, as an individual, could do about it. So … here’s a fact-based report. Then, I’ll add (with D’s guidance) some specific things each of us can readily do.


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Scientists warn entire branches of

the ‘Tree of Life’ are going extinct




September 18, 2023


Humans are driving the loss of entire branches of the “Tree of Life,” according to a new study published on Monday which warns of the threat of a sixth mass extinction.

Gerardo Ceballos, professor at the National Autonomous University of Mexico, and co-author of the study published in Proceedings of the National Academy of Sciences (PNAS), said …


“The extinction crisis is as bad

as the climate change crisis. It

is not recognized. What is at

stake is the future of mankind.”


The study is unique because instead of merely examining the loss of a species, it examines the extinction of entire genera.

In the classification of living beings, the genus lies between the rank of species and that of family. For example, dogs are a species belonging to the genus canis — itself in the canid family.

Robert Cowie, a biologist at the University of Hawaii who was not involved in the study, told AFP …


“It is a really significant contri-

bution.  I think the first time

anyone has attempted to as-

sess modern extinction rates

at a level above the species.”


Anthony Barnosky, professor emeritus at the University of California, Berkeley, agreed …


“As such, it really demonstrates the

loss of entire branches of the Tree

of Life, a representation of living

things first developed by Charles

Darwin. The study shows that we

aren’t just trimming terminal twigs,

but rather are taking a chainsaw

to get rid of big branches.”


– 73 extinct genera –

The researchers relied largely on species listed as extinct by the International Union for Conservation of Nature (IUCN). They focused on vertebrate species (excluding fish), for which more data are available.

Of some 5,400 genera (comprising 34,600 species), they concluded that 73 had become extinct in the last 500 years — most of them in the last two centuries.

The researchers then compared this with the extinction rate estimated from the fossil record over the very long term. Ceballos explained …


“Based on the extinction rate

in the previous million years

we would have expected to lose

two genera. But we lost 73.”


That should have taken 18,000 years, not 500, the study estimated — though such estimates remain uncertain, as not all species are known and the fossil record remains incomplete.

The cause? Human activities, such as the destruction of habitats for crops or infrastructure, as well as overfishing, hunting and so on.

The loss of one genus can have consequences for an entire ecosystem, argued Ceballos. He said …


“If you take one brick, the wall

won’t collapse. You take many

more, eventually the wall will

collapse. Our worry is that we’re

losing things so fast, that for us it

signals the collapse of civilization.”


– ‘Still time’ to act –

All experts agree that the current rate of extinction is alarming — but whether this represents the start of a sixth mass extinction (the last being the asteroid that wiped out the dinosaurs 66 million years ago) remains a matter of debate.

Scientists broadly define a mass extinction as the loss of 75 percent of species over a short period of time. Using that “arbitrary” definition, Cowie said, a sixth mass extinction has not yet occurred.

But if we assume that “species will continue to go extinct at the current rate (or faster), then it will happen,” he warned.


“We can surely say that this

is the beginning of a poten-

tial sixth mass extinction.”


Ceballos warned that the window of opportunity for humans to act is “rapidly closing.”

The priority is to halt the destruction of natural habitats, and to restore those that have been lost. He said …


“But there is still time to

save many genera. There are

5,400 genera, we can save

many of them if we act now.”


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I’m not a biologist.  So, I quickly turned to D for recommendations of things each of us can easily do that could make a significant difference …

“First and foremost is to help protect federal, state and local ‘Wild places.’  These could be anything from deserts to waterways.  All ecosystems need our help.  By protecting, it could mean donating time or it could mean donating money.  Land trusts also protect remaining wild areas in our world.  Urban sprawl, aka suburbia, is one of the biggest takers of land.  So, if you’re going to move, think about and please do not support – and maybe even fight – large residential developers coming into your area and clear-cutting land. 

“On your own property, plant native vegetation, to allow all creatures to exist in a manner that is consistent with your local eco-systems.  And seriously, plant more trees!  Trees are the heart of most eco-systems. And while trees will be different in different parts of the world, they all provide food, shelter, nesting spaces, resting spaces, and shade for all kinds of native critters. 

“In addition, please remove grass lawns; they provide almost nothing toward supporting native animals, birds, or reptiles.  Then, replace your grass with native plants and trees.”


When I look at subdivisions – even new developments with new homes – people or any other critters are rarely outside. There’s no privacy!  In slightly older subdivisions, I notice that the path to the front door is covered by grass, as no one uses the front door, due to the lack of privacy.  I also see people spending hour upon hour mowing and edging their lawn – or spending their money on lawn maintenance services.

If we need an area for recreation – an outdoor carpet, essentially – for sports, then a mowed lawn is useful.  Otherwise, your local nursery can recommend a number of plants that can cover and stabilize the soil in your yard.  For example …

I used golden-tipped junipers that cost very little when they’re small.  (Maybe $7 or so, with each plant eventually covering about 10-15 square feet.)  Within two years, our yard was covered.  After four years, we had a dense groundcover that required no watering whatever, and only an hour or so, once or twice a year, to search for and remove any weeds.  Its aesthetic is far more interesting and inviting than a plain grass “green carpet.”  The soil is healthier. And little critters can roam in and among those plants.

Developers seek the cheapest way to cover the soil, usually grass sod; they don’t have the yard maintenance expense. As they don’t live in their developments, continuing costs are left to homeowners.  And chemicals used to eliminate lawn weeds hurt our ecosystems, and the critters who live there.

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