from the world's big
Life forms on Earth are wildly varied, but scientists discover a single formula that predicts every one's life cycle.
- Earth's species diversity is stunning, but there are a couple of battles we all face.
- Our response to these challenges set the course of our lives.
- Plug in a couple of variables, and a new formula predicts how we live, reproduce, and die.
Our common struggles<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMjE2NDI0OS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYxNzU5MTYyNn0.CItlv_weyCrvuIgIyt1PCvDTPlcN668DqcRZjWwLQos/img.jpg?width=1245&coordinates=0%2C49%2C340%2C291&height=700" id="d3ae8" class="rm-shortcode" data-rm-shortcode-id="0174b4109c5c9743ebf2eca44189e0e0" data-rm-shortcode-name="rebelmouse-image" />
Image source: Budimir Jevtic/Shutterstock<p style="margin-left: 20px;"><em>"The life histories of animals reflect the allocation of metabolic energy to traits that determine fitness and the pace of living. Here, we extend metabolic theories to address how demography and mass–energy balance constrain allocation of biomass to survival, growth, and reproduction over a life cycle of one generation." — Burger, et al</em></p><p>These challenges present themselves in different ways in different habitats, and so our responses vary. Nonetheless, we all aspire to survive for a while, reproduce, and get out of the way of our offspring. Whether one is a turtle laying millions of eggs on a beach or an elephant giving birth to one calf at a time, our goals are essentially the same.</p><p>The study begins with an axiom: "Energy is the staff of life." The sustainable allocation of energy is therefore something all species need to establish in order to survive. According to the study, there are two areas in which workable tradeoffs have to be found for any creatures:</p> <ol> <li>A "mass–energy balance. . . so that over a lifespan in each generation, all of the energy acquired. . . is expended on respiration and production, and energy allocated to production exactly matches energy lost to mortality."</li> <li>A "constraint on mortality so that, regardless of the number of offspring produced, only two survive to complete a life cycle of one generation."</li> </ol>
Predicting a species’ life cycle<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMjE2NDI1NS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY0MDQ3MDA5NH0.PlUP9AwfCh22BqkACVKYu5LSzotuzyIbJbZ4SxUCz4o/img.jpg?width=980" id="f976e" class="rm-shortcode" data-rm-shortcode-id="3f741d2773d967454e7c875497f17101" data-rm-shortcode-name="rebelmouse-image" />
Image source: Ihnatovich Maryia/Shutterstock<p>Burger and his colleagues derived a predictive formula informed by a species' response to the two constraints.</p><p>"What's so cool about these equations," says Burger, "is that to solve it, all you have to know are two values — the size of the offspring at independence and the adult size. If you plug that into the equation, you get the number of offspring an organism will produce in a lifetime [as well as] myriad other life history characteristics."</p><p>Assembling and analyzing a database of 36 animals' life histories, Burger and his colleagues were able to create a formula that can accurately predict a number of things about any species' life story:</p> <ul> <li>the length of a species' single generation</li> <li>the species' mortality rate</li> <li>the number of offspring the species reproduces and the size of the offspring</li> <li>the type and extent of parental care common to the species</li> </ul> <p>Prior to the new study, the only widely used formula had been the notion that the smaller the offspring the more of them there were, and vice versa. Burger's finding indicate that things are not quite that simple.</p><p>The new formula is of more than academic importance. As we work to understand habitat changes caused by humankind and the species they impact, and as we seek to help those species survive, knowledge of their natural life cycles is invaluable, particularly given the incredible variety of life forms involved, many of whose life stories remain largely hidden from us.</p><p>"We now need to put these equations to practice," asserts Burger, "by developing user-friendly programming tools, collaborating with field scientists refine ecosystem models and informing management decisions."</p>
Men should be just concerned as women.
- A study from Rutgers documents age-related reproductive factors for men.
- Beyond a certain age, men risk a variety of serious hazards to their mates and offspring.
- Men planning to father children should consider banking their sperm before reaching 35.
Risking the health of loved ones<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTQ2NzcwNi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY0NzgyNDM3MH0.WlJDUc1wryzth9MkKAs7PStRIPOvIpXZ39HMcJKv7No/img.jpg?width=980" id="7971a" class="rm-shortcode" data-rm-shortcode-id="4f48ea95f663221539391d7e1dcdbabe" data-rm-shortcode-name="rebelmouse-image" />
Image source: Janko Ferlič/Unsplash<p>According to the study, men 45 and older risk a range of hazards:</p> <ul> <li>The put their partners at increased risk of experiencing pregnancy complications: These include gestational diabetes, preeclampsia, and pre-term delivery.</li> <li>Infants of such fathers are more frequently born with issues: They're more apt to be premature or succumb to late stillbirth. Low birth weight, a greater prevalence of newborn seizures and birth defects are also more likely to occur. The report cites cleft palate and congenital heart disease as among these defects.</li> <li>Maturing children continue to have problems: These include a higher incidence of childhood cancer, cognitive and psychiatric disorders, and autism. "Although it is well documented that children of older fathers are more likely to be diagnosed with schizophrenia — one in 141 infants with fathers under 25 versus one in 47 with fathers over 50 — the reason is not well understood," says Bachmann. The risk of autism decreases with fathers under 25, increases at 30, stabilizes at 40, and again rises at 50.</li></ul>
Fatherhood outside the window<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTQ2NzcxMi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyMzQ1ODgyNH0.QKXDRSjOCH8_zit8K_uT9beKC6OXeAQb8fHl8SqYaFk/img.jpg?width=980" id="907bb" class="rm-shortcode" data-rm-shortcode-id="e6431ebd8db53fc3b0520b5d66716af1" data-rm-shortcode-name="rebelmouse-image" />
Image source: olliulli/Shutterstock<p>The main issue seems to be a degradation with age of the quality of sperm. In the same way that fitness fades with age for the individual, sperm also declines. While there's not yet a consensus on the point at which "advanced paternal age" sets in, and more research is needed, the range is somewhere between 35 and 45 years of age.</p><p>Whenever it is, older men have a reduced sperm count and the quality of an offspring's inherited DNA may be sub-optimal.</p><p>Bachmann recommends that men planning to produce offspring later in life bank their sperm before hitting 35 for subsequent insemination when the time is right.</p><p>The study refers, of course, to reproduction and has nothing to say about being an older father of a partner's child with a previous mate or an adopted child.</p>
Here's the first evidence to challenge the "fastest sperm" narrative.
AI is capable of self-reproduction—should humans be worried?
Those among us who fear world domination at the metallic hands of super-intelligent AI have gotten a few steps ahead of themselves. We might actually be outsmarted first by fairly dumb AI, says Eric Weinstein. Humans rarely create products with a reproductive system—you never have to worry about waking up one morning to see that your car has spawned a new car on the driveway (and if it did: cha-ching!), but artificial intelligence has the capability to respond to selective pressures, to self-replicate and spawn daughter programs that we may not easily be able to terminate. Furthermore, there are examples in nature of organisms without brains parasitizing more complex and intelligent organisms, like the mirror orchid. Rather than spend its energy producing costly nectar as a lure, it merely fools the bee into mating with its lower petal through pattern imitation: this orchid hijacks the bee's brain to meet its own agenda. Weinstein believes all the elements necessary for AI programs to parasitize humans and have us serve its needs already exists, and although it may be a "crazy-sounding future problem which no humans have ever encountered," Weinstein thinks it would be wise to devote energy to these possibilities that are not as often in the limelight.