Were we scavengers rather than hunters?

Bone marrow may have been more important to early humans than meat
Bone marrow may have been more important to early humans than meat

For decades, the theory has been that the emergence of stone tools led early humans (around 2.6 to 3.5 million years ago) to hunt for increasingly larger animals and therefore to eat more meat–and that increase in nutrition led to the increase in human brain size. “Flaked tool use and meat eating became defining characteristics of the Homo genus.”

A newer theory, however, suggests that, instead of hunting and eating meat, early humans used those stone tools to scavenge carcasses left by large predators–to break bones to get at marrow and brain. Bone marrow (fat) may have been more important than the meat (protein) itself; marrow stays fresher longer, is obtained more easily than flesh-meat, does not require as advanced a tool, and is highly nutritious and involved with brain and eye development.

Early humans may have been scavengers rather than hunters …

Read the article (Richard Kemeny, Sapiens, 31 March 2019).

And, go to the source — Origins of the Human Predatory Pattern: The Transition to Large-Animal Exploitation by Early Hominins (Jessica C. Thompson, et al., Current Anthropology, February 2019).

Science highlights: human adult neurogenesis, and a fungus killing amphibians

Growing new neurons in the human adult brain
Growing new neurons in the human adult brain

A new study provides further evidence that the adult brain in humans does grow new neurons (a process called neurogenesis) in the hippocampus–the section of the brain where learning, memory, and mood regulation is controlled. These new brain cells may play a role in depression, PTSD, Alzheimer’s, epilepsy, etc.

Read the article (Karen Weintraub, Scientific American, 25 March 2019).

And, go to the source — Adult hippocampal neurogenesis is abundant in neurologically healthy subjects and drops sharply in patients with Alzheimer’s disease (Elena P. Moreno-Jimenez, et al., Nature Medicine, 25 March 2019).

B dendrobatidis is infecting and killing amphibians worldwide

B. dendrobatidis or Bd is a fungus that infects the skins of amphibians (frogs, toads, salamanders, newts, etc.) and then kills them. Bd has been around since at least the 1980’s, but only recently has research quantified that Bd has caused declines in 500 amphibian species globally–more than 40% of those species are now extinct or have lost more than 90% of their population.

Read the article (Stephanie Pappas, Scientific American, 28 March 2019).

And, go to the source — Amphibian fungal panzootic causes catastrophic and ongoing loss of biodiversity (Ben C. Scheele, et al., Science, 29 March 2019).

Science highlights: threats to global health, and apple trees are dying

Air pollution is one of the greatest threats to people's health worldwide.
Air pollution is one of the greatest threats to people’s health worldwide.

See the WHO’s 10 threats to global health in 2019. Diabetes, cancer, and heart disease account for more than 70% of all deaths globally–driven by tobacco use, physical inactivity, alcohol abuse, unhealthy diets, and/or air pollution and climate change. These factors also drive mental illness; half of all mental illness starts by age 14, suicide is the second leading cause of death among 15-19 year-olds.

(World Health Organization, 21 March 2019).

Rapid Apple Decline is killing young apple trees in North America
Rapid Apple Decline is killing young apple trees in North America.

“Rapid/sudden apple decline”–where rows of young apple trees quickly die–is occurring and spreading in North Carolina, Pennsylvania, New York, British Columbia, and elsewhere in North America. No certain cause has yet been found–weather-related stress (severe cold and drought), certain root stocks, herbicides, unknown pathogens, insects, and/or high-density planting may play a role. Apples are a very valuable crop–worth $4 billion in the U.S. alone.

Read the article (Erik Stokstad, Science, 21 March 2019).

Getting kids hooked on sugary beverages

Getting kids hooked on sugary beverages

The prevalence of obesity in the United States among those 40-59 and over 60 years of age is an extremely high 41-43% and about 19% for those under 20 (as of 2016). Rates of type 2 diabetes are rapidly increasing today for adolescents.

How did we get to this point?

One way–big Tobacco companies bought up food companies and manipulated and marketed heavily sweetened/artificial flavor beverages (like Tang, Capri Sun, Kool-Aid, and more) to children from the 1960’s through the early 2000’s (many of these brands have now passed to other companies … who are continuing this marketing today in the U.S. and globally).

“Cigarette companies were frequently introducing new flavored products, and many of the chemicals that went into cherry-scented chewing tobacco and apple-flavored cigarettes [as examples] found their way into children’s drinks.” The goal of these manipulations and marketing was “to leave people wanting more.”

People were hooked on sugary beverages. The very adult age groups in the United States with obesity rates in the 40% range today were children in the 1960’s, 1970’s and 1980’s.

Read the article (Andrew Jacobs, New York Times, 14 March 2019).

Trending science on Twitter (winter 2019)

Science and Twitter

Based on an analysis of the Twitter sites, Science Headlines and Headline Science, these were the topics that people were most and least engaged in between January and mid March 2019:

Most engaged:

  1. Rising sea levels
  2. Wasting food
  3. Limits to accurate weather forecasting
  4. Why do we crave sweets when stressed?
  5. Inflammation and Alzheimer’s/Parkinson’s

Least engaged:

  1. Increasingly unhealthy fast food
  2. Prejudice, empathy, and psychology
  3. Job automation
  4. Plastic waste
  5. Consumer ancestry and DNA testing

(Kevin Engel, 18 March 2019).


Science highlights: insomnia, and maternal mortality

Recent research has probed the biological basis of insomnia.
Recent research has probed the biological basis of insomnia

Sleeplessness is a big problem today; its costs from health problems to lost productivity are huge. Recent research has probed the biological basis of insomnia. From analysis of the genomes of over 1.75 million people, insomnia has been potentially linked to hundreds of genes, specific brain regions, and an overlap with mood disorders (depression, anxiety, etc.).

Read the article (Simon Makin, Scientific American, 12 March 2019).

Maternal mortality in the United States is the highest among all developed countries.
Maternal mortality in the United States is the highest among all developed countries

Approximately 800 women in the U.S. die each year during pregnancy and within 42 days after delivery–all developed countries have a lower maternal mortality rate. More than 60% of these deaths are preventable; the main causes of death vary by race. Suicide, homicide, and drug overdoses are the cause of many postpartum deaths.

Read the article (Anita Slomski, JAMA, 13 March 2019).