Tag Archives: biology

Lengthy Post: Races, Historical and Modern

Race, a controversial topic, has been the reason for hate crime, genocide, discrimination, disenfranchisement and other atrocities. But what is race really? Race appears to be a human method for classifying other groups of humans, distinguishing “us” from “them”. Most determinants of race are outward physical traits, namely facial features, build and skin color. The last feature, skin color, is a prominent distinguishing feature of the races, which have been separated in color groups. Historically, the Caucasian peoples have been associated with white, East Asian peoples with yellow, North African, Middle Eastern and South Asian peoples with brown, Sub-Saharan and Australian Aboriginal peoples with black and Amerindian peoples with red. Still another racial definition is based on ancestral homelands. Caucasian people from Europe, North Africa, the Horn of Africa, the Middle East and Central and South Asia, Negroid people (these are historical terms, you can expect racism) from Sub-Saharan Africa and Australia, Mongoloid people from East, South East, North, and Central Asia, the Americas, the Arctic and some Pacific islands. Recent genetic research has uncovered some evidence of separate races, but based on adaptations to a homeland while retaining inter-race breeding capability (every different race is still part of the same species). A 1994 study set up 9 potential races: African, New Guinean & Australian, Pacific Islander, Southeast Asian, Amerindian, Arctic Northeast Asian, Northeast Asian, European Caucasoid and Non-European Caucasoid. Racial studies continue to be controversial, but perhaps through studying race we might learn it doesn’t exist.

Advertisements

Leave a comment

Filed under Biology, Culture, Science

Double Post From the Archives: Sharks (August 14 & 15)

Sharks are arguably the oldest family of large animals still alive, with the oldest accepted shark fossil being about 420 million years old, predating the dinosaurs, land animals, and even land plantlife. Sharks as a group have survived four major mass extinctions, each of which had killed at least 70% of all species then living on the planet. Sharks have a great sense of smell, able to detect blood in a concentration of one part per million (for every drop of blood, there are 1 million drops of water), and they have another sense called electroreception, which allows them to detect Earth’s magnetic field…and any movement of nearby prey. Only four shark species (great white, tiger, bull and oceanic whitetip) produce a significant number of fatal shark attacks. Sharks in general, and those four in particular, are the top predators of their environment, and like many other natural hunters, are curious of unfamiliar creatures (read: humans). However, they lack any means to explore the unknown other than their mouth, which can explain some shark attacks considering humans are generally not sufficient prey to warrant feeding as a reason to attack. On average, there is less than one death from a shark attack each year while there are, on average, forty deaths from lightning strike. Finally, the eggs of the grey nurse shark hatch inside the mother and when the first embryo develops, it eats its sibling’s embryos and any unhatched eggs. Talk about sibling rivalry.

Leave a comment

Filed under Biology, From the Archives, Science

Historical Bad@$$: George de Hevesy

George Charles de Hevesy was a 20th century chemist born in 1885 into a Hungarian Jewish family. During his life he became an acquaintance of Neils Bohr and worked in Ernest Rutherford’s laboratory. Along with the Dutch physicist Dirk Coster, de Hevesy discovered hafnium, and developed a method for the use of plutonium-212 as a chemical tracer, allowing chemists and biologists to follow chemical and biological processes as they happened. de Hevesy won the 1943 Nobel Prize in Chemistry for his work on radioactive tracers. But this is the most bad@$$ part, in WWII de Hevesy took the Nobel Prizes of James Franck (a German Jewish physicist) and Max von Laue (an opponent of the Nazi party), and hid them in the Niels Bohr Institute Laboratory where he worked, so that they wouldn’t be taken by Nazi German forces…and he dissolved both solid gold medals in aqua regia (one of the few acids that can dissolve gold). After the war, de Hevesy precipitated the gold back out from the acid and returned the gold to the Nobel Society to have the medals recast.

1 Comment

Filed under Historical Bad@$$, History, Science

Chromosomes

Chromosomes. Everyone has them, every living thing with a nuclei in their cells has them. Every plant, every animal, every fungus and a selection of microbes has/have chromosomes. Basically, all of the genetic information of an organism with chromosomes is stored in the chromosomes (except mitochondrial DNA, but that’s weird stuff and is arguably not part of the organism’s genome) which, during cell division, bunch up and double up so they look like tiny, fat X’s. Many organisms have an even number of chromosomes, largely due to the nature of sexual reproduction, which requires an even number of chromosomes to form sex cells, but the range of the number of chromosomes any organism has varies widely based on species. For example, humans have 46 chromosomes, the same as the Reeves’s muntjac and Sable antelope. wolves, jackals, dogs and chickens all have 78 chromosomes, shrimp and two rat species have around 92, gypsy moths and giraffes both have 62, zebrafish and rice have the same number of chromosomes, 24. The organism with the most chromosomes is the Adders-tongue plant, with over 1,000 chromosomes (one Wikipedia page says 1440, another says 1262, so I’m just being vague), and the organism with the least chromosomes (not counting those without them) is the male Jack jumper ant, which has a single chromosome due to ant sexual behaviors (female jumper ants have a normal number of chromosomes for their species, 2).

Leave a comment

Filed under Biology, Science

The Ballsiest Animals

Warning: the following post concerns the male gonads (testicles) and the creatures they are attached to.
Let’s start with bats. Bat testes range any where from .12% to 8.4% of body mass, the widest range of any group mammals (for comparison, primate testes range from .02% to .75% of body mass). Also, when many females are around, bat testes enlarge while the bat’s brain shrinks, and the reverse occurs when few females are around. What bats lack, however, is the distinction of largest testes in relation to body size. That belongs to the bush cricket. Male bush crickets have testes have testes that comprise a whopping 14% of their body mass. Finally we visit the ballsiest vertebrate in the world, not the one with the largest testes, or the strangest, but the most. Most animals tend to have two testes, many jawless fish have only one, but the animal with the most testicles is… the female anglerfish. That’s right. The FEMALE anglerfish. What happens is that female anglerfishes attract their tiny male counterparts which bite into her flesh and atrophy. After some time nothing is left of the males but their testes, producing sperm on-demand, and nothing keeps females from attracting more than one male. No, female anglerfishes have been found with upwards of six parasitic males, that’s more than twelve testes. This parasitic love makes the female anglerfish the ballsiest animal in the world.

Leave a comment

Filed under Biology, Science