There Are More Facts About Eggs Than Possible To Know
August 3, 2020 at 4:20 p.m.
By Max [email protected]
My attitude recently changed, however, when I came across an article in a recent issue of Nature journal that reported on the discovery of a giant soft-shelled egg from the Cretaceous period. A geological period that lasted from about 145 to 66 million years ago.
Previously, the largest known egg belonged to the only recently extinct elephant bird. The egg reported on in Nature was found in Antarctica and exceeds all nonavian dinosaur eggs in volume and differs from them in structure.
The fossil egg was one of the few recovered from a marine environment. It was ovoid in shape and measured 29 x 20 centimeters (cm), which is the preserved length times width. (1 inch is roughly 2.54 cm) Its shell contained roughly 15 consecutive layers of approximately equal thickness. The identity of the animal that laid the egg is unknown, but analyses of known dinosaur species suggest that the egg belonged to an individual that was at least 7 meters (almost 8 yards or 24 feet) long. It may have been a giant marine reptile. Most dinosaurs (including birds), crocodilians and turtles lay hard shelled eggs, by contrast most lizards, snakes and tuatara have a soft eggshell.
Scientists measure egg size and structure to determine the life history characteristics of vertebrates as more than two thirds of all existent amniotes (reptiles, birds and mammals) lay eggs. The structure of an egg is quite complicated, for example, the thickness of the shell may be a strategy to avoid breakage during the incubation of the largest eggs without creating a shell so thick as to inhibit hatching.
Biology
An egg in biological terms is the female sex cell or gamete. In botany, the egg is sometimes called a macrogamete. In zoology, the Latin term for egg, ovum, is frequently used to refer to a single cell, while the word egg may be applied to the entire specialized structure or capsule that consists of the ovum, its various protective membranes and any accompanying nutritive materials. Eggs are laid by female animals of many different species including birds, reptiles, amphibians, and a few mammals. Bird and reptile eggs consist of a protective eggshell, albumen and vitellus (yolk), contained within thin membranes.
Varieties
Most if not all of the eggs we consume come from chickens but the largest egg of common barnyard poultry belongs to the goose. The eggs average 3 to 4.5 inches in length with a circumference of more than 7 inches.
An average goose egg weighs 144 grams (about 5 ounces). The yolk of a goose egg is sometimes as large as a chicken egg, and you can use one goose egg for every two chicken eggs in a recipe. Turkey eggs average between 2 to 2.7 inches in length and are just under 1.5 to 2 inches wide, with an average circumference of 5 inches.
Turkey eggs vary in weight from 66 grams to more than 110 grams. Midget breeds laying the smallest eggs and heritage breeds usually producing the larger eggs. Two turkey eggs will replace three chicken eggs in a recipe.
While an ostrich may lay the world’s largest bird’s egg, it is actually the smallest in proportion to the mother – just 2% of her body weight. Chicken eggs are characterized from their size, from 1.75 to 2.5 ounces.
Chicken Eggs
In 2000, the American Heart Association (AHA) revised its dietary guidelines and gave healthy adults the green light to enjoy eggs once again.
The AHA's guidelines now allow an egg a day for healthy adults while still advising a total daily cholesterol limit of 300 mg. The confusion over eggs stems from their cholesterol content. One large egg contains 213 mg of cholesterol, accounting for two-thirds of the recommended daily limit. Along with milk, eggs contain the highest biological value (or gold standard) for protein. One egg has only 75 calories but 7 grams of high-quality protein, 5 grams of fat, and 1.6 grams of saturated fat, along with iron, vitamins, minerals, and carotenoids.
Odd Facts
Although a hen has only one exterior opening (the cloaca or vent) for egg laying and elimination, eggs are not contaminated during the laying process.
Two separate channels, the oviduct and the large intestine, open into the cloaca. As the egg nears the end of the oviduct, the intestinal opening is temporarily blocked off and the egg pass through the cloaca without contact with waste matter. Hens do not usually lay eggs in the dark, so once a hen’s laying cycle reaches dusk, she will usually not lay till the following morning. If you aren’t sure how old an egg is, you can submerge it in water. The freshest eggs will remain at the bottom of the container, while old eggs will float.
Max Sherman is a medical writer and pharmacist retired from the medical device industry. He has taught college courses on regulatory and compliance issues at Ivy Tech, Grace College and Butler University. Sherman has an unquenchable thirst for knowledge on all levels. Eclectic Science, the title of his column, touches on famed doctors and scientists, human senses, aging, various diseases, and little-known facts about many species, including their contributions to scientific research. His new book “Science Snippets” is available from Amazon and other book sellers. He can be reached by email at [email protected].
My attitude recently changed, however, when I came across an article in a recent issue of Nature journal that reported on the discovery of a giant soft-shelled egg from the Cretaceous period. A geological period that lasted from about 145 to 66 million years ago.
Previously, the largest known egg belonged to the only recently extinct elephant bird. The egg reported on in Nature was found in Antarctica and exceeds all nonavian dinosaur eggs in volume and differs from them in structure.
The fossil egg was one of the few recovered from a marine environment. It was ovoid in shape and measured 29 x 20 centimeters (cm), which is the preserved length times width. (1 inch is roughly 2.54 cm) Its shell contained roughly 15 consecutive layers of approximately equal thickness. The identity of the animal that laid the egg is unknown, but analyses of known dinosaur species suggest that the egg belonged to an individual that was at least 7 meters (almost 8 yards or 24 feet) long. It may have been a giant marine reptile. Most dinosaurs (including birds), crocodilians and turtles lay hard shelled eggs, by contrast most lizards, snakes and tuatara have a soft eggshell.
Scientists measure egg size and structure to determine the life history characteristics of vertebrates as more than two thirds of all existent amniotes (reptiles, birds and mammals) lay eggs. The structure of an egg is quite complicated, for example, the thickness of the shell may be a strategy to avoid breakage during the incubation of the largest eggs without creating a shell so thick as to inhibit hatching.
Biology
An egg in biological terms is the female sex cell or gamete. In botany, the egg is sometimes called a macrogamete. In zoology, the Latin term for egg, ovum, is frequently used to refer to a single cell, while the word egg may be applied to the entire specialized structure or capsule that consists of the ovum, its various protective membranes and any accompanying nutritive materials. Eggs are laid by female animals of many different species including birds, reptiles, amphibians, and a few mammals. Bird and reptile eggs consist of a protective eggshell, albumen and vitellus (yolk), contained within thin membranes.
Varieties
Most if not all of the eggs we consume come from chickens but the largest egg of common barnyard poultry belongs to the goose. The eggs average 3 to 4.5 inches in length with a circumference of more than 7 inches.
An average goose egg weighs 144 grams (about 5 ounces). The yolk of a goose egg is sometimes as large as a chicken egg, and you can use one goose egg for every two chicken eggs in a recipe. Turkey eggs average between 2 to 2.7 inches in length and are just under 1.5 to 2 inches wide, with an average circumference of 5 inches.
Turkey eggs vary in weight from 66 grams to more than 110 grams. Midget breeds laying the smallest eggs and heritage breeds usually producing the larger eggs. Two turkey eggs will replace three chicken eggs in a recipe.
While an ostrich may lay the world’s largest bird’s egg, it is actually the smallest in proportion to the mother – just 2% of her body weight. Chicken eggs are characterized from their size, from 1.75 to 2.5 ounces.
Chicken Eggs
In 2000, the American Heart Association (AHA) revised its dietary guidelines and gave healthy adults the green light to enjoy eggs once again.
The AHA's guidelines now allow an egg a day for healthy adults while still advising a total daily cholesterol limit of 300 mg. The confusion over eggs stems from their cholesterol content. One large egg contains 213 mg of cholesterol, accounting for two-thirds of the recommended daily limit. Along with milk, eggs contain the highest biological value (or gold standard) for protein. One egg has only 75 calories but 7 grams of high-quality protein, 5 grams of fat, and 1.6 grams of saturated fat, along with iron, vitamins, minerals, and carotenoids.
Odd Facts
Although a hen has only one exterior opening (the cloaca or vent) for egg laying and elimination, eggs are not contaminated during the laying process.
Two separate channels, the oviduct and the large intestine, open into the cloaca. As the egg nears the end of the oviduct, the intestinal opening is temporarily blocked off and the egg pass through the cloaca without contact with waste matter. Hens do not usually lay eggs in the dark, so once a hen’s laying cycle reaches dusk, she will usually not lay till the following morning. If you aren’t sure how old an egg is, you can submerge it in water. The freshest eggs will remain at the bottom of the container, while old eggs will float.
Max Sherman is a medical writer and pharmacist retired from the medical device industry. He has taught college courses on regulatory and compliance issues at Ivy Tech, Grace College and Butler University. Sherman has an unquenchable thirst for knowledge on all levels. Eclectic Science, the title of his column, touches on famed doctors and scientists, human senses, aging, various diseases, and little-known facts about many species, including their contributions to scientific research. His new book “Science Snippets” is available from Amazon and other book sellers. He can be reached by email at [email protected].
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