THE ORIGIN OF MAMMALS

MAMMALS have colonised almost every part of our planet, both on land and in water. They range in size from the pigmy shrew at 80 mm. (3.25 ins) long, to the blue whale, 33 metres (109 feet) in length. There are three sub-classes of mammals, the monotremes (egg-laying mammals), the marsupials and the placentals. But what of their origins? It is popularly believed that mammals evolved from reptiles, but there are many problems with this theory.

DIFFERENCES

Although their skeletal structures show many similarities, there are actually significant differences between reptiles and mammals. Many of these differences, being in the soft parts of the anatomy, would not be preserved in the fossil record. For example, all mammals possess a diaphragm, reptiles don't. What did the mammalian diaphragm evolve from? All mammals have an essential organ in the middle ear — the Organ of Corti, which consists of 3,000 adjacent arches forming a tunnel. Reptiles don't have this organ or, anything like it, so how did mammals come by it? Another feature unique to mammals are the mammary glands, which provide milk for the young. From what did they develop? Some have suggested sweat glands, but sweat is a waste product, whereas milk is full of rich nourishment. All mammals, including the monotremes, feed their young on milk, which is essential for their survival.

EAR AND JAW PROBLEMS

All reptiles, living and fossil, have several jaw bones and only one ear bone, whereas all mammals, living and fossil, have only one jaw bone and three ear bones. According to evolutionists, during the transition from reptile to mammal, two of the jaw bones disengaged themselves from the jaw and gradually moved to the ear, there connecting with the existing bone to form the typical mammalian ear. The fossil record does not reveal this kind of transition. Indeed, it is difficult to imagine bones migrating during the course of evolution, and one wonders how any creature undergoing this kind of transition could either eat or hear properly.

'MAMMAL-LIKE REPTILES'

Evolutionists claim that a group of extinct animals known as 'mammal-like reptiles' were transitional, particularly two specimens, Morganucodon and Kuehneotherium, which are about four inches long. But even these had the normal reptilian bone arrangement in both jaws and ears.¹ They may have been 'mammal-like', but they were reptiles nonetheless. Another specimen, Dimetrodon, had a large sail-like structure on its back. There is no evidence that it evolved from, or into, anything.

According to evolutionary dating, the mammal-like reptiles appeared in the Permian period '280 million' years ago, at the same time as true reptiles. It had been believed that they became extinct in the Jurassic, 160 million years ago, but recently, fossil remains of a mammal-like reptile were found in the upper Palaeocene.² So, on the evolutionary timescale, they co-existed with their supposed mammalian descendants for 130 million years — 100 million years longer than previously thought! As no fossils have been found in rocks of the intervening period, we suggest that those 100 million years never existed.

ORIGIN OF SUB-CLASSES

The three sub-classes of mammal appear suddenly in the fossil record.

The three sub-classes of mammal, monotremes, marsupials and placentals, all appear in the fossil record abruptly. Evolutionist Roger Lewin has written: 'The [evolutionary] transition to the first mammal, which probably happened in just one or, at most, two lineages, is still an enigma.'³ Although the monotremes (egg-laying mammals) such as the spiny anteater and platypus are often described as 'primitive', there is no evidence to link them with any reptilian ancestor. David Attenborough wrote: 'We have no hard evidence to indicate which fossil reptiles were their ancestors.'⁴

Marsupials or pouched mammals are now confined to Australasia (with one exception, the opossums of South America), but their fossils have been found in a number of locations. However, the oldest fossils are clearly marsupial. The placental mammals are the most diverse, consisting of 18 separate orders, but each of these is distinct from its earliest appearance in the fossil record. Half a century ago, George Gaylord Simpson wrote, 'The earliest and most primitive known members of every order already have the basic ordinal characters, and in no case is an approximately continuous sequence from one order to another known. In most cases the break is so sharp and the gap so large that the origin of the order is speculative and much disputed.'⁵

When we consider the vast differences between whales and giraffes, elephants and bats, it seems incredible to believe that they could all have evolved from a shrew-like creature over a period of 200 million years without leaving a trace of fossil evidence. The facts, however, are completely compatible with the Bible record of creation. 'God made the wild animals according to their kinds, and all the creatures that move along the ground according to their kinds. And God saw that it was good.' ( Genesis 1)

Placental mammals give birth to five young.

REFERENCES:

1. For full discussion, see Evolution: The Fossil Still say No! by Dr. Duane Gish (Master Books, 1985) pp. 88-103.
2. 'Post-Jurassic mammal-like reptiles from the Palaeocene', Nature 358, pp. 233-235.
3. Bones of mammals' ancestors fleshed out', Science Vol. 212, 28th June 1981, p. 1492.
4. Life on Earth, William Collins 1979, p. 205.
5. Tempo and Mode in Evolution, Columbia University Press, New York, 1944, p. 105.

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