Showing posts with label settlement. Show all posts
Showing posts with label settlement. Show all posts

Genetic Resistance by Tasmanian Devils to Facial Disease (DFTD) - Biology

Biological research shows genetic resistance to Tasmanian devil disease.
The Tasmanian devil is an animal unique to Australia. It Once resided all over the continent. Perhaps is was easy for Aboriginals to catch for food. It cannot run very fast. It could just have died out due to a warming of the country. Tasmania is its only natural home today.
Tasmanian devil facial tumor disease (DFTD
Their raucous cries led to them being named devils by European settlers. They are violent to each other though attacks on humans are virtually non-existent. Scavenging for food is their number one priority.

A facial disease began in the species in 1996. It was unusual in that it is the only known cancer transmitted from animal to animal. Tasmanian devil numbers fell by 80 per cent in twenty years due to Tasmanian devil facial tumor disease (DFTD).

Extinction was predicted. However, it was noticed that some animals survived without getting the disease. Genes were examined and these devils had five genes not present in their brothers who succumbed. This shows that all animals currently living are unlike their ancestors who dominated even a hundred years ago.
 
tasmanian, devil, disease, facial, european, settlement, dftd, extinction, survice, dnd, genes, resistance
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Pioneers Had More Children

People living in different places "breed" at different rates. Reasons put forward are level of income, education of women and access to contraceptives. Family size has also changed at various places in history. The adventurous ones who ventured far and wide had more children than those who remained in established urban centers. This is particularly the case for British and French settlers in North America.

Resources were more plentiful in new unsettled regions. For example, buffalo and native animals could easily be shot and eaten on the spot. New settlers were also healthier, being active for most of their lives. An examination of Canadian records since 1608 shows that couples on the outer edge of expansion had 20 per cent more children than those remaining in established regions. They also married younger. The pioneer contribution to the gene pool was four time greater than those who settled in populated areas. Church records were the main data source. If the number of illegitimate children were known the gene pool contribution could have been even higher.

Human growth in new expanses of virgin land is consistent with plant and animals. Weeds grow vigorously on new accessible land. Larger plants soon take hold as do small animals. The small animals also attract larger animals. Over time as life becomes denser reproduction rates decline. Saying that pioneers in the West grew like weeds is close to the truth. The spread of Mankind across the globe is no accident. It seems to be an evolutionary imperative.
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History
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