It usually is some sort of physical barrier like an large space between islands.
The population has evolved into two separate species if the species in question no longer interbreed.
The proper scientific explanation to a red tide is that they are caused by large populations of phytoplankton and they emit a lot of toxins as waste. It is a very well explained phenomenon.
A major factor in the growth of the population of the English colonies was the number of settlers that immigrated to the colonies. They caused the populations to gradually grow as they settled in these colonies.
Leper says that Gene was the one who caused Phineas to be hurt.
When genes are exchanged due to the mixing of populations, the result is gene flow. Genetic drift, along with natural selection, mutation, and migration, is one of the basic mechanisms of evolution.
They used the same materials on other patients.
Robert Koch
Acid Rain
the Himalayas and the Gobi Desert.
The geographical setting of Greece.
Pollution mainly.
Slaves formed families and had children.
only two people survived this
Influenza. It is caused by this new strain of virus that was isolated in Mexico and is now known to be the underlying organism that caused the 2009 pandemic.
Darwin wondered if the finches on the Galapagos Islands were an ancester to the mainland finches. It turns out they were, one finch went to the island and its decsandants spead across the island. Geographic isolation caused the gene pools to become isolated and each population adapted to a particular habitat on the Galapagos Islands. Over time all the populations became genotypically different that they do not interbreed. Mating finches look for the beak shape.
All tornadoes are bad. Most isolated tornadoes are weak, rated F0 or F1 and rarely kill. A few isolated tornadoes have relieved ratings of F3 or highger, howver, which is a very strong tornado
Isolated manufacturing issue' caused wind turbines to break in Illinois.
the thing that caused people to become interested in Alaska was the gold rush.