How did glaciation affect the Great Lakes?
The massive weight and movement of this glacier gouged out the earth to form the lake basins. About 20,000 years ago, the climate warmed and the ice sheet retreated. Water from the melting glacier filled the basins , forming the Great Lakes.
Did the Great Lakes used to be an ocean?
Thousands of years ago, the melting mile-thick glaciers of the Wisconsin Ice Age left the North American continent a magnificent gift: five fantastic freshwater seas collectively known today as the Great Lakes — Lake Superior, Lake Huron, Lake Michigan, Lake Erie and Lake Ontario.
How did fish get into the Great Lakes?
Just as an island may once have been connected by a land bridge, so lakes may originally have been part of river systems that dried up. When waterbirds come to lakes to feed, fish eggs might get stuck to their feathers, hitching a ride to a new home.
How does the water flow through the Great Lakes?
Water flows from Lake Superior and Lake Michigan into Lake Huron; then through the Detroit River into Lake Erie; then through Niagara Falls into Lake Ontario; and then through the Saint Lawrence River to the Atlantic Ocean. Water also drains from the Chicago River on the south.
Why did the glaciers melt in the ice age?
When less sunlight reaches the northern latitudes, temperatures drop and more water freezes into ice, starting an ice age. When more sunlight reaches the northern latitudes, temperatures rise, ice sheets melt, and the ice age ends. To find out more about Earth’s climate in the past, scientists study ice cores.
How are glaciers formed in lakes?
Glacial lakes typically form at the foot of a glacier. As glaciers move and flow, they erode the soil and sediment around them, leaving depressions and grooves on the land. Meltwater from the glacier fills up the hole, making a lake. The moraines often act as barriers, causing meltwater to pool and form a lake.
Was Lake Superior formed by glaciers?
it was cold enough for glaciers to form in North America. The shorelines of modern Lake Superior started to develop almost 10,000 years (B.P.) 9,500 Years Ago, The glaciers towered several kilometres above the ground, and the massive weight of the ice pushed the earth’s crust down.
How did the Great Lakes form quizlet?
How were the Great Lakes formed? Glaciers cut out deep depressions and pushed ahead rock and soil. When they melted, the rock and soil piled up and blocked drainage. Then water eventually filled the lakes.
How do fish get pregnant?
In most cases, the female drops eggs in the water which are immediately fertilized by sperm from the male. Another way is for fertilization to occur within the females body before she drops them into the water. With the third and final method, the female retains the eggs within her body and the young are born alive.
How did fish get into glacial lakes?
The answer is that (assuming they were not introduced by humans) the species date from the glacial period when the lakes were submerged. When the glaciers retreated (and/or the land rebounded) the populations were trapped in the lakes. This has been proven through genetic analysis of land-locked species.
Who controls Great Lakes water?
The water in the Great Lakes is owned by the general public according to the Public Trust Doctrine. The Public Trust Doctrine is an international legal theory – it applies in both Canada and the United States, so it applies to the entirety of the Great Lakes.
What river flows into the Great Lakes?
Among the waterways linking the lakes are the St. Marys River, which flows from Lake Superior to Lake Huron; the Niagara River, connecting Lake Erie to Lake Ontario; and the narrow Straits of Mackinac, joining Lake Michigan and Lake Huron (hydrologically, the two lakes are considered a single body of water).