THE EARTH HAS SLOPE, GRADIENT, AND TOPOGRAPHY
In mathematics, the slope or gradient of a line is a number that describes both the direction and the steepness of the line. This can be applied to the slope of the earth.
Topography is the study of the shape and features of land surfaces.
THe structures of the land create different environments
Creatures can fill different ecological niches within a biome.
There will be differences in temperature, salinity, pH, and more.
An example of a creature that lives in a very specific environment that changes frequently is the axolotl in the Anahuac Valley, now Mexico City.
Axolotl live in brackish (semi salty) water in Xochimilco and Lake Texcoco in Mexico City, they are very endangered. They eat mollusks, worms, insect larvae, crustaceans, and some fish.
There are 17 different species of Axolotl, locally they are called achoque, they are salamanders. Salamanders are a type of amphibian, creatures that have an aquatic gill-breathing larval stage followed (typically) by a terrestrial lung-breathing adult stage.
Salamanders stay in water more but they may breathe through their skin or develop lungs. Axolotls stay in the water and don't go through metamorphosis, they develop functional lungs, but retain gills and generally use them to breathe.
There are restoration efforts that help protect the Axolotl.
They only live in one place
Their home went from being a lake, to becoming the Mexica City of Tenochtitlan in 1325, to becoming one of the biggest cities in the world after the lake was drained. There are currently still aquifers under Mexico City and the people drink this aquifer water, so the city is sinking.
MEXICO CITY DURING AZTEC (Mexica) TIMES, YEARS 1324-1430
It was a tricky place to grow food:
Lake Chalco and Lake Xochimilco to the south were freshwater lakes, lakes to the north, Tetzcoco, Xaltocan and Zumpango, were salty.
Axolotl adapted to changing levels of salinity, when floods moved water from salty areas to freshwater areas, many plants and animals would die. There are also aquifers, underground water ways, that feed the lakes.
To overcome the problems of drinking water, Aztec (Mexica or Tenochca Mexica) engineers built a system of dams to separate the salty waters of the lake from the rain water of the effluents.
Aztec (Mexica) communities grew food on Chinampas, strips of land that were made from the fertile soil from the bottom of the lake. They were artificial islands.
People in this region spoke Nahuatl, it is still spoken by about 1.7 million people today. The people in this region identified as Mexica or Tenochca Mexica, not as Aztec.
Spanish COnquerors drained the lakes
When Spanish Conquistadors went to what is now Mexico City, they destroyed as much of the city as they could and drained the lakes to build a new city on top of the existing city.
This video shows us why and how the region is slowly sinking:
Efforts to protect Axolotl
This conservation effort involves making cough syrup with them :(, you win some, you lose some. Axolotls are very important in medicine, we will learn more about that soon.
Another threat to rivers and lakes is eutrophication, when fertilizers are washed off the land and into the bodies of water.
When there are too many nutrients in a lake or other body of water, generally because of runoff from the land. Excess nutrients cause a dense growth of plant life and death of animal life from lack of oxygen.
The area where the axolotl lives is their habitat, the habitat is part of a biome
A biome includes many habitats and many ecosystems.
A biome may be an ocean, grassland, a forest, a tundra, rainforest, desert.
The Marine Biome covers about 70% of the Earth's surface and is home to more than 230 thousand known species. Marine plants provide over half of the oxygen on Earth. There are separate biomes within the ocean based on depth, temperature, and biodiversity. A coral reef is a biome. Within the coral reef there are different habitats and niches.
Rivers streams, ponds and lakes, and wetlands are fresh water biomes.
Polar regions have tundras, there are less plants, animals need to get food from the ocean or hunt other creatures.
Forests may be full of evergreen trees in colder areas.
Tropical Rainforests get more moisture and humidity, they are close to the equator and are warm, full of life. Important producers of oxygen and many medicinal plants have been discovered there.
A savannah or grassland has low growing plants like grass and flowers.
Deserts are dry, may be hot or cold, very little rain, may drop to below freezing at night and be very hot during the day. Have cacti, grasses, shrubs, some trees.
People are reflecting on the lack of regard for the environment and are speaking up
Greta Thunberg is a Swedish environmental activist who is internationally known for challenging world leaders to take immediate action against climate change.
She was diagnosed with Asperger syndrome/ Autism, obsessive–compulsive disorder (OCD), and selective mutism.
In one of her first speeches demanding climate action, Thunberg described the selective mutism aspect of her condition as meaning she "only speaks when necessary." She is now 18 years old.
Author: Jazmin Gannon
A place to grow