What are we learning? Why are we learning this?
content, procedures, skills
Tier II: High frequency words used across content areas. Key to understanding directions, understanding relationships, and for making inferences.
Tier III: Low frequency, domain specific terms
Building on what we already know
What vocabulary & concepts were learned in earlier grades?
Make connections to prior lessons from this year.
This is where we start building from.
A biome is a large area on Earth defined by
(a) average temperature, over the course of a year
(b) average rainfall, over the course of a year
(c) the types of animals and plants living there.
Tropical Rainforest (interior Brazil)
Temperate Rainforest (southern coast of Alaska)
So have you been to the temperate rainforest in Alaska?
A rainforest in Alaska? Surely you must be joking.
I’m not joking, and stop calling me Shirley
– with apologies to Zucker, Abrahams and Zucker
The Tongass National Forest in southeastern Alaska is the largest national forest in the United States. 17 million acres (69,000 km2). Most of its area is part of the temperate rain forest … it is home to many species of endangered and rare flora and fauna. The Tongass, which is managed by the United States Forest Service, encompasses islands of the Alexander Archipelago, fjords and glaciers, and peaks of the Coast Mountains.
Tropical dry forest
In a desert, what is under all of the sand? On Reddit, Phosphenes offers us this enlightening answer.
the Sahara, contrary to popular belief, is mostly not covered in sand dunes. Here’s a map of all the dune fields (in yellow) in the Sahara. Most of the Sahara looks something like this– a rock-strewn sandy soil with a hard crust (“desert pavement”), like what you see in the Mars rover photos but with scattered bushes.
The dunes covered places that look like that, so imagine a rocky soil a few meters thick at the bottom of the dunes. Then the groundwater level is usually somewhere above the old ground level, so imagine that it’s soaking wet and muddy.
That’s what it’s like down there. The dunes are not like glaciers- they don’t rub rock formations smooth once they’re buried. They mostly preserve it whole. (For an extreme example of this, see the camel thorn trees of Namibia which were buried centuries ago and only recently uncovered as the dune kept migrating.)
Another thing to consider is where all that sand came from. You get sand dunes when the environment is producing more new sand grains faster than it can stabilize them into rock.
The Sahara has so many dune fields because when the climate was wetter about 6000-10000 years ago, there were massive lakes covering what is now desert. When these lakes dried up, their sandy bottoms provided an ample source of sand to make dunes (and an ample source of nutrients in the form of wind blown dust to feed the Amazon rainforest). Here’s a map (snipped from this paper) of all the huge lakes and alluvial fans (in blue and gray) that used to cover the Sahara.
Notice how many of them are in the same parts of the desert that now have dune fields in that earlier image? In many places, the current dunes are directly over the old lake bed, so the bottom of the dunes is exactly what you would imagine a dried up lake to be like. See this radar image from an earlier askscience question. The top of the gray bar is the top of the dunes, and the red line is the bottom. It’s so flat because it’s an old lake bed. There probably aren’t mountain ranges or other huge topographical features buried under the sand.
Temperate woodland and shrubland
Temperate forest (America’s northeast)
Northwestern coniferous forest
Biomes of North and South America (can you find the rainforest in Alaska?)
Chapters from textbooks
Biomes – Holt Environmental Science
Tropical rainforest, Temperate rain forests, Temperate deciduous forests, Taiga (northern coniferous forests)
Savannahs (Grasslands), Chaparral (temperate woodland biome), Desert and Tundra
Students should know that: The world contains a wide diversity of physical conditions, which creates a wide variety of environments: freshwater, marine, forest, desert, grassland, mountain, and others. In any particular environment, the growth and survival of organisms depend on the physical conditions. 5D/M1b*
By the end of grade 8. Biodiversity is the wide range of existing life forms that have adapted to the variety of conditions on Earth, from terrestrial to marine ecosystems. Biodiversity includes genetic variation within a species, in addition to species variation in different habitats and ecosystem types (e.g., forests, grasslands, wetlands). Changes in biodiversity can influence humans’ resources, such as food, energy, and medicines, as well as ecosystem services that humans rely on—for example, water purification and recycling.
By the end of grade 12. Biodiversity is increased by the formation of new species (speciation) and decreased by the loss of species (extinction). Biological extinction, being irreversible, is a critical factor in reducing the planet’s natural capital.
LS4.D: Biodiversity and Humans
There are many different kinds of living things in any area, and they exist in different places on land and in water. (2-LS4-1)