Chapter 3: Biomes Flashcards
Describe Biosphere, troposphere, and Lithosphere.
Biosphere: The zones of life on earth occupied by living organisms. The biosphere is in between the Lithosphere (earth’s surface crust and upper mantel) and the troposphere (the lowest layer of the atmosphere).
What are biomes and how are they categorized?
They are large-scale biological communities shaped by the physical environment, particularly climate. Biomes are categorized by dominant plant forms, not taxonomic relationships.
What is convergence?
Evolution of similar growth forms among distantly related species in response to similar selection pressures. Ex: The physical structure of dolphins and sharks is similar even though they evolved separately. Dolphins are mammals and sharks are fish.
What percentage of the earth’s species are found in the tropical rainforest?
50%
What types of trees can be found in the tropical rainforest biome?
Broadleaved evergreen and deciduous trees.
List two other characteristics of tropical rainforests.
-No seasonal change
- annual percipitation of greater than 2000mm.
Why are tropical rainforests disappearing?
-Disappearing due to logging, conversion to pasture and cropland. about 50% of the rainforest biome has been altered.
Where are the tropical seasonal forests and savannas found?
From 10 degrees to the tropic of Capricorn and the tropic of Cancer.
What can be found in the tropical seasonal forest and savannah biome?
-Tropical dry forests
-Thorn woodland: trees have heavy thorns to protect from herbivores.
-Tropical savannas: grasses with intermixed trees and shrubs.
Describe the vegetation of tropical seasonal forests and savannahs.
Wet and dry seasons, shorter trees, deciduous in dry seasons, more grasses and shrubs.
What are some threats to the tropical seasonal forests and savannah?
Less than half of it remains. some threats are:
-Human population growth
-Converted to cropland and pasture.
Where can tropical rainforests be found?
On the equator
Where can the hot desert biome be found?
In high-pressure zones at 30 degrees N and S.
List 2 characteristics of the Desert biomes.
- High temperatures, low moisture.
-Abundance may be low but species diversity can be high.
How is the hot desert biome utilized?
Humans use it for agriculture and livestock grazing. Long-term drought and unsustainable grazing can result in desertification.
Where can temperate grassland biome be found?
Between 30-50 degrees latitude.
What are some adaptations grasses have made to survive in this environment?
-Grasses are managed by frequent fires and large herbivores such as bison.
- Grasses grow more roots than stems and leaves, to cope with dry conditions.
Soils in temperate grasses biome
-Lots of organic matter and high soil fertility.
-Most of it has been converted to agricultural land.
- Overgrazing can lead to degradation and desertification.
-Irrigation in some areas can cause salinization.
Where can temperate shrubland and woodlands be found?
Between 30 - 40 degrees N and S.
What kind of vegetation can be found in temperate shrublands and woodlands?
Evergreen shrubs and trees.
Describe the climate of temperate shrubland and woodland.
wet winters and hot dry summers.
Where can temperate deciduous forests be found?
30 - 50 degrees N on continental edges with enough rainfall for tree growth.
What kinds of trees are found in temperate deciduous forests?
Oaks, Maples and beech trees
How many species are found in temperate deciduous forests?
About 3000 plant species. Lower than tropical rainforests but still high.
Agriculture and temperate deciduous forests.
-Fertile soil and good climate for agriculture. -Agriculture has shifted to the tropics therefore deciduous forests have regrown.
-There is nutrition depletion due to agriculture.
Where can temperate evergreen forests be found?
30 - 50 degrees N and S, coastal, continental, and maritime zones.
Describe temperate evergreen forests.
-It receives high rainfall amounts and has winters.500 - 4000mm/year of rain
-Lower diversity than tropical and deciduous forests.
-Leaves tend to be acidic and soil nutrient-poor.
- High quality wood and pulp for paper. Not many old trees remain.
-Suppressed by wildfires in north america.
Where are the Boreal forests located?
50 - 65 degrees N.
