LS 9-11 Notes

LS 9-11 Notes

LS 9

  • The living organisms within a specific area and their physical environment define an ecosystem.
  • Biomes are made up of a collection of similar ecosystems
  • Characteristics of land, marine, & freshwater ecosystems vary w/ respect to biotic and abiotic factors.
  • The major terrestrial ecosystems are classified into units called biomes — large regions characterized by certain conditions, including a range of climate and ecological communities adapted to those conditions.
  • Organisms possess adaptations to both biotic and abiotic factors in their ecosystem that increase their chance of survival.
  • The main biomes are:

Marine-any body of salt water

Freshwater-lakes, rivers, ponds, and streams

Desert-0-25 cm of rain a year, plant adaptations-waxy outside, shallow roots, animal adaptations-nocturnal, tough skin, burrow underground

Grassland-plants have deep roots, lots of crops grown here, little amount of trees, 25-100 cm of rain, transitional biome, other names are: veldt, savannah, pampas, steppe, prairie, and bread basket

Coniferous Forest-(boreal) there is a triangle shape to trees and a waxy coat, acidic soil, animal adaptations include- migration and hibernation, thick fur or hollow fur, long legs, 150 frost free days a year

Tundra-low growing plants with shallow roots, no trees, and the permafrost is 2000ft deep, 0-25 cm of rainfall a year, least biodiverse, same adaptations as boreal

Deciduous-our biome, plants adaptations-trees lose leaves, go dormant for 6 months, rich soil, 80-200 cm of rainfall a year, animal adaptations-ectothermic to survive as well as migration and hibernation

Tropical Rainforest-most biodiverse biome, soil not nutrient rich, 1% of sunlight reaches forest floor, plants get nutrients from dead and decaying logs, also some get nutrients from the air and do not have roots in soil

General Biome Notes:

  1. There are 3 climate zones-tropical (at equator), polar (north and south poles) and temperate (biggest zone-between the equator and poles)
  2. Climate, geography and elevation determine biomes
  3. A transitional biome means that if it received more or less rainfall, then it would become a different biome.
  4. There are temperate and tropical deciduous forests and the same for tropical
  5. There are 4 levels of tree heights- emergent (top), canopy, understory, and floor

LS 10

  • Organisms may exist as members of a population; populations interact with other populations in a community; and communities together with the physical environment form ecosystems.
  • Changes that affect organisms over time may be daily, seasonal, or long term.
  • Plants may respond to light by growing toward it or away from it, a behavior known as phototropism.
  • Animals may respond to cold conditions with a period of lowered metabolism, a behavior known as hibernation.
  • Organisms may respond to adverse conditions with a period of lowered or suspended metabolism, a behavior known as dormancy. Plants can go dormant.
  • A variety of environmental factors may cause the size of a population to increase or decrease.
  • Long-term changes may affect entire communities and ecosystems. Such large-scale changes include the addition of excess nutrients to the system (eutrophication), which alters environmental balance; dramatic changes in climate; & catastrophic events, such as fire, drought, flood, and earthquakes.


LS 11

  • Ecosystems are dynamic systems. Humans are a natural part of the ecosystem. Humans use the ecosystem to meet their basic needs, such as to obtain food.
  • Human interaction can directly alter habitat size, the quality of available resources in a habitat, & the structure of habitat components. Such interactions can be + and/or -.
  • Human input can disturb the balance of populations that occur in a stable ecosystem. These disturbances may lead to a decrease or increase in a population. Since populations in an ecosystem are interdependent, these disturbances have a ripple effect throughout the ecosystem.
  • The interaction of humans w/the dynamic ecosystem may lead to issues of concern for continued ecosystem health in areas such as water supply, air quality, energy production, & waste management.