1. Biology 1
Chapter 21
Ecosystems

2. Do Now
Which of the following shows the organizational level of a biome from the broadest category to the most specific category?
A. biome population  community  ecosystem  organism
B. biome  ecosystem  community  population  organism
C. biome  community  ecosystem  population  organism
D. biome  ecosystem  population  community  organism

3. Biomes
Biomes-large climatic regions that contain a number of smaller but related ecosystems within them.
May exist in more than one location on Earth, but each location has a similar climate.

4. Terrestrial Biomes-Tundra
Tundra-cold and largely treeless
Permafrost-permanently frozen layer of soil under the surface
Small slow growing plants like grass, moss
Short growing season
Few nutrients in soil due to low temperatures that hinder decay

5. Tropical Forest Tropical forest-occur near the equator
Stable temperatures
Abundant rainfall
Two seasons: One wet & one dry
Have the highest species richness of all biomes
Tropical dry forest-have long dry seasons during which the trees lose their leaves
Tropical rain forest-characterized by long wet seasons and tall trees and plants that grow year-round.

6. Competition for light is intense in a tropical rain forest.
Canopy-a continuous layer of treetops which shades the forest floor.
Jungle-dense growth found along riverbanks and in disrupted areas where sunlight can reach the forest floor.
Epiphytes-small plants that live on the branches of tall trees; produce their own food
Ex. Mosses, orchids, and bromeliads

7. Temperate Forest
Occur in eastern North America, western and central Europe, and northeastern Asia
Distinct seasons
Moderate climate
Characterized by the type of tree that is most common
Two Types: Deciduous and Coniferous

8. Temperate Deciduous Forest-lose all of their leaves in the fall and regrow them in the spring.
Have pronounced precipitation with precipitation unevenly distributed through the years.
Trees have broad, thin leaves with a large surface area
Large areas have been cut down for timber or cleared for human inhabitation.

9. Taiga-Forested biome dominated by coniferous trees
Also known as the boreal forest or temperate coniferous forest
Long winter with snow covers and insulates the ground, protecting tree roots.
Plants are adapted for long, cold winters, short summers, and nutrient-poor soil.
Waxy, needle-shaped leaves remain on the tree all winter long and adapt against water loss.

10. Grasslands Dominated by a variety of grasses
Known by different names in different parts of the world
North America-Prairies
Asia-Steppes
South America-Pampas
Africa-Veldts

11. Temperate Grasslands-usually form in the interior of continents with rainfall patterns that make these areas too dry to support trees.
Have rich, fertile soil
Support large herds of grazing animals
Can survive repeated grazing and fires because the actively growing part of the plant is at or below the ground.
Many have been transformed into farmland

12. Savanna-tropical or temperate grasslands that have scattered deciduous trees and shrubs
Have more rainfall than deserts
Have alternating wet and dry seasons
Some trees shed their leaves during the dry season
Support large numbers of herbivores and carnivores

13. Chaparral-dominated by dense, spiny shrubs and scattered clumps of coniferous trees
Mild, rainy winters and hot, dry summers with periodic fires
Found mainly in coastal settings.

14. Desert-areas that receive an average of less than 10 inches of rainfall per year
Cold desert-hot in summer but cold in winter
Great Basin and Gobi Desert
Vegetation is sparse and consists of plants that have waxy coatings
Animals avoid heat of the day by hiding or burrowing

15. Do Now
Which choice below lists the biomes in order from lowest precipitation amounts to highest precipitation amounts?
A. desert, temperate deciduous forest, grasslands, tropical rainforest
B. grasslands, desert, tropical rainforest, temperate deciduous forest
C. desert, grasslands, temperate deciduous forest, tropical rainforest
D. grasslands, desert, temperate deciduous forest, tropical rainforest
Answer: C

16. Do Now
A pod of dolphins hunting and feeding on a school of fish is an example of
A. a community interaction.
B. a biome interaction.
C. a population interaction.
D. an ecosystem interaction.
Answer: A

17. Aquatic Ecosystems: Ocean Zones
Photic Zone-the part of the ocean that receives sunlight
Aphotic Zone-the zone where sunlight cannot penetrate
Zones relative to the ocean’s edges:
Intertidal
Neritic
Zones relative to the open ocean:
Pelagic-not near coast
Benthic-sea floor

18. Intertidal Zone-the area of shoreline that is twice daily covered by water during high tide and exposed to air during low tide.

19. Coral reefs-built by coral animals over long periods of time
Neritic Zone-Extends from the intertidal zone over the continental shelf and to relatively shallow water
The most productive zone in the ocean.
Upwelling-strong currents that carry nutrients from the ocean bottom and mix them with nutrients contained in runoff from land.
Plankton-communities of small organisms that drift with the ocean currents
Coral reefs-built by coral animals over long periods of time

20. Oceanic Zone-encompasses the deepest parts of the ocean
About half of the photosynthesis that occurs on Earth takes place in the oceanic zone

21. Estuary-occurs where freshwater rivers and streams flow into the sea
Ex. Bay, mud flat, mangrove swamp, salt marsh
Shallow water receives light, & rivers deposit large amounts of minerals
Contain Sphagnum moss

22. Freshwater Zones Lakes and ponds are divided into two categories:
Eutrophic lakes-rich in organic matter and vegetation, so the waters are relatively murky.
Oligotrophic lakes-contain little organic matter and the bottom is usually sandy or rocky

23. River/stream-body of freshwater that flows down a gradient toward its mouth.

24. Freshwater wetlands-areas of land that are covered with fresh water for at least part of each year.
Most productive freshwater ecosystem
Important stopovers for migratory birds
Provide protection for spawning organisms.
Act as filters to clean pollutants out of the water
Act as flood control

25. Two types of wetlands: Marshes-contain non-woody plants
Swamps-contain woody plants

26. Do Now
Which choice below lists the biomes in order from lowest average temperatures to highest average temperatures?
A. taiga, tropical rainforest, grasslands
B. taiga, temperate deciduous forest, savanna
C. tundra, grasslands, taiga
D. tundra, savanna, temperate deciduous forest
Answer: B