Biomes and Ecosystems

Question 1

Biomes

Answer 1

Broad categories of living systems

Defined mainly by climate

vary in biodiversity, productivity, and structure

Question 2

Terrestrial biomes

Answer 2

communities shaped by temperature ranges and availability of moisture (precipitation)

Question 3

Tropical Rainforests

Answer 3

Abundant rainfall; warm and hot temperatures all year

soil: thin, acidic, nutrient-poor
- 90% of nutrients in organisms

species: very high number

Types of Tropical Rainforest:
- tropical moist forests
- tropical seasonal forests

Question 4

Tropical Seasonal Rainforests

Answer 4

Distinct wet and dry seasons

Drought-deciduous trees and shrubs
- lose leaves and cease growing with low water availability

More agriculturally productive than moist forests

Highly endangered
- more humans living near

Question 5

Tropical Savannas and Grasslands

Answer 5

Savanna: grassland with sparse tree cover

Rainy season: less abundant; less dependable

Dry season: risk of fires
- plant adaptations: deep, persistent roots

Threat: grazing from livestock

Question 6

Deserts

Answer 6

Temperature: extreme hot and extreme cold

Precipitation: low and sporadic

Plant adaptations: drought-deciduous

Animal adaptations: nocturnal; concentrated excrement

Question 7

Temperate Grasslands

Answer 7

Enough rain to support grass: not enough for a forest

like plants in the savanna - deep, persisten roots
- produces thick, organic-rich soils

Main threats: agriculture and overgrazing

Question 8

Decidious forests

Answer 8

aka broad-leaf forests

Trees lose leaves in winter

Dense canopy in summer; diverse understory in spring

Greatest Threat: rapid deforestation

Question 9

Coniferous forests

Answer 9

aka evergreen forests

often occur with limited moisture

in pacific coast: known as temperature rainforests (cool, rainy, often enshrouded in fog)

pines, spruce, fir, and other species of trees

Question 10

Boreal Forests

Answer 10

Dominated by conifers with some deciduous trees
- low species diversity due to allelopathy

extreme cold and short summer
- limit growth rate of trees

Question 11

Tundra

Answer 11

Below freezing temperatures most of the year

occurs at high latitudes or on mountaintops

Low productivity
- short growing season
- frost any month of the year

Low diversity

Not directly threatened
- indirectly affected by climate change and air pollution

Question 12

Arctic Tundra

Answer 12

Extensive nights (winter) and 24-h sunshine (summer)
- important for migratory birds

Question 13

Alpine Tundra

Answer 13

on or near mountaintops; conditions and vegetation similar to arctic tundra
- alpine tundra plants: deep pigmentation, leathery leaves - protect against UV

Question 14

Marine Environments

Answer 14

Depend on tiny, free-floating phytoplankton; ocean currents and upwelling currents: transport nutrients; vertical stratification due to temperature and light decreasing with depth

Question 15

Open Ocean

Answer 15

Described by depth and proximity to the shore

relatively low productivity but have thriving communities

Features that support communities in the open ocean:
- sea mounts (undersea mountain chains and islands)
- ocean currents
- free floating mats of brown algae

Question 16

Deep-sea Thermal vents

Answer 16

Unkowng until 1977
- alvin (deep-sea submarine)

Communities based on microbes that capture chemical energy
- taken from sulfur compounds released from vents

Magma under oceanic crust provide heat to vents

Question 17

Littoral and Intertidal Communities

Answer 17

Vary with depth, light, and temperature
- like the open ocean

high productivity and density
- nutrients washing from land
- shallow, clear, warm waters supporting photosynthesis

Question 18

Coral Reefs

Answer 18

Very high productivity and biodiversity

Occurs where waters are shallow and clear
- enough for sunlight

Calcium-rich skeletons
- shelter algae and other species

Coral Polyps
- colonial animals symbiotic with photosynthetic algae

Vulnerable to human activities and ocean warming

Question 19

Seagrass beds

Answer 19

Occur in shallow, warm, sandy coastlines

support rich communities of grazers

same vulnerabilities as coral reefs

Vulnerable to human activities and ocean warming

Question 20

Tidal Pools

Answer 20

Depressions in rocky shoreline

subjected to violent wave action
- prevents plant growth and sediment accumulation

High tide: flooded
Low tide: minimal water with hot desiccating sunshine

Specialized animals and plants

Question 21

Estuaries

Answer 21

Bays where rivers empty into the sea; fresh water mixes with salt water

calm, warm, and nutrient-rich
Rivers: provide nutrients and sediments

Biologically diverse and productive; spawning for marine fish and shellfish

Question 22

Salt Marshes

Answer 22

Shallow wetlands regularly or occasionally flooded with seawater; occurs in estuaries

Question 23

Freshwater Lakes

Answer 23

Distinct Vertical zones;

Littoral zone: emergent plants create functional links between layers

Benthic zone: lowest oxygen due to little mixing; lowest light

Question 24

Wetlands

Answer 24

Shallow ecosystems; saturated or submerged part of the year

described by vegetation; adapted in saturated conditions

support rich biodiversity; essential for breeding and migratory birds

Reduce flooding; replenish groundwater supplies; filters run-off

Question 25

Swamp

Answer 25

wetlands with trees

shallow water; full sunlight penetration

high productivity

Question 26

Marsh

Answer 26

Wetlands without trees

shallow water: full sunlight penetration

high productivity

Question 27

Bog

Answer 27

Water-saturated; deep layers of peat

nutrient-poor

low productivity

Question 28

Streams and rivers

Answer 28

aka lotic environments

form when precipitation is greater than evaporation; surplus water drains from the land

constantly changing conditions and inhabitants

Question 29

Riffles

Answer 29

water runs rapidly over rocks
- well mixed and oxygenated

Question 30

Pools

Answer 30

Stretches of slowly moving current
- collect silt and organic matter

Question 31

Watershed

Answer 31

Headwaters (sources) to mouth of a drainage