Age Structure and Human Population Growth

Question 1

Lakes biome

Answer 1

Physical and Chemical Properties:
-variable sizes
-Oligotrophic lakes are nutrient poor and O2 rich w/ low organic content in sediments
-Eutotrophic lakes are nutrient rich high in organic content in sediments; O2 is periodically depleted in deeper layers due to high rates of decomposition

Biodiversity
-rooted and floating aquatic plants live in the shallow areas close to shore
-phytoplankton and zooplankton inhabit the open water
-invertebrates live in the benthic zone
-fishes live in all areas w/ sufficient oxygen

Question 2

Wetlands biome

Answer 2

Physical and Chemical Properties:
-inundated by water at least some of the time
-develop in shallow basins, along flooded river banks, or on the coasts of large lakes and seas
-rapid organic production and decomposition periodically deplete dissolved oxygen

Biodiversity
-plants adapted to water-saturated soil
-plants include lilies, cattails, sedges, etc.
-woody plants dominate swamps, sphagnum, mosses dominate bogs
-home to diverse invertebrates and birds
-wetlands are among the most productive biomes

Question 3

Streams and rivers biome

Answer 3

Physical and Chemical Properties:
-the most prominent physical characteristic of streams and rivers is current
-headwater streams are usually cold, clear, swift, and turbulent; downstream rivers are warm and turbid
-streams and rivers are generally O2 rich, but organic enrichment can deplete O2 downstream

Biodiversity
-headwater streams may be rich in phytoplankton or rooted aquatic plants
-a diversity of fishes and invertebrates inhabit unpolluted rivers and streams

Question 4

Estuary biome

Answer 4

Physical and Chemical Properties:
-nutrient rich and productive transition zone between a river and the sea
-salinity varies spatially-from nearly fresh water to that of seawater-and w/ the changing tides

Biodiversity:
-saltmarsh grasses and algae are the major producers
-invertebrates, fish, waterfowl, and marine mammals are abundant

Question 5

Intertidal biome

Answer 5

Physical and Chemical Properties
-periodically submerged and exposed by the tides
-upper intertidal zones experience longer exposure to air and greater variation in temp. and salinity
-oxygen and nutrient levels are generally high in intertidal zones

Biodiversity:
-unprotected sandy and rocky intertidal zones support attached algae; protected sandy zones support seagrass and algae
-in rocky zones, many animals have structural adaptations for attaching to the hard subtrate
-in sandy zones, worms, clams, and crustaceans bury themselves in sand
-other animals include sponges, sea anemones, echinoderms, and small fishes

Question 6

Oceanic Pelagic Zone biome

Answer 6

Physical and Chemical Properties:
-an expanse of open water covering approx. 70% of Earth’s surface
-oxygen levels are generally high, but nutrient concentrations are lower than coastal waters

Biodiversity:
-phytoplankton and zooplankton are the dominant organisms
-phytoplankton in this zone account for about half of the photosynthesis on Earth
-fish, squid, turtles, and marine mammals are common

Question 7

Coral reef biome

Answer 7

Physical and Chemical Properties:
-formed from the calcium carbonate skeletons of corals
-shallow reef-building corals live in warm, clear water; deep-sea corals live at depths of 200-1,500 m
-corals require high oxygen concentrations and a solid substrate for attachment

Biodiversity:
-corals form a mutualistic relationship w/ unicellular algae, which provide them w/ organic molecules
-in addition to corals, other invertebrates and fish are also exceptionally diverse

Question 8

Marine Benthic Zone biome

Answer 8

Physical and Chemical Properties:
-consists of the seafloor below the surface waters of the coastal zone and the offshore pelagic zone
-oxygen is typically abundant enough to support diverse animal life
-very deep benthic zones are cold (about 3 degrees Celsius) and have very high-water pressure

Biodiversity:
-photosynthetic organisms, seaweeds and filamentous algae, are restricted to shallow areas
-chemoautotrophic prokaryotes are the food produces surrounding deep hydrothermal vents
-giant tube worms, echinoderms, and arthropods live around the hydrothermal vents

Question 9

The unregulated growths are logistic growth and exponential growth. T o F?

Answer 9

False

Question 10

Demographic transition

Answer 10

in a stable population, a shift from high birth and high death rates to low birth and low death rates

Question 11

Age structure

Answer 11

relative number of individuals of each age in a population; expressed in pyramids; helps predict a population’s growth trends and illuminate social conditions and help us plan for the future

Question 12

Ecological footprint

Answer 12

the aggregate land and water area required by a person, city, or nation to reproduce all of the resources it consumes and to absorb all of the waste it generates; USA has one of the highest

Question 13

Global hectare

Answer 13

hectare of land or water w/ a productivity equal to the average of all biologically productive areas on Earth (1hectare = 2.47 acres)

Question 14

Human population growth

Answer 14

it is no longer growing exponentially but is still increasing rapidly; our carrying capacity could be limited by food, space, nonrenewable resources, or buildup of waste; unlike other organisms, we can regulate our population growth through social changes

Question 15

Why is the red curve decreasing and the blue one increasing?

Answer 15

Because the rate of growth is decreasing (red curve), but the population size is still increasing (curve)