ES101 Lecture Notes - Lecture 19: Primary Production, Tropical Rainforest

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byzantiumcaribou961

19 Feb 2018

School

WLU

Department

Environmental Studies

Course

ES101

Professor

Doctor Edmund Okoree

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Document Summary

The productivity of an ecosystem is an important measure of the available amount of energy for each trophic level. In simple terms the primary productivity of earth is a measure of how much food is created by plants and the sun for consumers. More specifically, we can calculate the net primary productivity as the amount of energy produced by photosynthesis minus the amount of energy loss in maintaining the plant. This is also a measure of the energy used in respiration. Therefore, net primary productivity (npp) can be expressed as. Npp can also be expressed as how much biomass (plant material) is produced over a period of time. Your textbook provides a chart of the relative measures of npp for different ecosystems. Which ecosystems are the greatest producers of npp: swamps and marshes, tropical rain forest, estuaries. Which are the lowest: extreme desert, desert scrub, tundra.

Related Questions

11. As energy flows through the food web in an ecosystem, the amount of energy that is transferred from one trophic level to the next trophic level increases. stays the same. decreases. may increase or decrease, depending upon the system.

12. Autotrophs are organisms that obtain energy by breaking down tissues of organisms that have died. harness external energy sources to produce complex chemical compounds. depend directly on primary producers for their energy and nutrients. eat other autotrophs to obtain energy.

13. Which of the following gives the correct order for energy flow through an ecosystem? primary producers â secondary producers â tertiary producers primary consumers â primary producers â secondary producers secondary consumers â primary consumers â primary producers primary producers â primary consumers â secondary consumers

14. Which one of the following aspects of plant biology is not directly involved in maintaining an adequate supply of water for the entire plant? phloem roots xylem transpiration pull

15. Which structure(s) do most plants use to acquire the energy that they need for cellular processes? the roots the leaves the stem

1. You are an ecologist interested in energetics of ecologicalsystems. You begin your current research program with a study ofprimary productivity of corn plants growing in a field in Iowaduring mid-summer. At noon on a sunny day, you enclose a singleleaf (still attached to the plant) in a transparent chamber. Thechamber is connected to a measurement device called an infrared gasanalyzer, which is capable of measuring minute changes in theconcentration of carbon dioxide (CO2) of the atmosphere within thechamber. The chamber is also maintained at a constant 30Â°C (same asthe outside air temperature) during your observations. You firstexpose the corn leaf to full sunlight and observe that CO2 is beingdepleted by the leaf from the chamber at a rate of 18 mg CO2 per100 cm2 leaf area per hour. You then cover the chamber withaluminum foil to exclude all light and observe that CO2 is beingreleased by the leaf into the chamber at a rate of 3 mg CO2 per 100cm2 leaf area per hour.

Questions

What is the rate of net primary productivity for this leafduring the measurement period (In mg CO2 per 100 cm2 leaf area perhour)? What is the rate of respiration for this leaf (same units asabove)? What is the rate of gross primary productivityfor this leaf (same units as above)? At this site, cornis planted at a density that results in 75% of the surface beingcovered by leaves. What is the total net primary productivity forone hectare of this corn field (in g C per hectare per year)?Assume that day length averages 12 hours per day over the course ofa 180 day growing season and that your measurement isrepresentative of the NPP for the entire growing season. Show yourcalculations.

The total amount of energy invested in the production of living biomass in a community is that community's

Select one:

a. gross primary productivity

b. net primary productivity

c. gross photosynthetic efficiency

d. net photosynthetic efficiency

Which of the following factors accounts for the largest number of documented extinctions that have occurred in the last 1,000 years?

Select one:

a. Deforestation

b. Habitat fragmentation

c. Pollution

d. Invasive species

In terrestrial ecosystems, the greatest current cause of species endangerment is

Select one:

a. invasive species

b. habitat loss

c. overharvesting

d. pollution

Carbon dioxide has a warming effect on the earth's atmosphere. This is because it absorbs

Select one:

a. ultraviolet radiation coming from the earth's surface

b. visible light coming directly from the sun

c. ultaviolet radiation coming from the sun

d. infrared radiation coming from the earth's surface

The overall productivity of the open ocean has declined as a result of global warming.This is believed to be because

Select one:

a. ocean stratification has intensified

b. cloud cover has increased, reducing sunlight over the ocean

c. higher temperatures have directly inhibited algal photosynthesis

d. the amount of carbon dioxide dissolved in the ocean has decreased

Positive feedback might occur in response to increasing atmospheric carbon dioxide levels as a result of

Select one:

a. soil decomposers increasing the rate at which they break down organic molecules

b. oceans absorbing more carbon dioxide in the form of bicarbonate ions

c. an increase in the rate at which fossil fuels are formed

d. plants accelerating their growth by taking up more carbon dioxide

Which nitrogen-containing molecules in soil represent a usable source of nitrogen for plants?

Select one:

a. Nitrogenous bases of nucleic acids

b. All of these

c. Ammonium

d. Amino acids

In a tropical forest ecosystem, "edgeâ habitat is considered to be of relatively low quality for conservation purposes because it

Select one:

a. tends to contain more invasive species

b. all of these

c. tends to contain more early-successional species

d. is more exposed to the effects of wind

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ES101 Lecture Notes - Lecture 19: Primary Production, Tropical Rainforest

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