Lecture 1

Question 1

Ecosystem

Answer 1

all the organisms in a given area, along with the nonliving (abiotic) factors with which they interact; a biological community and its physical environment.

Ecosystems exist at many spatial scales (e.g., from ponds to the entire biosphere)

Question 2

what does Ecosystem ecology examines?

Answer 2

Ecosystem ecology examines the flow of energy and chemical cycling in habitats, as well as, the effects of
natural and human-induced disturbances on ecosystems (e.g., air/water pollution, tree harvesting, land-use changes….)

Question 3

Energy Flow

Answer 3

the passage of energy through the components of an ecosystem

Question 4

Chemical Cycling

Answer 4

unlike energy flow, chemical cycling involves the circular (recycling) movement of materials within the ecosystem

For example, a terrarium as an ecosystem

Question 5

Ecosystems consist of ____ & ___ components

Answer 5

Ecosystems consist of biotic & abiotic components

Question 6

Biotic

Answer 6

all living organisms in an area (community)

Question 7

Abiotic

Answer 7

physical environment with which the organisms interact

Question 8

Abiotic & biotic components exchange _____ & _____ (e.g., nutrients)

Answer 8

Abiotic & biotic components exchange energy & materials (e.g., nutrients)

Question 9

Abiotic Inputs into the ecosystem include:

Answer 9

• Energy (radiant)
• Inorganic substances (CO2, N, O2, minerals)
• Organic substances (e.g., proteins, carbohydrates, humic acids)
• Water

Question 10

Energy (radiant)

Answer 10

Energy (radiant) is an overriding factor that affects temperature, moisture, seasons, and photosynthetic energy

Question 11

temperature and moisture

Answer 11

temperature and moisture strongly influence the type of organisms present and the productivity of a given system

Question 12

Biotic inputs into the ecosystem

Answer 12

1. Organisms that move into an ecosystem (e.g., animal migrations)
2. Influences from adjacent ecosystems
   For example, upstream ecosystems or downwind ecosystems; ocean currents, ……..

Question 13

Radiant Energy

Answer 13

•Majority of radiant energy reaching the planet is converted to heat Warms Earth & the Atmosphere, and in turn:

1. Drives the hydrologic (water) cycle
2. Generates air currents (winds) and ocean currents

•A small amount of radiant energy reaches photosynthetic organisms where it may be converted to photochemical energy
This photochemical energy is stored in ~170 billion metric tons of organic material produced globally per year

Question 14

What is energy?

Answer 14

The capacity to do work

• Energy can only be described and measured by how it affects matter
• Energy is required to move matter in a direction it would not move if left alone
• All organisms require energy from their surroundings in order to stay alive

Question 15

Familiar Forms of Energy

Answer 15

Thermal energy (heat) 
Radiant energy (e.g., light) 
Kinetic energy (motion) 
Chemical energy

Question 16

photosynthesis:

Answer 16

radiant energy chemical energy (e.g., sugars)

Question 17

Energy Conversions Laws

Answer 17

1) Universal laws govern how one form of energy can be converted to another
2) These laws apply equally to living and non-living things

3) The laws governing energy conversion are called
the laws of thermodynamics

Question 18

Thermodynamics:

Answer 18

the study of energy transformations (conversions) that occur in a collection of matter

Question 19

Energy Conversions Follow Two Laws

Answer 19

First Law: energy is neither created nor destroyed.

Second Law: conversion of energy from one form or another is always accompanied by a reduction in the order of the universe

OR

When energy is converted from one form to another, some of the energy becomes unavailable to do work

Question 20

With each conversion of energy, the energy available to Do Work ____

Answer 20

Declines

Question 21

The amount of disorder in a system =

Answer 21

Entropy

Question 22

Heat can be considered a form of ______ because it represents RANDOM motion of molecules

Answer 22

Heat can be considered a form of entropy because it represents RANDOM motion of molecules

Question 23

Autotrophs (self-feeders):

Answer 23

an organism that makes its own food , thereby sustaining itself without eating other organisms or their molecules

•Plants, algae and photosynthetic bacteria are autotrophs

Question 24

Photosynthesis:

Answer 24

process by which photosynthetic organisms synthesize food molecules from carbon dioxide and water
by using light energy.

Note, only ~1% of the PAR that reaches the autotrophs is actually converted to chemical energy (e.g. sugars)

Question 25

Primary production:

Answer 25

the rate at which photosynthetic organisms (autotrophs) convert solar energy to chemical energy (organic compounds)

Question 26

Biomass or standing crop:

Answer 26

the amount of living organic material in an ecosystem (or a subcomponent of the ecosystem, e.g., in plants)

Question 27

the primary productivity of the biosphere is

Answer 27

170 billion tons of biomass per year