1. Unit D: Changes in Living Systems
Science 20: Chapter 1
The Biosphere of Life

2. 1.1) Biosphere The narrow zone around the earth where life exists.
Biosphere consists of 3 components:
Lithosphere, Hydrosphere and Atmosphere.
Biotic = living organisms (life forms).
Abiotic = nonliving component (geological and physical factors).

4. Ecological studies investigate a specific environment by looking at the following:
Organism (the individual).
Population (group of individuals).
Community (1 or more populations).
Ecosystem (community and abiotic factors interact).
* Example: Prairie ecosystem; who’s who?

5. 1.1b) Habitat
Water is the most important abiotic factor of an ecosystem.
The habitat of an organism determines the amount of water, sunlight and temperature for growth and survival.
Habitat = abiotic and biotic factors that encourage survival.
What is your ideal habitat? Why?

6. 1.1c) Nutrients
Nutrients are needed compounds/elements used by organisms to grow and reproduce.
Gardeners use fertilizers to give all the needed nutrients to the plants.
The run-off from fertilizers can cause problems with lakes and algal blooms.

7. Fertilizers
fertilizer - chemicals that contain nitrogen and phosphorus natural fertilizer
Manure: contains N which is ammonified first in the soil, then nitrified to provide useful nitrates
Commercial Fertilizers: 3 numbers:
The first number is the % nitrogen (by weight)
The second number is the % phosphorus (by weight)
The third number is the % potassium (by weight).

9. pollution increases the natural eutrophication process of water. Why?
Unnatural Eutrophication: a process in which nutrient runoff from agricultural lands or livestock operations causes photosynthetic organisms in ponds and lakes to multiply rapidly
Human-caused eutrophication wiped out fisheries in Lake Erie in the 1950s and 1960s.
algal blooms are harmful rapid growth of algae, causing eutrophication.

10. LAKE EUTROPHICATION
Algae die = food for decomposers = population grows
High levels of P and N containing compounds (fertilizers/ detergents)
Algal Bloom
Low oxygen = other organisms die out
Decomposers break down material and use up oxygen in lake
Organisms living in this part of the lake also feed on decaying plant and animal remains that wash into the water from the land
Freshwater biomes located near areas with human populations often contain high concentrations of phosphorus and nitrogen compounds
These compounds come from fertilizers and detergents used by people
Phosphorus and nitrogen compounds that enter lakes, ponds, and streams serve as nutrients for algae and plants
But if too many nutrients are present, algae and plants may grow out of control
These large populations eventually begin to die and decay
As decomposing bacteria break down the remains, they use up much of the oxygen dissolved in the water
The resulting oxygen-poor water becomes uninhabitable for protozoa, fish, and other small animals
Water in which oxygen becomes too low to support animal life is called eutrophic.
To protect Canadian lakes, ponds, and streams from becoming eutrophic, some states no longer allow the sale of detergents containing phosphorus compounds. 10 10

11. Classification of lakes by the nutrient input which also determines
the primary producers.
Oligotrophic lake: Nutrient-poor, photosynthesis-limited, clear water, O2 rich.
Eutrophic lake: Nutrient-rich, high photosynthesis, murky water, O2 poor.

12. 1.1e) Hydrological cycle Water plays a critical role by:
Maintaining global heat balance.
Acting as a solvent in reactions.
Movement of water through environment: from atmosphere to earth.
Volume of water remains constant, specific amounts vary in phases; water continuously cycles.

13. The Hydrologic Cycle

16. 1.2) Biotic factors
Ecology = study of the interactions of living organisms with their environment and each other.
Biomass = dry mass of all organisms in an environment.

17. 1.2b) Symbiosis Symbiosis = “living together” Types of symbiosis:
Long lasting relationship that benefits at least 1 organism of 2 different species
Types of symbiosis:
Mutualism: both species benefit.
Commensalism: 1 organism benefits, the other is unaffected/unharmed.
Parasitism: 1 organism (parasite) benefits by harming the other (host).

18. See page 417 and identify the relationships!

19. 1.2c) Predator-Prey Interactions
This is NOT symbiosis; the 2 organisms do not live together and it is a short interaction.
Predation: 1 organism(predator) kills the other (prey).
Mostly benefits the predator BUT the prey community is left with fit individuals.

20. What type of relationship is this?

21. 1.2d) Competition
Competition is where 2 or more organisms compete for the same resource.
All organisms involved are harmed; no one benefits.
This is NOT symbiosis.

23. Assignment Please complete the following:
Read and highlight the important points on “biomes and habitats” and “animal partnerships”.
Complete #2,3 and 4 on page 412.
Complete the Symbiosis Fact sheet.
Complete #2,3,5 on page 422.

24. 1.3) The web of life
Matter and energy are essential components of the universe and living organisms.
Matter - everything that takes up space and has mass
Energy - the capacity to do work
the biosphere is composed of a variety of ecosystems
each ecosystem has a structure based on
a) energy flows
b) matter cycles

25. 1.3b) Ecosystem Structure
An ecosystem = all the organisms living in a community and all the abiotic factors they interact with.
1) Autotroph (producers)
organisms that:
get energy from sunlight or inorganic energy sources.
convert inorganic compounds to organic forms.
are the basic trophic level in an ecosystem; supports all other organisms
Trophic level = category of organisms defined by how they get energy.

27. Heterotroph (consumers) : organisms that derive their energy by consuming other organisms.
a) Primary Consumers
- herbivores (eat only plants)
b) Secondary and Tertiary Consumers
- carnivores (eat other animals)
- omnivores (animals which eat both producers and consumers)

32. 1. scavengers (eat tissues from dead organisms).
Decomposers
- organisms that derive their energy from dead organisms and waste products.
1. scavengers (eat tissues from dead organisms).
2. Decomposers (breaks down complex molecules into simple sugars)
Why is decomposition important?
recycles organic material into inorganic

34. 1.3c) Trophic Levels in Ecosystems
the steps in the transfer of energy and matter within a community (feeding levels)
species in an ecosystem are divided into trophic levels on the basis of their main source of nutrition.
three main types of trophic levels are producers, consumers, and decomposers.

35. Count trophic levels as steps from the original energy source
We classify organisms in relationship to how they acquire food in the following way. There are typically very few tertiary-level carnivores because of the loss of energy during the transfers to each level…remember the two laws of Thermodynamics. We can't get away from their limitations. 35

36. Food chain movie
1.3d) Food Chains
organization of trophic levels where energy flows from producer to primary and secondary consumers (and others if present)
Simple feeding sequence:
who eats who
Not representative of complex ecological relationships
Trophic
Levels

38. Food Chain - simplistic

39. 1.3e) Food Webs
interconnected food chains within an ecosystem
highlight the complex, real-world interactions between species
makes connections from primary producers, through consumers, and back to decomposers
Food Chain Movie

42. Food Web - complex

43. Interactions in an aquatic food web

44. IV. Ecological Pyramids

45. 1.3f) Ecological Pyramids
Because of the loss of energy with trophic levels, there are two consequences for the ecosystem:
Because productivity is lower at higher trophic levels, there is less biomass at these levels
2. Lower biomass at higher trophic levels, combined with large body size of top consumers, results in lower population densities

46. Most stable ecosystems have complex and well developed food webs  the removal of one of its organisms may have little effect

47. results in a stepwise decrease in energy (pyramid)
there are 3 types of pyramids in common use by ecologists

48. - # of organisms at each trophic level - each bar represents
Pyramid of numbers
- # of organisms at each trophic level
- each bar represents
numbers relative
to the pyramid base
- pyramids are based on data from a given area eg: 1 km 2
tertiary consumer
secondary consumer
Primary consumer
Producer

49. b) Pyramid of Energy
- energy stored by each trophic level is given in calories or Joules. Energy per unit area per unit time (Kcal/m2/yr).

50. Efficiency of energy transfer:

51. – stored energy is represented by biomass (dry weight)
Pyramid of Biomass
– stored energy is represented by biomass (dry weight)
Biomass per unit area per unit time (g/m2/yr)

52. Energy is lost at each step in a food chain or web; the general estimate of this loss at each step is 90%, so only 10% of energy consumed is available to the next trophic level. This is known as the 10% rule.

53. Energy Loss –
Energy flow not,
Energy cycling
Energy lost as heat

55. Could we feed a larger population of humans if we ate only plants?
Yes, since most of the energy in ecosystems is stored in the bodies of primary producers. Only about 10 percent of the energy at one energy level passes to the next highest trophic level, therefore less individuals can be fed at higher levels.

56. The behavior of energy is best explained by the Laws of Thermodynamics.
Where do photosynthesis and cellular respiration fit in? What are they?

57. Laws of Thermodynamics: a) First Law of Thermodynamics
Energy cannot be created or destroyed, only changed from one form to another
b) Second Law of Thermodynamics
With each successive energy transfer, less energy is available to do work. In biological systems, this “waste” energy is often heat.

59. Assignment Please complete the following:
Practice #2 worksheet #1,4,5,8.
Investigation #2 worksheet: Complete entire lab (#1-8, extension).

60. 1.4) Planning Field study
Complete the elk island field study.

61. 1.5) Recycling of matter Matter is recycled, but energy is not.
Even when trees die from a fire, their seeds do not and plant new seedlings.
Recycling happens through biogeochemical cycles: the movement of elements/compounds between abiotic and biotic parts of the environment.

62. 1.5a) The Carbon and Oxygen cycle
Cycling of Carbon and Oxygen.
Carbon is a component of all living and dead organisms; considered organic.
Plants perform Photosynthesis (Carbon dioxide --- glucose) and Animals/Plants perform Cellular respiration (Oxygen --- Carbon dioxide and energy).
Soil organisms (bacteria) decompose dead organisms and return carbon.
Reservoirs of carbon = carbon sinks.

63. carbon cycle animation

64. b. Fossil fuels
Dead organisms are compressed into fossil fuels; when it is burned, it releases carbon into the atmosphere.
Added Carbon disrupts natural cycling, leading to climate change.
The Greenhouse effect: Carbon Dioxide traps energy in the atmosphere and increases the temperature of the earth.

65. c. Greenhouse effect
Greenhouse Effect - animated diagram

68. 1.5b) Nitrogen cycle
Includes 4 Processes: Nitrogen fixation, ammonification, nitrification and denitrification.
Nitrogen is an important component of all proteins and nucleic acids.
Most organisms can’t use Nitrogen directly; it must be put into soli by:
Volcanic action.
Lightening.
Nitrogen- fixing bacteria.

69. Nitrogen fixation and Ammonification
Nitrogen fixation: bacteria (90%)/lightening (10%) convert atmospheric nitrogen into roots of plants (legumes).
Fertilizers increase this amount.
Ammonification: Decomposers convert nitrogen products (from tissues) into ammonia (NH3).

70. Nitrification and Denitrification
Nitrification: process changing ammonium ions into nitrates (NO3), performed by nitrifying bacteria.
Absorbed by plants, used to make a.a’s: absorbed by consumer when eaten.
Denitrification: Bacteria convert ammonia into Nitrogen, which returns to atmosphere.

71. nitrogen cycle animation

74. Pesticides Pesticides have had the largest impact on food webs
Pesticides benefit society
reduce the number of pests (weeds, molds, insects, birds, etc.) to increase crop production
Reduce the spread of disease (malaria, West Nile)
Pesticides have also negatively affected ecosystems:
Eliminating an insect species on small island using DDT reduced the spread of malaria, however, the entire food web of the island was affected: other insects disappeared - then lizards - then cats - increasing rat population – outbreak of disease = more problems!!!
Biological amplification/ magnification – the buildup of toxins as you move up a food chain.
Therefore, the higher the trophic level, the greater the concentration of toxins
Toxins affect the environment in unexpected ways.. Example: DDT accumulation in the Peregrine Falcon creates thin shells, therefore breaking easily. The numbers of the species in Canada decreased so dramatically, that they were close to extinction.

75. Human use of
Pesticides
Soluble in water,
Collects in fatty tissue
DDT interfered with
Calcium deposition

76. Time magazine in 1947

77. Assignment Please complete the following: Carbon and Oxygen Cycle.
Nitrogen cycle.
Finish labeling all of the cycles!

78. Chapter 2: Changing Populations
Science 20: Unit D
Chapter 2: Changing Populations

79. 2.1) Ecological Succession The Process of Succession
Describe the community in the picture on the right.
Ecological succession is a community change in which new populations of organisms gradually replace existing ones
Succession occurs from natural causes (competition, fire, earthquakes, etc) or due to man (logging, mining, farming etc).
The resources available in a particular area are limited
Members of a community must often compete with each other for food, shelter, and sunlight
Competition may eliminate one or more of the populations living in a community
The populations may move to a new lo­cation, or its members may die
A change in one community population can sometimes create new conditions by affecting the niches of remaining community members
The niches of organisms can also be affected by such factors as fire, floods, earthquakes, and volcanoes
When new conditions are introduced into a community, organisms that could not live in the area before may be able to make their homes there 79

80. Primary Succession Animation
Primary succession-Succession that begins in an area where there is no existing community
Causes of prim Succession: volcanic eruption, glacier retreat
The first group of organisms to occupy an area undergoing primary succession is called a pioneer community
Pioneer organisms must be hardy and able to live on minimal resources
Lichens are pioneer organisms; humus is the organic component of soil created from decomposing organisms.
Primary Succession:
Succession may begin in an area where there is no existing plant or animal life
Usually, such a succession begins when a major occurrence, such as fire or a volcanic eruption, completely destroys the soil and the organisms living in an area
Pioneer Community:
Unlike most organisms, lichens can grow on bare rock, as well as in soil and on the bark of trees
Lichens produce acids that break down the rock by slowly dissolving the minerals
As lichens die, their remains also add to soil formation
Primary Succession Animation 80

81. Steps in Primary Succession:
Soil formation (lichens die/ break up rock)
Glacier Retreats exposing Parent rock
Pioneer community (lichens, mosses)
Increased soil = shallow rooted trees (pine)
Grasses die = more soil = shrubs and weeds take over
Enough soil = grasses out compete lichens
Soil formation is usually the first step in primary succession
In time, enough soil accumulates to support the growth of grasses
The grasses germinate from seeds carried into the area by wind or animals
When the grasses become dense enough, there is no longer enough light or space to support the growth of lichens, and they disappear from the community
After the grass community has thrived for many generations, the soil becomes deeper and richer
In same areas, the soil becomes deep enough for shrubs and deeply rooted weeds to grow
The weed and shrub community begins to crowd out the grasses
At the same time, the soil-building process continues, with the soil becoming still richer and deeper
Over time, enough soil accumulates to support the growth of shallow-rooted trees such as pines
As more pines begin to grow, a pine forest may be established
In the shade of the pines, conditions may begin to favor germination of the seeds of other, more deeply rooted trees, such as maple and beech
Eventually, the pines may be replaced by a forest of broadleaf trees
Increased pine = more shade = favorable for deeply rooted plant (maple/ birch)
Climax Community
*Climax community is the stable community that results. 81

82. Primary Succession Animation82

83. 2.1b) Aquatic Succession
Occurs when water collects in a basin; algae starts to grow; eggs are planted in water; fish hatch and attract birds to the water.
Nutrients from runoff create soil for plants to grow; plants grow on edge (cattails).
When lots of plants overtake water = terrestrial ecosystem.

85. 2.2) Secondary Succession
Secondary succession: occurs in an area where an existing community has been partially destroyed
Examples: Fires, logging, farming
Occurs more rapidly then primary succession
A community that achieves relative stability is called a climax community.
Climax communities tend to have greater species diversity than the communities that precede them.
Sometimes the balance in an existing community is upset, forcing out only same populations
Because soil is already present and the area has not been totally stripped of its plant life, secondary successions tends to occur mare rapidly than primary succession
Climax Communities
Eventually succession slows down, and a more stable community is established
This community is made up of organisms that are well-suited to the environment and are good at competing for resources
Sometimes frequent disturbances prevent succession from proceeding and actually cause a community to stabilize
In grasslands, for example, succession is limited by frequent fires caused by lightning
The fires prevent the seedlings of slow-growing woody plants from attaining enough height to compete with the rapidly growing tall grasses
In the arctic zone, permanently frozen soil, the short growing season, and frequent snow cover prevent the growth of deep-rooted trees and other large plants
With more species, there are more interactions among organisms
Some ecologists think that these interactions provide the "checks and balances" that help stabilize the community
However, even climax communities experience change when something disturbs their balance
If the balance is disturbed by a sudden natural disaster, a climax community can be quickly destroyed, and the process of succession may begin again 85

86. Why are there prescribed burns? Is this a good thing?

88. Assignment Please complete the following:
Environmental changes and succession worksheet (omit #1 and 2).
Sketch the process of primary and secondary succession, with labels, in your duo tang!

89. 2.3) Populations
Populations can grow so fast that they exhaust their resources. Examples?
Why is this a problem? Where do we see this happening today?
In order to study population growth, bacteria is used; it is easy to study and can imitate human populations very well.

90. 2.3b) Exponential Growth
The rapid growth in population caused by constant increase.
Growth rate is measured using doubling time- the time it takes for the population to double.
Exponential Curve (J curve): when data is graphed, the shape is a J. The population is increasing and growing exponentially.

92. 2.3c) Factors that affect populations
4 major factors:
Number of births (natality).
Number of deaths (mortality).
Immigration (movement in).
Emigration (movement out).
2 types of populations:
Closed: No movement in/out due to natural/artificial settings. Only death/births affect population.
Open: exist in natural setting where all 4 factors affect population size.
Density independent
Density dependent

93. 2.3d) Population explosions and crashes
If an organism is introduced where there are no predators; a population explosion/growth occurs.
What happens when the food is gone? The population crashes!
Example: Rabbits released in Australia (1859).
Curve shape: J curve (up and down).

95. 2.3e) Carrying Capacity
The maximum number of individuals that can be sustained by an ecosystem indefinitely; limited by disease, competition and famine.
Instead of crashing, the population levels off at a stable number of organisms.
Curve shape: S curve.

97. 2.3f) Malthus
Thomas Malthus was the first to hypothesize how populations grow.
He predicted that the human population would crash because of shortage of resources. Why did this not happen?
Do you think a population crash will occur? Why or why not?

98. Assignment Please complete the following: Population growth curves
Population regulation

99. 2.4) Adaptations
Snails- the perfect organism to study because they have been around for 500 million years.
Generations (a single step in the line of descent) can be found and the morphology (the shape and form of the organism) can be studied.
Help to shape the fossil record (the record of all fossils on earth).

100. 2.4b) Evolution
Means “change over time”: gradual changes in organisms happen over generations; eventually producing new species.
Occurs in a population, not single organisms.
Are genetics related changes.
2 versions:
Gradualism (Darwin).
Punctuated equilibrium (Stephen Jay Gould).

101. Gradualism vs. Punctuated Equilibrium
Organisms accumulate changes gradually over time, these slow changes eventually lead to new species.
Punctuated Equilibrium:
A new mutation that is favorable in a population will rapidly out compete the old genes = Sudden change!
Between times of rapid change are long periods of little natural selection.

102. 2.4c) Mechanism of inheritance
Each organism has 2 sets of genes (DNA passed from parent to offspring) that determine characteristics of the organism.
When genes are passed to offspring, they are copied and can mutate or change; this leads to variation in a species.
Mutations can be good or bad; they increase or decrease the probability of survival.

103. 2.4d) Types of Adaptations
accumulation of traits which improve a species ability to survive.
mechanism is natural selection
better-suited traits to environment are passed on.
Structural
modifications of shape and size to allow special functions
Examples: fingers of humans adapted to grasping/ holding; “fingers” of bat adapted to support wing
-leaves of pitcher plant
b) Physiological
development of chemicals in the organism
Examples: digestive chemicals in pitcher plant to digest insects
- venom of snakes
c) Behavioral
actions
Examples: migration, hibernation
Evolution: Library: Evolution of the Eye
pitcher plant

104. 2.5b) Lamarck’s Theory
Believed in spontaneous generation: new species created from non-living matter and gradually become more complex.
Known as “Inheritance of acquired characteristics”.
Organisms had a “force”/ “desire” that causes them to change for the better; must produce new parts to meet desire.
Use and misuse of parts passed to offspring.
Example: giraffes.

107. Darwin’s finches.
Watch the slideshow of the Galapagos islands; very cool!

108. 2.5c) Darwin’s theory
Theory developed while on board the HMS Beagle; returned in 1836.
Suspected the following:
Living forms descended from fossils.
Species evolve independently if isolated.
Evolution due to difference in habitat.
Geological forces responsible for location of fossils and mountains.
Evolution: Darwin

111. Galapagos Islands: A unique Island Ecosystem

112. 1) Natural Selection Central theory to Darwin’s evolution.
5 distinct areas:
Overproduction
Competition
Variation
Survival of the fittest (cartoon)
Origin of new species by inheritance of successful variations.
Evolution: Library: Sweaty T-Shirts and Human Mate Choice
Evolution: Survival

113. 2) Peppered Moth The Peppered Moth
The light-colored form of the moth, known as typica, was the predominant form in England prior to the beginning of the industrial revolution. Shown at left, the typica moth's speckled wings are easy to spot against a dark background, but would be difficult to pick out against the light-colored bark of many trees common in England.
Around the middle of the 19th century, however, a new form of the moth began to appear. The first report of a dark-colored peppered moth was made in By 1895, the frequency in Manchester had reached a reported level of 98% of the moths. This dark-colored form is known as carbonaria, and (as shown at right), it is easiest to see against a light background. As you can well imagine, carbonaria would be almost invisible against a dark background, just as typica would be difficult to see against a light background. The increase in carbonaria moths was so dramatic that many naturalists made the immediate suggestion that it had to be the result of the effects of industrial activity on the local landscape.
The Peppered Moth

114. - Organisms must compete for food, water and shelter. 3. Variation:
1. Overproduction:
- More offspring produced than can survive, reproduce and live to maturity.
2. Competition:
- Organisms must compete for food, water and shelter.
3. Variation:
- differences in species that are passed to offspring.
4. Natural Selection:
- Individuals that are well adapted to their environment are more able to compete, survive and reproduce
5. Inheritance of successful traits:
- Over generations, new species arise through inherited genes; a new species is produced.
Evolution: Sex: The Mating Game

115. originally, most giraffes had short necks, but some variation existed.
Darwin:
originally, most giraffes had short necks, but some variation existed.
as food supply on lower branches dwindled, short-necked giraffes did not survive; long-necked giraffes did survive.
“fitness” = measure of reproductive success.
“survival of the fittest” ---> only giraffes that were adapted for a longer neck (genetics) fit the environment.
long-necked giraffes were better suited to their environment, therefore more likely to survive and reproduce ----> long necked giraffes survived.
over a long period of time, the population of giraffes changed from mostly short- necked giraffes to mostly long-necked giraffes ---->EVOLUTION.
origin of species

116. 2.5d) Evidence for evolution
4 main areas:
Theory of Continental drift/Pangaea
Fossil records
Embryology
Comparative Biochemistry
Evidence comes from direct (fossils, continental drift) or indirect (embryology, biochemistry) investigations.

117. 1) Fossils
Fossil = remains of plants/animals preserved in rock/tar/amber/ice.
The fossil record shows organisms once existed on earth that don’t exist now; some bear resemblance to those that exist now.
Recent fossils resemble present day species; older fossils are more primitive.
Rocks are dated using radio-carbon dating.
Fossil record is not complete---- there are “missing links”.

118. Observe how fossils can form.

119. Observe an animation of clastic sedimentary rocks forming.

120. 2) Embryology Study of organisms in the early stages of development.
Embryos of all vertebrates are remarkably similar in early stages.
Embryologists suggest this is because all vertebrates evolve from a common ancestor. Many embryonic structures are similar to those found in ancestors.

122. a) Vestigial Structures
Muscles/Appendages that are considered to be useless.
Includes: tails, ear muscles, appendix and limb bone of whale.
Were these once useful?

124. b) Homologous structures
Have common origins in the embryo (ex. Gill slits), but may appear quite different in adults.
Have the same structure, but different functions.

126. d. Biochemistry
Analysis of DNA and proteins show that animals may have remarkably similar DNA.
Differences arise by mutations accumulated overtime.
The closer the “DNA fingerprint”, the more closely related the organisms are.

128. 2.5e) Asexual reproduction
To avoid mutations, asexual reproduction occurs in many plants. The parent clones an exact copy of itself = the daughter.
This happens with “cuttings” of plants, cloning of cells and “runners”.

130. Assignment Please complete the following: Homologous structures
Genes and Evolution
Mechanisms of Biological change
Chapter 2 review (odds only).
Remember that you have a unit exam on chapters 1 and 2; do review questions from both!
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