1. Biology Standard 6: Ecology!
The student will demonstrate an understanding of the interrelationships among organisms and the biotic and abiotic components of their environments.

2. B-6.1 Explain how the interrelationships among organisms (including predation, competition, parasitism, mutualism, and commensalism) generate stability within ecosystems.
Key Concepts:
Ecosystem:
stable ecosystem
Predation:
predator, prey
Competition:
niche
Symbiotic relationships:
parasitism, mutualism, commensalism
An ecosystem is defined as a community (all the organisms in a given area) and the abiotic factors (such as water, soil, or climate) that affect them.

3. A stable ecosystem is one where…
population #s of each organism
fluctuate at a predictable rate
supply of resources in physical environment
fluctuates at a predictable rate
energy flows through ecosystem
at a fairly constant rate over time
These fluctuations in populations and resources ultimately result in a stable ecosystem!

4. Organisms in an ecosystem constantly INTERACT!
interactions among the organisms generate stability within ecosystems

5. Predation
interaction between species in which one species (the predator) eats the other (the prey)
helps regulate the population within an ecosystem thereby causing it to become stable
Fluctuations in predator–prey populations are predictable
At some point: prey population grows so numerous that they are easy to find, so predator population…

6. A graph of predator–prey density over time shows how the cycle of fluctuations results in a stable ecosystem.
As prey population increases, predator population increases.
As predator population increases, prey population decreases.

7. Competition
relationship that occurs when 2 or more organisms need same resource at same time
can be among members of same or different species
usually occurs with organisms that share the same niche
ecological niche:
role of an organism in its environment
including type of food it eats
how it obtains its food
how it interacts with other organisms
2 species with identical ecological niches cannot coexist in the same habitat!!
usually results in a decrease in population of a species less adapted to compete for a particular resource

8. Symbiotic Relationships
exist between organisms of 2 different species that live together in direct contact
balance of ecosystem is adapted to symbiotic relationship
If population of 1 or other of the symbiotic organisms becomes unbalanced, populations of both organisms will fluctuate in an uncharacteristic manner.
Symbiotic relationships include
Parasitism
Mutualism
Commensalism

9. Hornworm caterpillar
host will eventually die as its organs are consumed
by wasp larvae.
Parasitism +
symbiotic relationship in which one organism (the parasite) benefits at the expense of the other organism (the host
Some parasites live within the host
tape worms, heartworms, bacteria
Some parasites feed on the external surface of a host
aphids, fleas, mistletoe
Generally, parasite does not kill the host…WHY?
Parasite-host populations that have survived have been those where neither has a devastating effect on the other.
Parasitism that results in rapid death of host is devastating to both parasite and host populations.
important that host survive and thrive long enough for parasite to reproduce and spread
Parasitism _

10. Mutualism symbiotic relationship in which both organisms benefit
Because 2 organisms work closely together, they help each other survive.
For example:
bacteria, which have the ability to digest wood, live within the digestive tracts of termites
plant roots provide food for fungi that break down nutrients the plant needs

11. Commensalism
symbiotic relationship in which one organism benefits and the organism is not affected
For example,
barnacles that attach to whales are dispersed to different environments where they can obtain food and reproduce
burdock seeds that attach to organisms and are carried to locations where they can germinate Ø
Our eyelashes are home to tiny mites that feast on oil secretions and dead skin. +
Eyelash mites find all they need to survive in the tiny follicles of eyelashes.

12. REVIEW!
EXPLAIN how the interrelationships among organisms generate stability within ecosystems
cause-and-effect model showing how predation, competition, parasitism, mutualism, and commensalism affect the stability of an ecosystem
summarize how a stable ecosystem is obtained
identify or illustrate the roles of various organisms in an ecosystem (predator, prey, parasite, host) using pictures, diagrams, or words
interpret a graph of predator/prey numbers over time
explain how the numbers of various organisms fluctuate in an ecosystem to maintain stability
exemplify biological relationships
explain how a significant change in the numbers of a particular organism will affect the stability of the ecosystem
classify a symbiotic relationship as mutualism, parasitism, or commensalism
summarize each of the types of biological relationships
compare how various types of biological relationships affect the organisms involved

13. B-6.2 Explain how populations are affected by limiting factors (including density-dependent, density-independent, abiotic, and biotic factors).
Key Concepts:
Population:
population density
Limiting factors:
density-dependent
density-independent
Abiotic
Biotic
A population is a group of organisms belonging to the same species that live in a particular area. Populations can be described based on their size, density, or distribution.

14. Population density
measures the number of individual organisms living in a defined space
Regulation of a population is affected by limiting factors that include
density-dependent
density-independent
Abiotic factors
Biotic factors

15. Density-dependent
Limiting factors that operate more strongly on large populations than on small ones.
Competition
Predation
Parasitism
Disease
triggered by increases in population density (crowding)

17. Density-independent
Limiting factors that occur regardless of how large the population is and reduce the size of all populations in the area in which they occur by the same proportion
abiotic (such as weather changes)
Human activities (such as pollution)
natural disasters (such as fires)

18. Abiotic and biotic factors
Abiotic factors
chemical or physical
water, nitrogen, oxygen, salinity, pH, soil nutrients and composition, temperature, amount of sunlight, and precipitation
Biotic factors
all the living components of an ecosystem
bacteria, fungi, plants, and animals
A change in either may decrease size of a population if it cannot acclimate, adapt to, or migrate from the change.
A change may increase size of a population if that change enhances its ability to survive, flourish or reproduce.

19. REVIEW! explain how populations are affected by limiting factor
cause-and-effect models of how each limiting factor (including density-dependent, density-independent, abiotic, and biotic factors) can affect a population in an ecosystem and in turn, the entire ecosystem.
summarize how limiting factors (as listed in the indicator) affect population size
exemplify or classify each type of limiting factor (as listed in the indicator)
compare density-dependent limiting factors to density-independent limiting factors and biotic limiting factors to abiotic limiting factors
infer the result of a change in a limiting factor on the size of a population

20. B-6.3 Illustrate the processes of succession in ecosystems.
Key Concepts:
Ecological succession
Primary succession:
pioneer species
climax community
Secondary succession
ecological succession: series of changes in an ecosystem when one community is replaced by another community as a result of changes in abiotic and biotic factors
two types: primary and secondary

21. Primary succession
occurs in an area that has not previously been inhabited
Bare rock surfaces from recent volcanic lava flows
rock faces that have been scraped clean by glaciers
a city street

23. Beginning of primary succession
depends on presence of unique organisms that can grow without soil and facilitate process of soil formation
Lichens (mutualistic relationships between fungi and algae)
some mosses
Break down rock into smaller pieces
Among the most important pioneer species (the first organisms) in the process of primary succession
At this stage of succession there are the fewest habitats for organisms in the ecosystem.
Once enough soil and nutrients:
small plants, such as small flowers, ferns, and shrubs, grow
plants break down rock further, provide more soil
Then seeds of other plants and small trees are able to germinate and grow
Over time more species grow and die.
decomposed bodies add nutrients to soil
larger plant species able to populate area

24. Ch-Ch-Ch-Ch-Changes! As the species of plants change,
species of animals able to inhabit the area also change!
organisms in each stage may alter ecosystem in ways that hinder their own survival but make it more favorable for future organisms
In this way, one community replaces another over time.

25. As long as no disturbances occur...
composition of species perpetuates itself
climax community of a particular area is determined by limiting factors of the area
As scientists have studied changes in ecosystems
found that processes of succession are always changing ecosystems

26. Secondary succession
begins in area where there was a preexisting community and well-formed soil
abandoned farmland
vacant lots
clear-cut forest areas
open areas produced by forest fires
similar to later stages of primary succession
after soil has already formed
Something halts the succession (fire, hurricane, human activities)
destroys established community but soil remains intact
When disturbance is over, ecosystem interacts to restore original condition of community

27. Succession is a continual process
Some stages (and organisms that compose communities that characterize these stages) may last for a short period of time, while others may last for hundreds of years.
Any ecosystem disturbance will affect rate of succession in a particular area
Usually secondary succession occurs faster than primary succession because soil is already present
When disturbances are frequent or intense
area will be mostly characterized by species present in early stages of succession
When disturbances are moderate
area will be composed of habitats in different stages of succession
succession occurs in all ecosystems
forest succession
pond succession
coral reef or marine succession
desert succession

28. Which is primary? Secondary?

29. REVIEW! illustrate the processes of succession in ecosystems
show how one biological community replaces another community
identify communities that characterize the stages of succession
explain the environmental conditions that are necessary for pioneer species to survive;
infer what type of organisms will be present in a given area in the future based on the a description of the area’s current species
exemplify the conditions for primary and secondary succession
summarize the processes of primary and secondary succession

30. B-6.4 Exemplify the role of organisms in the geochemical cycles (including the cycles of carbon, nitrogen, and water).
Key Concepts:
Geochemical cycles
Carbon cycle
Nitrogen cycle:
elemental nitrogen, nitrogen fixation, denitrifying bacteria
Water cycle (hydrologic cycle)
Role of organisms in the geochemical cycles

31. Geochemical cycles
movement of a particular form of matter through living and nonliving parts of an ecosystem
Earth is a closed system and must continually cycle its essential matter
Matter changes form but is neither created nor destroyed; it is used over and over again in a continuous cycle.
Organisms are an important part of this cycling system!
Matter placed into biological systems is always transferred and transformed.
Matter, including carbon, nitrogen, and water, gets cycled in and out of ecosystems.

32. Carbon Cycle
Carbon = one of major components of biochemical compounds of living organisms
proteins, carbohydrates, lipids, nucleic acids
Found in
Atmosphere
In many minerals and rocks
Fossil fuels (natural gas, petroleum, and coal)
In the organic materials (compose soil, aquatic sediments)

33. Organisms play a major role in recycling C from 1 form to another:
Photosynthesis:
Photosynthetic organisms take in CO2 from atmosphere and convert it to simple sugars
Respiration:
Organisms break down glucose
C is released into atmosphere as CO2
Decomposition:
When organisms die, decomposers break down C compounds
Enrich the soil or aquatic sediments
are eventually released into atmosphere as CO2
Conversion of biochemical compounds:
Organisms store C as carbs, proteins, lipids, and nucleic acids
When animals eat plants and animals, some compounds used for energy
others converted to cmpds suited for predator’s body
other compounds (methane, other gases) released to atmosphere

34. Other methods of releasing stored C:
Combustion:
Burning wood or fossil fuels releases CO2 into atmosphere
were formed from once living organisms!
Weathering of carbonate rocks
Bones, shells fall to ocean/lake bottom
incorporated into sedimentary rocks (calcium carbonate)
Sedimentary rocks weather and decompose
C released into ocean, eventually into atmosphere

36. Nitrogen Cycle Nitrogen critical component of amino acids found in
needed to build proteins in organisms
found in
atmosphere as elemental nitrogen (N2)
in living organisms (as proteins and nucleic acids)
in organic materials that compose soil and aquatic sediments

38. Organisms play a major role in recycling N from one form to another:
Nitrogen-fixation:
Nitrogen-fixing bacteria convert elemental N found in air/dissolved in water into forms available for use by plants
found in soil, root nodules of plants, aquatic ecosystems
Intake of N into the organisms:
Plants take in the N through their root systems as ammonia or nitrate
N enters the food chain!
Decomposition:
Decomposers return N to soil
organism dies
animal waste products
Denitrification:
Denitrifying bacteria break down N compounds in soil
Release elemental nitrogen, N2, into atmosphere

39. Water Cycle (Hydrologic cycle)
necessary for life processes of all living organisms!
found in
Atmosphere
On surface of Earth
Underground
In living organisms
water cycle driven by Sun’s heat energy
causes water to evaporate from water reservoirs (the ocean, lakes, ponds, rivers) on Earth and also from organisms

40. Organisms play a role in recycling water from one form to another:
Intake of water into the organisms:
Organisms take in water and use it to perform life functions
Photosynthesis
transport of nutrients
Transpiration:
Plants release water back into atmosphere through transpiration
evaporative loss of water from plants
Respiration:
All organisms metabolize food for energy
Produce water as a by-product of respiration
Elimination:
Most organisms need water to assist with elimination of waste products

42. REVIEW! exemplify the role of organisms in geochemical cycles
give examples of the ways that organisms are involved in nutrient cycles, such as the nitrogen cycle, the carbon cycle, and the water cycle
summarize the ways that organisms are a vital part of each cycle (carbon, nitrogen, and water) in various ecosystems
interpret a diagram, description, or illustration of an ecosystem in order to describe how various organisms play a major role in the cycling of nutrients
explain the role of various organisms on the carbon, nitrogen, and water cycles

43. Key Concepts: Atmosphere: Geosphere: Hydrologic cycle
B-6.5 Explain how ecosystems maintain themselves through naturally occurring processes (including maintaining the quality of the atmosphere, generating soils, controlling the hydrologic cycle, disposing of wastes, and recycling nutrients).
Key Concepts:
Atmosphere:
ozone layer, greenhouse effect, sink
Geosphere:
soil erosion, deposition
Hydrologic cycle
There are naturally occurring Earth processes that help ecosystems maintain the materials necessary for the organisms in the ecosystem.

44. Earth systems are interconnected
Biosphere
Portion of Earth inhabited by life
Atmosphere
Hydrosphere
Geosphere
All must interact efficiently in order for an ecosystem to maintain itself.

45. Maintaining the Quality of the Atmosphere
composition of Earth’s atmosphere is mostly result of life processes of organisms which inhabit Earth (past and present)
Photosynthetic organisms need to produce enough oxygen for themselves and all other organisms on Earth
maintain balance of atmospheric CO2 and O2
Oxygen produced through photosynthesis is also responsible for the atmosphere’s ozone layer
prevents much of the Sun’s ultraviolet radiation from reaching Earth’s surface
protects biosphere from harmful radiation

46. Maintaining the Quality of the Atmosphere, cont’d.
normal cycling of O2 and CO2
occurs as plants produce more O2 (photosynthesis) than they consume (respiration)
animals use this O2 (for cellular respiration) and release CO2
used by plants in photosynthesis
Nitrogen is maintained in the atmosphere through the N cycle

47. Maintaining the Quality of the Atmosphere, cont’d.
Water is maintained in atmosphere through water cycle
water vapor condenses in atmosphere
impurities (dust and particulates) removed from atmosphere
fall to Earth with precipitation
air is cleaned after a rain or snow fall

48. Greenhouse effect
normal warming effect when gases trap heat in atmosphere
Greenhouse gases trap heat energy & maintain Earth’s temperature range
carbon dioxide, oxygen, methane, and water vapor
Don’t allow heat to pass through very well
heat that Earth releases stays trapped under the atmosphere

50. Carbon dioxide in the atmosphere
Amount cycles in response to
the degree to which plants and other photosynthetic organisms cover Earth and absorb carbon dioxide
the degree to which oceans cover Earth
salt water of oceans acts as a sink for carbon dioxide, absorbing what plants do not use
converting it to various salts such as calcium carbonate

52. Generating Soils part of geosphere
Soils on Earth are constantly being generated and eroded
4 distinct components –
inorganic minerals, organic matter, water, air
Process of soil generation continues:
weathering of inorganic materials from wind, water, and ice
decaying of organic materials
Soil erosion and deposition are natural processes that move soil from one location to another due to water, wind, ice and other agents.
In most areas, presence of plants allows process of soil production to be consistent with process of soil erosion so that overall amount of soil remains constant.
presence of soil in an ecosystem allows for succession to take place!

53. Controlling the Hydrologic Cycle:
maintained by energy of Sun and effect of weather
Purifies water in several ways:
Evaporated water is pure water containing no impurities.
As water seeps down through soil and rock it’s physically filtered of impurities.
As water flow slows, heavier particles of sediment settle out, leaving purified water to travel toward the oceans.

54. Disposing of Waste & Recycling Nutrients
Waste materials from organisms are decomposed by bacteria or other organisms in soil or aquatic ecosystems
Nutrients cycled through ecosystem from organisms to environment and back
series of specific processes
geochemical cycles

55. REVIEW!
explain how ecosystems maintain themselves through naturally occurring processes
Cause-and-effect model showing how the natural processes including maintaining the quality of the atmosphere, generating soils, controlling the hydrologic cycle, disposing of wastes, and recycling nutrients of Earth maintain the environment.
summarize how various aspects of an ecosystem are naturally maintained (quality of the atmosphere, generation of soils, controlling of the water cycle, disposing of wastes, and the recycling of nutrients.)
interpret diagrams, charts, tables, and graphs in order to describe how naturally occurring processes maintain balance in an ecosystem
exemplify various naturally occurring processes that ensure the quality of the atmosphere, the generation of soils, the control of the water cycle, the disposal of wastes, and the recycling of nutrients

56. Humans play a role in ecosystems and geochemical cycles
B-6.6 Explain how human activities (including population growth, technology, and consumption of resources) affect the physical and chemical cycles and processes of Earth.
Key Concepts:
Carrying capacity
Sustainability:
population growth, technology, consumption of resources
Technology:
agricultural, industrial, alternative energy
Resources:
renewable, nonrenewable
Humans play a role in ecosystems and geochemical cycles

57. People depend on...
resources and geochemical cycles of Earth to provide
clean water
breathable air
soil capable of supporting crops
Human activities can affect cycles and processes of Earth
Population growth
Technology
Consumption of resources

58. Carrying capacity sustainability
maximum population size that can be supported by available resources
Various factors determine carrying capacity of Earth for human population
energy, water, oxygen, nutrients
sustainability
meet the needs of humans to survive indefinitely
needs to be a balance between
Earth’s resources and carrying capacity
needs of humans and needs of other species on Earth

59. Factors that affect the sustainability of humans:
Population Growth
Technology
Consumption of Resources

60. Human Population Growth
grown exponentially world-wide
Scientists predict population will continue to grow at a rapid rate
Based on current trends

61. Natural slowing of population growth as it nears Earth’s carrying capacity
due to an increase in death rate and a decrease in birth rate
Result of:
Food and water shortages
Pollution of the environment
Spread of diseases

62. Increasing human population
can have effect on amount of available clean water
If clean water depleted at greater rate than it can be purified
It is not considered renewable in our lifetime

63. Increasing human population
can have effect on amount of waste produced
Although there are mechanisms in place to control disposal of some waste products,
more waste is produced than can be managed effectively
Some waste products require complicated, costly means for removal once introduced into environment

64. Increasing human population
can have effect on amount of available fertile soil for agriculture (food resources)
Soil is often lost when land is cleared, making land unsuitable for agriculture.

65. Other Soil Problems
Worldwide demand for land (agriculture or habitation) has led to deforestation
Cut down forests  fewer trees to absorb atmospheric CO2
increase contributes to global warming by preventing heat from radiating back into space
Deforestation can increase erosion rate (wind and water) and decrease rate of soil generation

66. Even More Soil Problems!
Human population growth has depleted amount of fertile soil, clean water and available land in many areas of the world.
resources scarce
many natural processes are affected
water cycle
carbon cycle
nitrogen cycle
physical process of soil regeneration

67. Technology
Different types have applied scientific knowledge to help meet the needs of humans
find solutions to problems
develop products
Has benefited humankind, but has also contributed to pollution of the air, water, and land.
For sustainability, humans depend on technology to now provide cleaner energy sources, safer ways to deal with waste, and better methods for cleaning up pollution.
Technological advances in agriculture, industry, and energy can have a positive or negative impact on Earth.

68. Agricultural technology
Advances in agricultural methodology, tools, and biotechnology have improved the ability to grow crops to sustain a growing world population.
Sustainable agricultural practices can help conserve fertile soil and reduce soil erosion.
BUT---
Farm machinery (such as tractors and combines) consumes nonrenewable resources and can contribute to erosion and air pollution.
Addition of substances (such as fertilizers, pesticides, fungicides, livestock waste) to environment can alter soil composition and can have a positive or negative effect on water, carbon or nitrogen cycles.

69. Industrial technology
Advances in industrial technology have changed the world and have lead to developments in communication, transportation, and industry.
Development of certain chemicals (CFCs– chlorofluorohydrocarbons) contributes to ozone layer depletion
results in increased ultraviolet rays reaching Earth
CFCs used in
producing foam packing materials
cleaning electrical components
refrigeration chemicals (Freon)

70. Technological advances
have revolutionized the communication industry
BUT...disposal of outdated or damaged equipment is becoming an increasing concern!!

71. Burning of fossil fuels for industry and transportation increases sustainability of the growing human population, BUT it also:
increases greenhouse gases released in atmosphere (mainly carbon dioxide)
increases global temperatures (global warming) that affect sea levels, climate and atmospheric composition
produces acid rain (pollutants in the air combining with water to cause the normal water pH to be lowered)
decreases soil pH
can leach nutrients from soils or destroy plant life
changes pH of aquatic ecosystems
therefore affects types of organisms that can survive there

72. Alternative energy technology
Using natural renewable energy sources
wind, water, geothermal, or solar energy
decreases burning of fossil fuels
increases quality of atmosphere and cycles involved
Using nuclear energy technology provides an alternative energy source that does not impact the atmosphere.
BUT...waste produced from is becoming an increasing concern

73. Consumption of Resources
As human population increases and technology expands, demand for Earth resources also increases
BUT there is a limited supply of these resources available to sustain the human population!

74. Renewable Resources food, clean water, timber
can be produced at roughly the same rate that they are consumed
have factors that limit their production
amount of grain that can be produced is limited by
amount of land available for farming
fertility of the land
productivity of the grain
availability of clean water

75. Nonrenewable Resources
fossil fuels
cannot be produced at same rate they’re consumed
Demand for minerals, metals, and ores increases because these strategic materials are vital to industry but are decreasing in availability.
Minerals are nonrenewable because
mineral deposits that can be extracted economically are formed so slowly by geological processes that their formation as a means of replacing what we are using is NOT PRACTICAL!

76. Sustainable use of resources
can be accomplished by
reducing consumption
reusing products rather than disposing of them
recycling waste
Protect the environment!!

77. REVIEW!
explain how human activities affect the physical and chemical cycles and processes of Earth
cause-and-effect models of how human population growth, technology, and consumption of resources can influence the geochemical cycles and processes of Earth
interpret diagrams, charts, tables, and graphs in order to describe how human activities affect the geochemical cycles and process of Earth
summarize how various human activities affect the geochemical cycles and processes of Earth;
illustrate ways that the geochemical cycles and processes of Earth have been altered by human activities
infer the future effect of human activities on the geochemical cycles and processes of Earth based on current trends