ECOLOGY

1
Ecology
2
5 Levels of Ecological Organization

• Species- organisms that can interbreed and
  produce fertile offspring
• Population- all the members of 1 species in an
  area
• Community- every species in an area
• Ecosystem- many communities
• Biosphere- The entire region of Earth where
  living things can be found (many ecosystems)

3
(No Transcript)
4
What is Ecology?

• Study of the interaction between organisms and
  their environment
• Within an ecosystem there are two main
  components.
• habitat- place where organism lives
• community- ALL the species in habitat

5
Species Interaction

• Many interactions take place between species in a
  community.
• i.e.) predator and prey
• Each organism plays a certain role in the
  community.
• Niche- role of organism in which it interacts
  with other species and its environment (i.e. its
  job)

6
Abiotic vs. Biotic Factors

• Abiotic- non-living components
• -ex) temperature, light, water, nutrients,
  boats
• Biotic- living species
• -ex) sea turtle, sea grass, coral, fish, humans

7
Biodiversity

• Biodiversity-The number of different species in
  an ecosystem.
• More plants more animals
• More biodiversity healthier ecosystem.

8
What Determines Biodiversity of Ecosystem?

• Size
• Latitude Closer to equator more diverse.
• a) More sunlight and longer growing season
• b) More producers (plants)
• Why do we call plants producers?
• c) More producers more consumers
• Precipitation (i.e. rainfall)

9
Conditions for Life

• For an ecosystem to sustain life, it must have
• 1) Constant source of energy (sun).
• 2) Living system that converts suns energy into
  organic molecules.
• -Producers (plants) Why?
• 3) Cycling of nutrients between organisms and
  environment (water, carbon dioxide, nitrogen,
  oxygen).
• 4) Decomposers return unused nutrients to the
  environment.

10
Photosynthesis Equation
KNOW THIS EQUATION! Producers are considered
autotrophs, or self-feeders because they can
make their own food. Consumers are considered
heterotrophs, or other-feeders because they
have to consume their food.
11
Nutritional Interactions

• All ecosystems must have interactions between
  producers, consumers, and decomposers.
• Producers (autotrophs)
• Consumers (heterotrophs)
• -herbivores
• -carnivores
• -omnivores
• -decomposers

12
Energy flow in an ecosystem

• Energy flows through an ecosystem from the sun to
  producers to consumers.
• Arrows show the way the energy flows.

13
Who Eats Who

• Food chain- straight line sequence shows simple
  feeding relationships
• Notice the direction of the arrows!
• Sun
• Producers
• Primary consumers
• Secondary Consumers
• Tertiary Consumers

14

• Food web- illustrates how the many food chains in
  an ecosystem are related
• Primary consumers?
• Secondary consumers?
• Tertiary consumers?
• Where would
• decomposers fit in
• this food web?

15
How many trophic levels are possible?

• Trophic means feeding
• Trophic levels -levels of feeding from producers
  (plants) to the consumers
• Few ecosystems have more than 4 or 5 trophic
  levels
• Energy diminishes at each level because it is
  used for lifes processes.
• Energy pyramids- show amount of energy at each
  trophic level.
• These are not food pyramids!!

16
Pyramid of Energy

• Which level has the most energy AVAILABLE?

17

• TROPHIC LEVELS
• Producers (most energy available)-autotrophs
• Primary consumers-herbivores
• Secondary consumers-small carnivores
• Tertiary consumer-large carnivores
• Energy is given off at every level as waste heat
  by the organisms as they survive.

18
How do organisms obtain nutrients?

• Although energy moves through ecosystems in a
  one-way direction, nutrients are recycled.
• Three basic nutrient cycles are present in all
  ecosystems allowing organisms to obtain needed
  nutrients to function effectively.

19
Nitrogen Cycle

• The atmosphere contains 80 nitrogen gas (N2).
• However, this nitrogen can not be used by most
  living things.
• Bacteria are the only organisms that use nitrogen
  gas directly from the atmosphere.
• They can fix nitrogen for plants to use by
  converting it into ammonia.

N2
DNA and proteins
20
Nitrogen CycleTerminology
YUMMY!
N2

• Nitrogen fixation- nitrogen gas
• in atmosphere converted to ammonia (bacteria in
  soil,
• lightning)
• Nitrification- bacteria converting ammonia to
  nitrate (another form of nitrogen)
• Assimilation- absorption of ammonia and nitrate
  by plants

Nitrogen fixation
Assimilation
NH3
21
Nitrogen Cycle Terminology
N2

• Ammonification- decomposers (bacteria and fungi)
  break down of dead organisms and waste and
  return nitrogen to soil as ammonia.
• Denitrification- conversion of ammonia back to
  nitrogen gas (decomposers).

Denitrification
Ammonification
NH3
22
Nitrogen Cycle
23
Why is the nitrogen cycle important?

• Why is nitrogen important to living things?
• How do plants obtain nitrogen?
• Why are bacteria SO important to the nitrogen
  cycle?
• How do we obtain nitrogen?
• Nitrogen cycle movie with QUIZ

24
Water Cycle

• Driving force is the sun and gravity.
• Consists of the alternation between evaporation
  and precipitation.
• Most water returned to the atmosphere comes from
  evaporation from the oceans.

25
Water Cycle Terminology

• Water vapor- gaseous form of water in atmosphere
• Evaporation- liquid water from bodies of water
  becomes gas returned to atmosphere.
• Transpiration- loss of water by land plants
• Condensation- process which water molecules
  gather in atmosphere change from gas to liquid
  when cooled.
• Precipitation- water falls from atmosphere to
  ground (rain, snow, sleet, or hail)

26
Water Cycle
What is missing here?
27
Why is the water cycle important?

• Water is the most important nonliving (abiotic)
  component of an ecosystem.
• Water essentially determines what organisms we
  find in an ecosystem.
• What is the major difference between the tropical
  rainforest and the desert? Why?

28
Carbon Cycle

• Carbon cycles between the living organisms and
  the non-living components of ecosystem.
• Plants are of great importance to the carbon
  cycle!!--photosynthesis
• Carbon exists in the atmosphere as carbon dioxide
  (CO2)
• Why do living things need carbon?

29
Carbon Cycle
30
Carbon Cycle Terminology

• Photosynthesis- process where sunlight, CO2 and
  H2O is used to make carbs.
• CO2 H2O sunlight (energy) ? glucose (carb)
  O2
• Respiration- process by which animals use carbs,
  taking in O2 given off by plants and give off
  CO2
• THE OPPOSITE OF PHOTOSYNTHESIS!
• glucose (carb) O2 ? CO2 H2O energy to live
• Decompositionbreakdown of dead organisms and
  waste, returning carbon to the soil and
  atmosphere
• Fossil fuels- formed by pressure applied to dead
  organisms that are buried in sediment. They are
  carbon and release CO2 when burned.
• Combustion- burning of fossil fuels
• Carbon cycle video with QUIZ

31
Why is the carbon cycle important?

• Organic macromolecules -energy for living
  organisms (carbohydrates), cell membranes
  (lipids), DNA/RNA, and proteins.
• Humans in the United States are altering this
  cycle
• Deforestation
• CO2 is a greenhouse gas
• Burning too many fossil fuels releases extra CO2
  into the atmosphere creating global warming due
  to increased greenhouse effect.
• The greenhouse effect is normal. Global warming
  is abnormal amounts of the greenhouse effect.
• Greenhouse effect video clip

32
(No Transcript)
33
How competition effects ecosystems

• Sometimes two species will compete.
• No two species can occupy the exact same niche
  (job) for a long period time.
• Only one species wins. This is called
  competitive exclusion.

34
What if no one wins?

• In some species interactions, neither species
  wins.
• This results in close, long term associations
  within an ecosystem called symbiotic
  relationships.

35
3 Kinds Symbiotic Relationships

• helped
• - harmed
• 0neither
• Parasitism (/-)
• Commensalism (/0)
• Mutualism (/)

36
Evolution and Ecology

• Symbiotic relationships cause species to evolve
  in response to each other.
• Ex) Flowers pollinated by nocturnal moths.
• This is called coevolution.
• Ant and Fungus Symbiosis

37
Changing Ecosystems

• Changes are a natural part of any ecosystem.
• Succession regular development of an ecosystem
  which leads to gradual replacing of species in a
  community by others.
• Succession

38
Ecosystem Stability

• Does succession ever end?
• Climax community
• Stability - ability of an ecosystem to resist
  change when a disturbance occurs.
• Biodiversity tends to promote stability.

39
Ecosystem Stability

• Keystone species- species that are crucial to the
  stability of an ecosystem.
• If members of a keystone species die, then the
  entire ecosystem can collapse.
• i.e. sea otters- keep sea urchins in check, which
  would take over the kelp beds without the otters

40
Ecosystem Stability

• Invasive/introduced species destroy ecosystems.
• They are species that are brought by humans
  accidentally or purposefully from other places
  and take hold
• They multiply unchecked due to lack of predators
  in new place they are moved to.
• Ex Asian longhorn beetle, Zebra mussels

41
SEA LAMPREY
42
Population DynamicsWorld Populaton Clock

• Population-a group of organisms of the same
  species that occupy a given area.
• Living things reproduce.
• If environmental conditions are favorable, then
  the number of individuals in population should
  increase from one generation to next.

43
Biotic Potential

• Under favorable conditions, a species may reach
  its biotic potential.
• Biotic potential- highest reproduction rate
  possible for a species under ideal conditions.
• Ex) Houseflies
• -lay over 100 eggs at once
• -can reproduce at 1 month old
• -after 7 generations,
• one fly 15 billion flies!!!

44
Exponential Growth

• Population grows rapidly to infinitely high
  number.
• Represented by J curve
• This does NOT describe real-life.

biotic potential
45
Logistic Growth

• Real populations can only grow exponentially for
  short spans.
• Environmental resistance limits size of a
  population.
• Logistic curve- real population growth looks like
  this and isS curve

46
Carrying Capacity

• Population grows slowly, increases, levels off.
• Carrying capacity- total of individuals that
  can be supported by the environment in a
  particular area
• Earth has 6.6 billion peoplehow many more can it
  support?
• Population Crash

47
Population Size- Growth Rate

• Birth rate- individuals born
• Death rate- individuals die
• Immigration- individuals move in
• Emigration- individuals move out
• If
• BR I DR E EQUILIBRIUM
• BR I gt DR E INCREASING
• BR I lt DR E DECREASING
• Population growth video clip

48
Factors Affect Growth Rate Size of Population

• Environmental resistance- limiting factors stop
  population from reaching biotic potential
• Population density -the number of individuals in
  a population for a certain area.

49
Types of limiting factors

• Density independent factors- dont depend on the
  density of individuals
• i.e.) usually abiotic- natural disasters,
  pollution

50
Types of limiting factors

• Density dependent factors factors that affect a
  population as it increases in density
• i.e.) Disease (flu/colds winter)
• Predation
• Competition
• interspecific ( between different
  species)
• intraspecific ( within same species)

2.) Density dependent- affect population as
a result of of individuals
Ex) disease, predation,
competition
51
Problems with Overpopulation

• Humans, more than anything else, are affecting
  the stability of Earth.
• 1.) Decrease in food supply
• -over fishing
• -agricultural land/residential
• 2.) Energy shortage-
• - renewable/nonrenewable resources
• 3.) Destruction natural resources
• -topsoil, groundwater, species
• 4.) Pollution
• -water
• -air (acid rain, ozone depletion due to CFCs
  in aerosol cans, global warming due to
• burning and deforestation?CO2
• -production of tons of solid waste

52

• Ozone Shield
• Ozone (O3) in the atmosphere absorbs harmful UV
  light.
• Since the late 70s, scientists have discovered
  that the ozone layer over Antarctica has
  decreased by as much as 60
• Ozone Good Up High, Bad Near By
• Human inputs?
• chlorofluorocarbons(CFCs)
• Problems?
• UV light is a mutagen, which can cause skin
  cancer
• Cataracts

53
Biomes

• Biomes are groups of terrestrial ecosystems that
  have the same climate and dominant communities.
• 3 types of biomes
• Temperate seasonal
• Tropical by equator and hot year round
• Arctic far from equator and cold year round
• You have forests, deserts and grasslands in these
  different areas

54
Biomes

• Biomes
• Temperate forests (deciduous)
• Grasslands
• Tropical forest
• Tropical desert
• Tropical grassland (called savannahs)
• Arctic forests (taiga)
• Arctic grasslands (tundra)

55
Aquatic Lifezones

• Aquatic lifezones are aquatic ecosystems.
• Freshwater or saltwater.
• Freshwater
• Wetlands are very important ecosystems.
• Bogs, swamps or marshes.
• Rivers
• Ponds
• Estuaries (wetlands where river meets sea)
• Mangrove swamps
• Saltwater (Marine)
• Coral Reefs
• Intertidal zone
• Open ocean
• Biomes-22min