Title: Ecosystems: What Are They and How Do They Work?
1Chapter 3
- Ecosystems What Are They and How Do They Work?
2THE NATURE OF ECOLOGY
- Ecology is a study of connections in nature.
- How organisms interact with one another and with
their nonliving environment.
Figure 3-2
3Organisms and Species
- Organisms, the different forms of life on earth,
can be classified into different species based on
certain characteristics.
Figure 3-3
4Classification of Life
- Domain
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
5Connect Populations, Communities, and Ecosystems
- Members of a species interact in groups called
populations. - Populations of different species living and
interacting in an area form a community. - A community interacting with its physical
environment of matter and energy is an ecosystem.
6Populations
- A population is a group of interacting
individuals of the same species occupying a
specific area. - The space an individual or population normally
occupies is its habitat.
Figure 3-4
7Populations
- Genetic diversity
- In most natural populations individuals vary
slightly in their genetic makeup.
Figure 3-5
8Life on Earth is sustained by
- Troposphere 78 Nitrogen and 21 Oxygen
- Stratosphere GOOD ozone (O3)
- Lithosphere nonrenewable resources and minerals
9Life on earth is sustained by
- Solar energy (low quality), the cycling of matter
(fixed amount), and gravity (maintain atmosphere)
sustain the earths life. - Can energy be recycled?
Figure 3-7
10Solar Energy and the Earth
What does solar energy do that is important for
life on Earth?
11 Greenhouse Effect
- solar radiation enters as visible light and
degraded to infrared radiation - encounters the greenhouse gases in the
troposphere. - The greenhouse gases absorb the IR waves and then
emit more IR waves (even longer wavelengths) - this speeds up the air molecules (gain KE) and
this heats the troposphere and earths surface.
12What are ECOSYSTEM COMPONENTS?
- Life exists on land systems called biomes and in
freshwater and ocean aquatic life zones.
Figure 3-9
13Nonliving and Living Components of Ecosystems
- Ecosystems consist of nonliving (abiotic) and
living (biotic) components.
Figure 3-10
14Factors That Limit Population Growth
- Range of Tolerance and Availability of matter and
energy resources (limiting factors) can limit the
number of organisms in a population. - Population controlsustainability
Figure 3-11
15Biotic Factors in an Ecosystem
- Most PRODUCERS capture sunlight to produce
carbohydrates by photosynthesis - Autotrophs (plants, algae, phytoplankton,
plant-like protists)
16Photosynthesis A Closer Look
- Chlorophyll molecules in the chloroplasts of
plant cells absorb solar energy. - This initiates a complex series of chemical
reactions in which carbon dioxide and water are
converted to sugars and oxygen.
Figure 3-A
17Producers cont.
- Chemosynthesis
- Some organisms such as deep ocean bacteria draw
energy from hydrothermal vents and produce
carbohydrates from hydrogen sulfide (H2S) gas .
18Consumers Eating and Recycling to Survive
- Consumers (heterotrophs) get their food by eating
or breaking down all or parts of other organisms
or their remains. - Herbivores
- Primary consumers that eat producers
- Carnivores
- Primary consumers eat primary consumers
- Third and higher level consumers carnivores that
eat carnivores. - Omnivores
- Feed on both plant and animals.
19Decomposers and Detrivores-consumers TOO!
- Decomposers Recycle nutrients in ecosystems.
- Detrivores Insects or other scavengers that feed
on wastes or dead bodies.
Figure 3-13
20Aerobic (with Oxygen) and Anaerobic Respiration
Getting Energy for Survival
- breaking down carbohydrates and other organic
compounds to obtain the energy - This is usually done through aerobic respiration.
- The opposite of photosynthesis
21Cont.
- Anaerobic respiration or fermentation
- Some decomposers get energy by breaking down
glucose without oxygen. - The end products vary based on the chemical
reaction - Methane gas
- Ethyl alcohol
- Acetic acid
- Hydrogen sulfide
22Two Secrets of Survival Energy Flow and Matter
Recycle
- An ecosystem survives by a combination of energy
flow and matter recycling.
Figure 3-14
23Biodiversity maintains Ecosystems
- We are losing biodiversity due to HIPPO
- H for habitat destruction and
- degradation-leading cause
- I for invasive species- 2nd leading cause
- P for pollution leading to global climate change.
- P for human population growth that leads to
resource consumption - O for overexploitation- overhunting and
overconsumption - Who is Aldo Leopold?
24ENERGY FLOW IN ECOSYSTEMS
- Food chains and webs show how eaters, the eaten,
and the decomposed are connected to one another
in an ecosystem. - Energy flows in 1 Direction!
Figure 3-17
25- Interconnected food chains make up a complicated
food web. - Which trophic level would there be more
organisms, 1st or 4th? Why?
Figure 3-18
26Energy Flow in an Ecosystem Losing Energy in
Food Chains and Webs
- In accordance with the 2nd law of thermodynamics,
there is a decrease in the amount of energy
available to each succeeding organism in a food
chain or web.
2710 RULE in energy flow
- Ecological efficiency percentage of useable
energy transferred as biomass from one trophic
level to the next. - Where does the energy go?
Figure 3-19
28Due to the high need for producers to maintain
our growing population you must consider
- Gross primary production (GPP)
- Rate at which an ecosystems producers convert
solar energy into chemical energy as biomass.
Figure 3-20
29AND Net Primary Production (NPP)
- NPP GPP R
- Rate at which producers use photosynthesis to
store energy minus the rate at which they use
some of this energy through respiration (R).
Figure 3-21
30Why does GPP and NPP matter?
- As humans take up more land and degrade more
forest ecosystems, we lower the earths possible
GPP and NPP. - Estimates say that humans and domesticated
animals take up 98 of earths biomass and
wildlife only 2. OUT OF BALANCE!
31- What are natures three most productive and three
least productive systems?
Figure 3-22
32MATTER CYCLING IN ECOSYSTEMS
- Nutrient Cycles Global Recycling
- Global Cycles recycle nutrients through the
earths air, land, water, and living organisms. - Nutrients are the elements and compounds that
organisms need to live, grow, and reproduce. - Biogeochemical cycles move these substances
through air, water, soil, rock and living
organisms.
33The Water Cycle
Figure 3-26
34Water Unique Properties
- There are strong forces of attraction between
molecules of water. - Water exists as a liquid over a wide temperature
range. - Liquid water changes temperature slowly.
- It takes a large amount of energy for water to
evaporate. - Liquid water can dissolve a variety of compounds.
- Water expands when it freezes.
35Effects of Human Activities on Water Cycle
- We alter the water cycle by
- Withdrawing large amounts of freshwater.
- Clearing vegetation and eroding soils.
- Polluting surface and underground water.
- Contributing to climate change.
36The Carbon CyclePart of Natures Thermostat
- PS and CR recycle
- Ocean stores (dissolved Carbon dioxide)
- Shells of marine life store (Calcium carbonate)
- Limestone stores
- Fossil Fuels store until BURNED
Figure 3-27
37Effects of Human Activities on Carbon Cycle
- We alter the carbon cycle by adding excess CO2 to
the atmosphere through - Burning fossil fuels.
- Clearing vegetation faster than it is replaced.
Figure 3-28
38The Nitrogen Cycle Bacteria in Action
Figure 3-29
39Explanation of the chart
- 2 processes FIX atmospheric nitrogen into a
usable form - Lightning
- Nitrogen-fixing bacteria in soil
- NITROGEN FIXATION
- FIX N2?NH3 (ammonia)?NH4 (ammonium) that can be
taken up by plants - NITRIFICATION
- NH3 and NH4 is converted to nitrite,NO2- TOXIC
TO PLANTS and then nitrate, NO3- GOOD FOR PLANTS
AND ANIMALS WHO EAT PLANTS
40Cont.
- Plants and animals put nitrogen back into
environment through wastes and when they die. - AMMONIFICATION is when decomposer bacteria
convert this organic material from their death
into simpler nitrogen-containing inorganic
compounds like ammonia (NH3) and ammonium (NH4). - DENITRIFICATION is when specialized bacteria in
wet areas convert ammonia and ammonium back into
nitrogen gas and nitrous oxide gas (both GHGs).
41Effects of Human Activities on the Nitrogen Cycle
- We alter the nitrogen cycle by
- Adding gases (NO, nitric oxide, from burning
fuels) that contribute to acid rain. - Adding N2O, nitrous oxide to the atmosphere
through fertilizers added to crops which can warm
the atmosphere and deplete ozone. - Contaminating ground water from nitrate ions in
inorganic fertilizers disrupting aquatic life. - Releasing nitrogen into the troposphere through
deforestation.
42The Phosphorous Cycle- doesnt enter AIR
Figure 3-31
43Explanation of chart
- Phosphorus is found as phosphate ions (PO43-) in
rock and soil. As water runs over rocks the
phosphates mix into the water and ends up in the
ocean where it settles to the ocean floor. - Plants take phosphates directly from the soil or
water and build macromolecules with it. - Animals take in plants and excrete extra
phosphorus in urine. - Phosphorus is often a LIMITING FACTOR for plants
because there is little in soil (unless added
from fertilizer) and is only slightly soluble in
water.
44Effects of Human Activities on the Phosphorous
Cycle
- We remove large amounts of phosphate from the
earth to make fertilizer. - We reduce phosphorous in tropical soils by
clearing forests. - We add excess phosphates to aquatic systems from
runoff of animal wastes and fertilizers.
45The Sulfur Cycle
Figure 3-32
46Explanation of chart
- Found as sulfate (SO42-)in rocks and minerals and
salts buried deep under ocean sediments - Released from volcanoes as hydrogen gas (H2S)
and sulfur dioxide (SO2) - Sulfate salts like ammonium sulfate are released
by sea spray, dust storms, and forest fires - Plants absorb sulfate ions and incorporate them
into their macromolecules - Marine bacteria produce dimethyl sulfide (DMS)
which begins condensation thus can affect climate - DMS is converted to SO2 and SO3 and then to
sulfuric acid (H2SO4) ACID RAIN
47Effects of Human Activities on the Sulfur Cycle
- We add sulfur dioxide to the atmosphere by
- Burning coal and oil
- Refining sulfur containing petroleum.
- Convert sulfur-containing metallic ores into free
metals such as copper, lead, and zinc releasing
sulfur dioxide into the environment.
48What is the Gaia Hypothesis?
49Chapter 7
50What are important characteristics of a community?
- Species diversity- the number of different
species it contains (species richness) combined
with the abundance of individuals within each of
those species (species evenness) - Niche structure- of niches, differences in
niches, and how individuals in different niches
interact - Geographical location- closer to equator more
diversity usually due to constant conditions near
tropics
51What are the types of species in a community?
- Native species- normally live and thrive in a
particular community - Nonnative species, invasive and alien species are
introduced into a community. - NOT ALWAYS BAD (chickens, cattle) but CAN BE
(African killer bee intended to help honey
production increase)
52- Indicator species- serve as early warnings of
damage to a community - Example trout for water quality because they
need clean water with lots of dissolved oxygen - Ex. Birds and butterflies greatly affected by
habitat loss and chemical exposure - Ex. Amphibians GOOD INDICATOR SPECIES
53Why are Amphibians Vanishing?
- Because they live part of life in water and part
on land so tell about water, soil, and air
quality. - Affected by pollution (pesticides), habitat
loss, drought, increase UV light, climate change,
overhunting
Figure 7-3
54- Keystone species- a species that greatly affects
other species in the community. - Ex. Pollinators like bees and butterflies
- Ex. Top predators like wolves, lions, alligators,
some sharks - Foundation species- play a major role in shaping
communities by creating and enhancing their
habitats in ways that benefit other species. - Ex. Elephants that push over trees and allow
smaller grasses to grow that allow grazers like
antelope to eat. - Ex. Bats and birds that move seeds around by
eating and dropping them in feces to re-grow a
forest that has been depleted.
55What types of interactions do species have?
- Interspecific competition- ability of one species
to become more efficient in acquiring resources
than another. POPULATION SIZE CONTROL - 1. Resource partitioning- adaptations evolved
that reduce competition that allow species to
share resources by evolving specialized traits. - Example hawks feed during day, owls at night
- Ex. Lions take larger prey, leopards take smaller
56Resource Partitioning
- Each species minimizes competition with the
others for food by spending at least half its
feeding time in a distinct portion of the spruce
tree and by consuming somewhat different insect
species.
Figure 7-7
57Niche Specialization
- Niches become separated to avoid competition for
resources.
Figure 7-6
58Interactions of species cont.
- Predation- predators feed on prey. POPULATION
CONTROL AND NATURAL SELECTION (makes population
stronger) - Ex. Lions feed on zebras predator-prey
relationship - Parasitism- parasite benefits by living in or on
the host who is harmed. POPULATION CONTROL - Tapeworms, ticks, fleas, mistletoe, cowbirds
- Mutualism- both species benefit
- Honeybees, caterpillars, butterflies pollinate
flowers and feed on nectar - Clownfish and sea anemone
- Fungus with plant roots that makes Mycorrhizae.
Fungus feeds on plant roots but plant has more
roots for water uptake. - Commensalism- benefits one species but has little
to no effect on the other. - Birds and trees- birds have habitat
- Orchids that grow on trees in tropics get more
light and stable place to grow but dont affect
tree.
59PREDATION
- Some prey escape their predators or have outer
protection, some are camouflaged, and some use
chemicals to repel predators.
Figure 7-8
60Mutualism Win-Win Relationship
- Two species can interact in ways that benefit
both of them.
Figure 7-9
61Commensalism Using without Harming
- Some species interact in a way that helps one
species but has little or no effect on the other.
Figure 7-10
62Ecological succession the gradual change in
species composition of a given area
- Primary succession the gradual establishment of
biotic communities in lifeless areas where there
is no soil or sediment. - No soil present, exposed rock, lava, concrete
- Lichens or mosses attach to rock and break them
down by releasing acids, and catch soil particles
floating in wind (millions of years to produce
fertile soil)
63- Secondary succession series of communities
develop in places containing soil or sediment. - Begins in an area where the community has been
disturbed or destroyed (forests burned, farm
abandoned, heavily polluted streams
64How do living systems maintain stability?
- Adaptations in response to changing environments
(not within an individuals lifetime but over
generations) - Persistence- ability of a living system to resist
being disturbed - Constancy- ability of a living system to keep its
numbers within the limits imposed by natural
resources - Resilience- ability of living system to bounce
back and repair damage after a disturbance that
it not too drastic - Diversity
65Function within the 4 scientific principles of
sustainability
- Depend on solar energy
- Participate in chemical cycling
- Have a diversity of types and species
- Populations are controlled by interactions among
their species