Title: The study of the interactions between organisms and the living and nonliving components of their environment.
1Ecology
- The study of the interactions between organisms
and the living and nonliving components of their
environment.
2Table of Contents Ecology
- Levels of Organization slides 3-7
- Organism Ecology (vocabulary) slides 8-9
- Ecosystems and Energy slides 10-17
- Ecosystem Recycling slides 18-20
- Populations slides 21-30
- Succession slides 31-36
- Invasive Species slides 37-41
- Modern Issues slides 42-57
3Levels of Organization
- Biosphere
- The thin layer of the earth that supports life
(as thin as the skin of an apple!)
4Levels of Organization
- Biomes
- Any of the worlds major ecosystems, classified by
predominant vegetation and characterized by
adaptations of organisms to that particular
environment. - Terrestrial Biomes include
- Tropical forests, Savanna, Desert, Chaparral,
Temperate Grassland, Temperate Broadleaf Forest,
Coniferous Forest, Tundra, High Mountains, Polar
Ice - Aquatic Biomes include
- Lakes, Wetlands, Streams and Rivers, Estuaries,
intertidal zones, oceanic pelagic zones, coral
reefs, marine benthic zones
5Levels of Organization
- Ecosystem
- Includes all of the living (biotic) and non
living (abiotic) components within a particular
place. - Biotic Components of a Pond
- includes fish, turtles, plants, algae, insects,
bacteria. - These interact with each other.
- Abiotic Components of a Pond
- water temperature, dissolved oxygen and carbon
dioxide, nitrogen levels, sun light, pH level. - These are necessary for the living organisms to
survive.
6Levels of Organization
- Community
- Includes all of the interacting organisms within
an area. - Population
- Includes all of the members of a species that
live in one place at a time. - Organism
- The individual in a population.
- Represents the simplest level of organization.
- Most studies focus on the individual organism and
how it has adapted to overcome the challenges in
its environment.
7Levels of Organization
8Organism Ecology
- Biotic Factors - living factors that affect an
organism. - Abiotic Factors - non living factors that affect
an organism. - Habitat - where an organism lives
- Environmental Fluctuations
- As the environment changes, an organism must be
able to tolerate those changes otherwise it will
stress and exhibit reduced performance or simply
die.
9Organism Ecology
- Niche
- Way of life or the role of an organism in its
environment. - Bacteria recycle nutrients
- Predators keep prey populations under control
- Plants use CO2 and produce O2 also provide food
for grazers.
10Ecosystems and Energy
11Energy Transfer
- A common characteristic of all living organisms
is they require energy to carry out metabolic
activities. - Producers
- Usually photosynthetic plants (autotrophs)
- Can also be chemosynthetic (certain bacteria)
12Energy Transfer
- Measuring Productivity
- Gross Primary Productivity
- Rate at which producers capture energy
- Energy is used to make sugar which is used for
repairs, for growth or cellular respiration - Biomass
- Organic matter in the ecosystem
- Net Primary Productivity
- Rate at which biomass accumulates in an ecosystem
- NPP is highest in biomes like tropical rain
forests and estuaries
13Energy Transfer
- Consumers are Heterotrophs
- Herbivores - consume producers
- Cows, deer, mice
- Carnivores - eat consumers
- Mountain Lions, bald eagles, snakes
- Omnivores - eat both producers and consumers
- Bears, people
- Detritivores - feed on dead matter
- Vultures, certain beetles
- Decomposers - decay complex molecules of dead
tissue and wastes into simpler molecules - Bacteria, Fungus
14Energy Transfer
- Energy Flow
- Energy in an ecosystem moves from one organism
into another - Trophic Level
- The organisms position in the sequence of energy
transfers - Food Chain
- A single pathway of feeding relationships in an
ecosystem that shows energy transfer - Food Web
- a series of interrelated food chains in an
ecosystem
15Food Chain
16Food Web
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18Ecosystem Recycling
19Ecosystem Recycling
20Ecosystem Recycling
21Ecology
- Populations
- Growth, Carrying Capacity, Variables
22Population Growth
- If resources, such as food, water and habitats,
were unlimited, then a population of organisms
would grow in an exponential fashion.
- Imagine if this growth curve represented
mosquitoes, elephants or people. The earth would
be over-run and all resources would be rapidly
depleted!
23Population Growth
- Fortunately, in nature resources are limited.
- Limited resources slow growth and if you graph
numbers of organisms over time, the graph takes
the shape below.
24Population Carrying Capacity
- Notice the top of the smooth graph is labeled
carrying capacity. - This is the number of organisms that a habitat
can sustain with the available resources. - If the number of organisms exceeds the carrying
capacity, the population can begin to decline.
25Population Curve
- Notice the tail on this graph.
- When resources have been overused or depleted,
the organisms begin to die out.
26Population Carrying Capacity
- What happened to the reindeer on Matthew Island?
- The reindeer overused their resources and
exceeded the islands carrying capacity almost
dying out.
27Population Size Variables
- What other factors affect the size of a
population? - Birth Rates
- Death Rates
- Immigration-the movement of individuals from
other areas. - Emigration-the movement of individuals out of a
population.
28Population Size Variables
- If the arrows represent actual rates, what would
happen to the size of the population circle if
the death rate arrow was cut in half or the
immigration arrow was doubled?
29Population Size Variables
- If the death rate arrow were cut in half or the
immigration arrow was doubled, the population
circle would increase in size.
Population
Death Rate
Birth Rate
Emigration
Immigration
30Population Variables
- In the United States, birth rates, death rates
and emigration rate are low but our immigration
rate is climbing. How is that affecting our
population size?
31Ecology
32Ecological Succession
- Changes in the number and type of organisms in a
community are most apparent after some type of
disturbance to the habitat. - The disturbed area may be colonized by a variety
of new organisms, which are gradually replaced by
other organisms until a stable group of species
persists within the area. - This process is called Ecological Succession.
33Ecological Succession cont.
- One type of ecological succession is called
Primary Succession. - In primary succession, a new piece of new real
estate, such as a volcanic island where soil and
organisms are lacking, is invaded by lichens and
mosses which are usually blown in as spores. - As soil develops, these organisms are overgrown
by grasses, shrubs and trees that are blown in or
brought in by animals. - Eventually, the area is colonized by plants that
become the main form of vegetation. - This process can take hundreds to thousands of
years.
34To the right, the foreground is bare rock covered
with lichens and mosses. The middle ground
contains a small amount of soil with plants. The
background is a stable forest.
Below is an example of rock covered with lichens.
35Ecological Succession
- Secondary succession occurs when an existing
community is cleared by some disturbance such as
fires, glaciation, deforestation, etc. - Under these circumstances the sequence of
colonization can vary but generally weeds and
other opportunistic plants first invade followed
by grasses or shrubs. These can then be replaced
by trees species.
36Secondary succession occurs in areas where plants
were already established but were disturbed. This
sequence represents a once planted field in North
Carolina.
37Ecology
- Invasive Species
- (Non-Native)
38Invasive Species
- After habitat loss and degradation, mostly due to
human activity, the biggest cause of early
organism extinction is the introduction of
harmful invasive species into an ecosystem. - Invasive species have been intentionally and
accidentally introduced in the U.S. for years. - Intentionally introduced species include
- wheat, rice, corn, cattle, poultry.
- Accidentally introduced species include an
estimated 7100 organisms in the U.S. alone
39Invasive Species cont.
- Accidentally introduced species include
- Brown tree snakes, Japanese beetles, African
honeybees, zebra mussels, Formosan Termites,
Burmese pythons, Gypsy moths, etc. - Species like these cost the U.S. public
approximately 261,000 per minute in damage and
control.
40Invasive Species
- These invasive species cause so much damage
because they have no natural predators,
competitors, parasites or pathogens when
introduced into a new environment. - Nonnative species can reduce or wipe-out
populations of many native species, trigger
ecological disruption, cause human health
problems and lead to economic loss.
41Invasive Species
Kudzu Vine
Burmese Python
Formosan Termite
Gypsy Moth Catepillar
42Ecology
- Modern Issues
- (Optional Information)
43Ecology
- Human Population Explosion
- From 2 Billion in 1930 to 6 Billion in 1996
- Projected to reach over 7.8 Billion in 2050
44World Population Projections
45Ecology
- Mass Extinctions
- The last extinction occurred 65 mya probably due
to an asteroid impact. - Currently organisms are going extinct at a rate
unseen since the dinosaurs last died out. - By 2100, it is expected that one fifth of the
current organisms will be extinct. - Why? Habitat destruction, over hunting, the
introduction of predators and disease.
46Mass Extinction 1
- The following mass extinctions were due to
natural causes. - First major extinction (c. 440 mya) Climate
change (relatively severe and sudden global
cooling) seems to have been at work at the first
of these-the end-Ordovician mass extinction that
caused such pronounced change in marine life
(little or no life existed on land at that time).
25 of families lost (a family may consist of a
few to thousands of species).
47Mass Extinctions 2-3
- Second major extinction (c. 370 mya) The next
such event, near the end of the Devonian Period,
may or may not have been the result of global
climate change. 19 of families lost. - Third major Extinction (c. 245 mya) Scenarios
explaining what happened at the greatest mass
extinction event of them all (so far, at least!)
at the end of the Permian Period have been
complex amalgams of climate change perhaps rooted
in plate tectonics movements. Very recently,
however, evidence suggests that a bolide impact
similar to the end-Cretaceous event may have been
the cause. 54 of families lost.
48Mass Extinction 4
- Fourth major extinction (c. 210 mya) The event
at the end of the Triassic Period, shortly after
dinosaurs and mammals had first evolved, also
remains difficult to pin down in terms of precise
causes. 23 of families lost.
49Mass Extinction 5
- Fifth major extinction (c. 65 mya)
- Most famous, perhaps, was the most recent of
these events at the end-Cretaceous. It wiped out
the remaining terrestrial dinosaurs and marine
ammonites, as well as many other species across
the phylogenetic spectrum, in all habitats
sampled from the fossil record. Consensus has
emerged in the past decade that this event was
caused by one (possibly multiple) collisions
between Earth and an extraterrestrial bolide
(probably a comet). 17 of families lost.
50Last Extinction Event
51The Sixth Mass Extinction
- How is the Sixth Extinction different from
previous events? - The current mass extinction is anthropogenic
(caused by humans). - Humans are the direct cause of ecosystem stress
and species destruction in the modern world
through such activities as - Habitat degradation
- Overexploitation of species
- Pollution
- The introduction of invasive species
52Ecology
- Thinning Ozone Layer
- This layer is responsible for protecting life
from UV radiation from the sun. - CFCs in the earths upper atmosphere cause ozone
(O3) to break down into oxygen (O2). - This effect is magnified at the earths poles.
- A 1992 treaty banned CFCs (Chloroflourocarbons)
from use, but long-term persistence of CFCs in
the atmosphere continues to degrade ozone. - Recent evidence suggests ozone degradation is
slowing.
53Total Ozone
54Ozone Hole
55Ecology
- Modern Issues
- Global Warming
- Carbon Dioxide (CO2) produce by humans has
increase the atmospheric CO2 steadily since the
late 1800s.
56Ecology
- Global Warming
- The increase in greenhouse gases (CO2, O3, CH4)
is slowly increasing the average temperature of
the earth. - This is resulting in rising sea level, melting
ice caps, changes in storm patterns and changes
in oceanic current flows. - Environmental knowledge is essential in trying to
stop and reverse destructive human practices.
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