Transcript AP Bio Ecology

AP Bio Ecology
Chapter 50
Ecology is the study of the interactions between organisms and the environment.
Ecological Research ranges from adaptations of
organisms to dynamic ecosystems
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Ecology can be divided into 4 levels of study.
Organismal ecology: is concerned with the behavioral, physiological
and morphological ways in which individual organisms meet challenges
posed by their abiotic environment.
Populations: is the next level of organization, population is a group of
individuals of the same species living in a particular geographical area.
A community: which consists of all organisms that inhabit a particular
area
Ecosystem: includes all the abiotic factors in addition to the
community of species that exist in a certain area.
Ecology provides a scientific context for evaluating
environmental issues
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Much of our current environmental awareness had its beginnings
with Rachel Carson’s 1962 book Silent Spring which pointed out
the use of pesticides such as DDT were causing populations to
decline.
Today acid rain, localized famine aggravated by land misuse and
population growth, the poisoning of soil and streams with toxic
waste, and the growing list of species extinct or endangered
because of habitat destruction are just a few problems that
threaten the home we share with millions of other life forms.
Abiotic factors of the biosphere
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The biosphere is the sum of all the planets ecosystems, or all of
life and where it lives.
Major abiotic factors: Temperature, water, sunlight, wind, rocks
and soil.
Most organisms ultimately get there energy from sunlight, and
must tolerate the ranges of temperature, humidity, salinity, and
light in there environment.
Temperature
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Temperature is an important factor in the distribution of organisms
because of the effects on biological processes and the inability to
regulate body temperature precisely.
For example cells may rupture if the water they contain freezes at
temperatures below 0C and most proteins will denature if
temperature rises above 45C.
The actual internal temperature of an organism is affected by heat
exchange with its environment.
Endotherms are the exception, but even endotherms function best
with in certain environmental temperature ranges that vary from
species to species
Water
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Water is essential to life, but its availability varies dramatically
among habitats.
Freshwater and marine organisms live submerged in an aquatic
environment, but face problems with osmolarity.
Organisms in terrestrial environments encounter a nearly
constant threat of desiccation, and their environment has been
shaped by the requirements for obtaining and conserving
adequate supplies of water.
The unique properties of water have effects on organisms an
their environments (cohesive/adhesive, high specific heat, etc)
Sunlight
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Sunlight provides the energy that drives nearly all ecosystems,
although plants and other photosynthetic organisms are the only
ones to use the sunlight directly.
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Light is also important to the development and behavior of the
many plants and animals that are sensitive to photoperiod, the
realtive lengths of daytime and nighttime.
Photoperiod is a more reliable indicator then temperature for
cueing seasonal events, such flowering or migration.
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Wind
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Wind amplifies the effect of environmental temperature on
organisms by increasing heat loss due to evaporation and
convection. It also increases water loss in organisms due to the
increased rate of evaporation. Wind can also inhibit the growth
of limbs on trees on the windward side.
Rocks and Minerals
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Rocks and soil: The physical structure, pH, and mineral
composition of rocks and soil limit the distribution of plants and
other animals that feed on them.
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In streams and rivers the composition of the substrate can affect
water chemistry, which in turn influences the resident plants and
animals. In marine environments the structure of substrates in
the intertidal zone on the sea floors determines the types of
organisms that can attach or burrow in those habitats.
Continued
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Periodic Disturbances: Catastrophic disturbances such as fire,
hurricanes, tornadoes, and volcanic eruptions can devastate
biological communities.
After the disturbance the area is repopulated by the survivors,
but the structure of the community is changes during the
rebound.
Some periodic disturbances such as volcanic eruptions, are so
infrequent and unpredictable that organisms have no
evolutionary adaptations to them.
Fire on the other hand recurs frequently in some communities
and some communities require fire to maintain them.
Biome vs. Ecosystem
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Biome: refers to the major types of
ecosystems.
Ecosystem: includes all the biotic and abiotic
factors in a given area.
Biosphere: The global ecosystem. It is the
sum of all the planet’s ecosystems, it includes
the atmosphere and below ground caves.
EC
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I contain a large amount of H2O
I am considered mesotrophic
There are slot sizes fishermen have to abide by before
they take fish from me.
I have a lot of Stizostedion vitreum vitreum in me.
I was in the news paper a lot last spring and summer
I am the fifth largest of my kind in MN
Native Americans can fish me year around with few
restrictions
Aquatic Biomes occupy the largest
part of biosphere
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Ecologists distinguish between fresh water biomes and marine biomes.
The evaporation of seawater provides most of the planets precipitation.
Marine algae and photosynthetic bacteria supply a substantial portion of
the worlds oxygen.
Aquatic Biomes
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Lakes: Oligotrophic, Eutrophic, Mesotrophic
Rivers and Streams
Ponds
Wetlands
Estuaries
Marine biomes: Intertidal zones, coral reefs,
benthos, and abyssal zones.
Vertical Stratification of Aquatic
Biomes Lakes
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Many aquatic biomes exhibit vertical stratification of physical and
chemical variables. Light is absorbed by both the water itself and the
microorganisms in it.
Photic Zone- where light is sufficient for photosynthesis.
Aphotic Zone- Where little light penetrates.
At the bottom of all aquatic biomes a substrate called the benthic zone,
made up of sand and organic and inorganic sediments. Occupied by
organisms collectively called benthos, there main food source is called
detritus.
Fresh Water Biomes
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Two types of fresh water biomes; standing bodies of water which
include lakes and ponds, and moving bodies of water which
include rivers and streams.
littoral zone: the shallow waters close to the shore rooted and
floating aquatic plants flourish here.
limnetic zone: The well-lit, open surface, farther from shore
occupied by a variety of phytoplankton consisting of algae,
cyanobacteria.
These organisms photosynthesize and reproduce at a high rate
during the spring and summer.
Continued
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Zooplankton, mostly rotifers and small crustaceans, graze on the
photoplankton. The zooplankton are then consumed by small fish,
which in turn are eaten by larger fish, semi aquatic snakes, turtles
and fish eating birds.
Most of the small organisms are short lived and their remains sink
into a deep aphotic region called the profundal zone, and down to
the benthic zone.
Microbes in the profundal zone and benthic zone use oxygen for
cellular respiration as they decompose the detritus.
Lakes are often classified according to there production of organic
matter.
Classification of lakes
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Oligotrophic lakes are deep and nutrient poor, the
photoplankton in the limnetic zone are not very productive.
Eutrophic lakes, in contrast are usually shallower and their
nutrient concentration is usually high. As a result
photoplankton are very productive and thw waters a re
frequently murky.
Mesotrophic lakes are in the middle of Oligotrophic and
Eutrophic.
Over long periods of time oligtrophic lakes become Eutrophic
lakes.
Streams and river are bodies of water moving in one
direction constantly.
Turn over
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A stratum of rapid temperature change called a thermocline separates
a more uniformly warm upper layer from a more uniformly lower cold
layer in lakes and oceans.
Terrestrial Biomes
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Based mainly on regional variations in climate.
Tropical forests
Savanna
Desert
Chaparral
Temperate Grasslands
Tundra
Climate and the Distribution of
Organisms
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The abiotic factors just described have a direct effect on the
biology of organisms.
Four factors: Temperature, water, light, and wind are the major
components of the climate.
Biome refers to major types of ecosystems found in a given area.
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USE AP CD AND FIGURE OUT THE DIFFERENT BIOMES
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Global Climate Patterns
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Earth’s global climate patterns are largely determined by the input of
solar energy and the planets movement through space.
The planet is tilted on its axis by 23.5 degrees relative to its plane of
orbit around the sun, its tilt causes seasonal variation in the intensity of
solar radiation.
The angle of solar radiation changes from day to day as Earth revolves
around the sun.
Only the tropic receives sunlight from directly overhead. As a result, the
tropics experience the greatest annual input and least seasonal
variation in solar radiation of any region on Earth.
Local and Seasonal Effects on
Climate.
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Ocean currents effect climates along coasts of continents by heating or
cooling overlying air masses, which may then pass across the land.
Evaporation from the ocean is greater then the land, which is why areas
near the coast are generally moister.
Oceans and large bodies of water generally moderate the climates of
the nearby terrestrial environments on a daily bases.
Mountains also have a major effect on the climate.
In the Northern hemisphere south side slopes receive more sunlight
and therefore are warmer and drier.
Deserts commonly occur on the leeward side of a mountain.