introduction to ecology & thehome.mca.k12.pa.us/~mudrya/apbio/ecology/chap50.pdfliving in a...
TRANSCRIPT
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INTRODUCTION TO ECOLOGY & THE
BIOSPHERECHAPTER 50
Key Concepts:
� Ecology integrates all areas of biological research and informs environmental decision making.
� Interactions between organisms and the environment limit the distribution of species.
� Aquatic biomes are diverse and dynamic systems that cover most of Earth.
� The structure and distribution of terrestrial biomes are controlled by climate and disturbance.
ECOLOGY� Study of the interactions between organisms & the
environment� Subfields:
� Organismal ecology - concerned w/ an organisms’ structure & physiology meet challenges of the environment
� Population ecology - concentrate on factors that affect how many individuals of a species live in an area
� Community ecology - deals w/ the array of interacting species in a community
� Ecosystem ecology - emphasis on energy flow & chemical cycling among living & non living factors
� Landscape ecology - deals w/ the array of ecosystem & how they are arranged in geographic regions
Levels of Ecology
� Biosphere - sum of all the planet’s ecosystems� Ecosystems - all nonliving & living components of
the environment� Communities - all the organisms of all the species
that inhabit a particular area� Populations - group of individuals of the same species
living in a particular area
Organisms & the Environment
� Biotic factors - all the living components of the environment
� Abiotic factors -nonliving components; chemical & physical factors� Temperature, sunlight,
precipitation, pH, salinity
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Factors Affecting the Distribution of Organisms
� Biogeography - study of the past & present distribution of individual species
� Dispersal - distribution of organisms within geographic population boundaries
� Continental drift & barriers contribute to the distinct floral & fauna found in Earth’s major regions
Transplanted Species� Some organisms can
survive in new areas but cannot reproduce
� Cannot determine the success of a transplant until at least one life cycle is completed
� If successful: then potential range of species is larger than its actual range
� If unsuccessful: species cannot survive & reproduce due to biotic or abiotic factors
Examples of Failed Introduced Species
� African Honey Bees - introduced in Brazil to produce more honey; accidentally escaped & have gradually moved into Southern western U.S.; killed 10 people
� Zebra Mussel - native to Caspian Sea in Asia; discovered in Detroit lakes; clogged water intakes for cities; affect food chain by clearing water & allowing bottom rooted plants to increase; feed on phytoplankton which affected zooplankton population
Biotic Factors Affecting Distribution
� Negative interactions with other organisms through disease, predation & competition
� Elimination of a species that introduce species depends upon
Abiotic Factors Affecting Distribution of Species
� Temperature - effects biological processes & inability of most organisms to regulate body temperature
� Water - aquatic organisms must maintain osmotic balance with environment; terrestrial organisms need to prevent dessication
� Sunlight - competition for light by organisms in shade; in aquatic habitats light intensity determines presence of photosynthetic organisms; photoperiod -lengths of daytime & night time
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� Wind - effects temperature by increasing heat loss due to evaporation & convection; contributes to water loss in organisms; inhibit growth of limbs in plants
� Rocks & Soil - physical structure, pH & mineral composition limits distribution of plants & animals that feed on them; can affect water chemistry
Biomes
� Major types of ecosystems characterized by geographic regions, climate and vegetation
� Aquatic biomes account for largest part of biosphere-freshwater(salt < 1%) or marine (salt > 3%)
Freshwater Biomes� Ponds & lakes (standing water), rivers & streams
(moving water)� Littoral zone - shallow areas along shoreline;
light penetration; rooted and floating plants & phytoplankton
� Limnetic zone - well lit open surface waters; primarily algae & phytoplankton; zooplankton, fish, reptiles, & birds; divided into photic (light penetration) and aphotic ( no light)
� Thermocline – area where warm upper layers separate from cold deeper layers.
� Profundal zone - decrease in light penetration� Bentic zone - bottom; no light; detritus
LAKE ZONATION Classification of Lakes
� Oligotrophic� Deep
� Poor nutrient content
� Sparse phytoplankton
� Rocky hard bottoms
� Clear water
� Oxygen rich
� Diverse fish & invertebrate populations
� Eutrophic� Shallow
� Nutrient content high
� Productive phytoplankton
� Silt, clay bottoms
� Murky water
� Oxygen poor
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� Mesotrophic - moderate nutrients & phytoplankton productivity
� Oligotrophic lakes can become mesotrohic & eventually eutrophic - eutrophication
� Rate increase by increase in nitrogen & phosphorous from fertilizer & detergents
� Causes population explosion of algae and detritus and in turn decrease in oxygen
Streams & Rivers
� Nutrient content determined by terrain & vegetation through which water flows
� Leave litter adds organic nutrients while weathering rock contributes to inorganic nutrients
� Turbulence oxygenate water
Wetlands� Area covered with water that supports aquatic
plants� Specially adapted plants called hydrophytes -
grow in water or soil that is periodically anaerobic due to presence of water
� 3 types -swamps, marshes & bogs; determined by topography� Basin wetlands - develop in shallow basins, ranging from
upland depressions to filled-in lakes & pond� Riverine wetlands - develop along shallow & periodically
flooded banks of rivers & streams� Fringe wetlands - occur along the coasts of large lakes & seas
where water flows back & forth rising lake levels or tidal action
Basin Wetland Riverine Wetland
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Fringe Wetland � Riches of biomes
� Support diverse population of organisms
� Provide water storage basins that reduce intensity of flooding
� Improve water quality by filtering pollutants
Estuaries
� Area where freshwater merges with ocean� Bordered by coastal wetlands called mudflats & salt
marshes� Salinity varies spatially & on time of day (tides)� One of most productive biomes due to being enriched
by nutrients of river� Producers - grasses, algae, phytoplankton� Consumers - invertebrates, fish & birds
Zonation in Marine Communties
� Intertidal - area where land meets water
� Alternately submerged & exposed due to tide cycles
� Organisms subjected to availability of saltwater, temperature changes & wave action
� Attach to hard surfaces, borrow in sand
OCEAN ZONATION
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Horizontal Zonation
� Neritic Zone - shallow regions over continental shelf� Contains coral reefs in tropical waters
� Dominated by coral - external calcium carbonate skeleton
� “bleaching” due to high temps
� Oceanic Zone - area extending to continental slope
Vertical Zonation
� Pelagic Zone - open water at any depth� Photic zone
� Aphotic zone
� Benthic zone
� Abyssal zone - area of deep benthic communities; adapted to cold & absence of light; deep sea hydrothermal vents