APES Lesson 33 - Ecosystems - science-b

Report
AP Environmental
Science
Mr. Grant
Lesson 33
Ecosystems
© 2011 Pearson Education, Inc.
Objectives:
• Define the terms gross primary production and net
primary production.
• Define ecosystems and evaluate how living and nonliving
entities interact in ecosystem-level ecology.
• Outline the fundamentals of landscape ecology, GIS, and
ecological modeling.
• Assess ecosystems services and how they benefit our
lives.
© 2011 Pearson Education, Inc.
Define the terms gross primary production and
net primary production.
Gross Primary Production: The energy that results
when autotrophs convert solar energy (sunlight) to energy
of chemical bods in sugars through photosynthesis.
Autotrophs use a portion of this production to power their
own metabolism.
Net Primary Production: The energy or biomass that
remains in an ecosystem after autotrophs have
metabolized enough for their own maintenance through
cellular respiration. Net primary production is the energy
or biomass available for consumption by heterotrophs.
© 2011 Pearson Education, Inc.
Define ecosystems and evaluate how living and
nonliving entities interact in ecosystem-level ecology.
• Ecosystems consist of all organisms and nonliving entities that
occur and interact in a particular area at the same time.
• Energy flows in one direction through ecosystems, whereas
matter is recycled.
• Energy is converted to biomass and ecosystems vary in their
productivity.
• Input of nutrients can boost productivity, but an excess of
nutrients can alter ecosystems in ways that cause severe
ecological and economic consequences.
© 2011 Pearson Education, Inc.
Ecosystems
• Ecosystem = all organisms and nonliving entities that
occur and interact in a particular area at the same time
- It includes abiotic and biotic components
• Biological entities are tightly intertwined with chemical
and physical entities
- Through interactions and feedback loops
• Ecosystems receive, process and transform inputs of
energy
- While cycling and recycling matter
- Outputs produced include heat, water, wastes
© 2011 Pearson Education, Inc.
Systems of interacting entities in ecosystems
• Energy from the sun flows in one direction
- Arriving as radiation and leaving as heat
• Matter is recycled within ecosystem
- Through food-web relationships and decomposition
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Energy is converted to biomass
• Primary production = conversion of solar energy to
chemical energy in sugars by autotrophs
• Gross primary production (GPP) = assimilation of
energy by autotrophs
• Net primary production (NPP) = energy remaining
after respiration which is used to generate biomass
- Available for consumption by heterotrophs
• Secondary production = biomass generated by
heterotrophs from consuming autotrophs
• Productivity = rate at which ecosystems generate
biomass
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Net primary productivity of ecosystems
High net primary productivity = ecosystems whose plants rapidly convert solar
energy to biomass
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NPP variation causes global geographic
patterns
NPP increases with temperature and precipitation on land, and with light and nutrients
in aquatic ecosystems
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Nutrients can limit productivity
• Nutrients = elements and compounds required for
survival that are consumed by organisms
• Macronutrients = required in larger amounts
- Nitrogen, carbon, phosphorus
• Micronutrients = nutrients needed in smaller amounts
• Nutrients stimulate plant production
- Nitrogen and phosphorus are important for plant and
algal growth
Dramatic growth of algae in
water treated with phosphate
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Nutrient runoff is devastating aquatic
systems
• Nitrogen is the more important limiting factor for
primary productivity
- In coastal ocean waters
- Iron is an effective nutrient for open ocean waters
• Satellite imagery gives scientists an improved view of
productivity at regional and global scales
Phytoplankton blooms off the
Louisiana coast
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Worldwide marine dead zones
• Over 400 dead zones occur globally
- Most are off the coasts of Europe and the U.S.
- Mostly due to farm, city and industrial pollution
- Some are seasonal, others are permanent
• Fisheries and ecosystems are devastated
- Causing over $2 billion/year in lost harvests
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Ecosystems interact spatially
• Ecosystems vary greatly in size
- From a puddle of water to a bay, lake or forest
• The term “ecosystem” is most often applied to selfcontained systems of moderate geographic extent
• Adjacent ecosystems may share components and interact
- I.e. prairie and forests interact where they converge
• Ecotones = transitional zones between two ecosystems
- Elements of each ecosystem mix
© 2011 Pearson Education, Inc.
Outline the fundamentals of landscape
ecology.
• Landscape ecology studies how landscape structure influences
organisms.
• Landscapes consist of patches spatially arrayed in a mosaic.
Organisms dependent on certain types of patches may occur in
metapopulations.
• Remote sensing technology and GIS are assisting the use of
landscape ecology in conservation and regional planning.
© 2011 Pearson Education, Inc.
Remote sensing applies landscape ecology
• Remote sensing allows scientists
to take a landscape perspective
• Geographic information system
(GIS) = computer software used in
landscape ecology research
- Analyzes how elements of a
landscape are arranged
- Helps in planning and land-use
decisions
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Modeling helps us understand systems
• A model = a simplified representation of a complex
natural process
- Helps us understand the process and make predictions
• Ecological modeling = constructs and tests models
- To explain and predict how ecological systems work
• Researchers gather data and form a hypothesis about
relationships
- Models predict how the system will behave
- New data refine and increase the model’s accuracy
© 2011 Pearson Education, Inc.
Ecological modeling
Ecological modeling resembles the scientific method
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Assess Ecosystem services and how they
benefit our lives.
• Ecosystems provide “goods” we know as natural resources.
• Ecological processes naturally provide services that we can
depend on for everyday living.
© 2011 Pearson Education, Inc.
Ecosystems provide vital services
• Human society depends on healthy, functioning
ecosystems
- They provide goods and services we need to survive
• Ecosystem services = provided by the planet’s systems
- Soil formation, water and air purification, pollination
- Breakdown of some pollutants and waste
- Quality of life issues (inspiration, spiritual renewal)
- Nutrient cycling
© 2011 Pearson Education, Inc.
Ecosystem goods and services
© 2011 Pearson Education, Inc.

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