1. AP Environmental Science
Mr. Grant
Lesson 33
Ecosystems

2. 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.

3. 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.

4. 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.

5. 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 5 5

6. 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 6 6

7. 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 7 7

8. Net primary productivity of ecosystems
High net primary productivity = ecosystems whose plants rapidly convert solar energy to biomass

9. NPP variation causes global geographic patterns
NPP increases with temperature and precipitation on land, and with light and nutrients in aquatic ecosystems

10. 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 10 10

11. 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

12. 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

13. 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 self- contained 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 13 13

14. 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.

15. 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 15 15

16. 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

17. Ecological modeling
Ecological modeling resembles the scientific method

18. 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.

19. 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

20. Ecosystem goods and services