Ecosystems

Standards: SC.912.N.1.1, SC.912.L.17.2, SC.912.L.17.4, SC.912.L.5, SC.912.L.17.8

Textbook: Chapter 3, Chapter sections 6.2, 6.3

ECOSYSTEMS

A. What is biology

1. Big ideas in biology

2. Characteristics of living things

B. Distribution of Life in Aquatic Ecosystems (17.2)

1. Biotic factors

2. Abiotic factors

a. Chemical Factors (pH, Salinity, Oxygen, Nitrogen, Phosphorus, Carbon Dioxide)

b. Geographical Factors (water depth, latitude, temperature, underwater topography, and proximity to land)

C. Changes in Ecosystems over time (17.4)

1. Seasonal changes

2. Climate changes

3. Primary vs. Secondary Succession

4. Natural vs Anthropogenic

D. Reduction of Biodiversity (17.8) (N.1.4)

1. Climate change (limited to biodiversity, population dynamics, and ecosystem contexts)

2. Seasonal Changes

3. Catastrophic events

4. Human Activity (From a reduction of biodiversity perspective and not human impact)

5. Invasive/Nonnative Species

OBJECTIVES

· List the characteristics of living things.

· Explain that different types of organisms exist within aquatic systems due to chemistry, geography, light, depth, salinity, and/or temperature.

· Predict the changes to an ecosystem resulting from seasonal variations, climate changes, and succession

· Identify positive and/or negative consequences that result from a reduction in biodiversity

Vocabulary:

abiotic, biotic, biodiversity, climate, weather, ecosystem, aquatic, benthic, salinity, phytoplankton, zooplankton, photic, aphotic, eutrophication, invasive species, native species, succession, primary succession, secondary succession, pioneer species, climax community

3.1 Intro to global systems

Ecology is the scientific study of interactions among organisms and between organisms and their physical environment.We depend on ecological processes to provide such essentials as food and drinkable water that can be bought and sold or traded. Also, our actions, like those of other animals, can change our environment.

How ecology is studied

Ecologists generally rely on three main approaches, all of which are part of scientific methodology: observation, experimentation, and modeling. Ecologists may use tools ranging from DNA analysis to data gathered from satellites.

A biotic factor is any living part of the environment with which an organism might interact, including animals, plants, mushrooms, and bacteria.

An abiotic factor is any nonliving part of the environment, such as sunlight, heat, precipitation, humidity, wind or water currents, and soil type.

Understanding Global Change

One way to understand global systems is to develop a model that shows those systems, the processes that operate within in each system, and ways those systems and processes interact.

Observation is often the first step in asking ecological questions.

Experimentation can be used to test hypotheses. An ecologist may, for example, set up an artificial environment in a laboratory or greenhouse to see how growing plants react to different conditions of temperature, lighting, or carbon dioxide concentration. Other experiments carefully alter conditions in selected parts of natural ecosystems.

Modeling Ecologists make models to help them understand these phenomena. Many ecological models consist of mathematical formulas based on data collected through observation and experimentation. Further observations by ecologists can be used to test predictions based on those models.

3.2 Climate, Weather, and Life

Weather: consists of short-term changes in temperature, precipitation, clouds, and wind from day to day, or minute to minute

Climate: is defined by patterns and averages of temperature, precipitation, clouds, and wind over many years.

Climate change involves changes in temperature, clouds, winds, patterns and amounts of precipitation, and the frequency and severity of extreme weather events.

The global climate system is powered and shaped by the total amount of solar energy retained in the biosphere as heat, and by the unequal distribution of that heat between the equator and the poles.

**Note: At the distance Earth sits from the sun, we cannot feel the heat from the sun. When we experience the sun’s warmth, we are experiencing the transformation of light energy to heat energy.

Greenhouse Effect on Earth

Earth’s average temperature is determined by the balance between the amount of heat that stays in the atmosphere and the amount of heat that is lost to space.

Greenhouse gases consist of carbon dioxide, methane gas, and water vapor. Imbalance of these gases also effect climate change in the biosphere.

Consider how such currents of cold and warm water circulate:

Ocean currents are driven and shaped by patterns of warming and cooling, by winds, and by the locations of continents.

Winds and surface currents affect important external environmental factors, such as temperature and moisture content, of air above them. These interactions shape weather and climate on land areas near oceans.

Regional climate can also effect climate

Regional climates are shaped by latitude, the transport of heat and moisture by winds and ocean currents, and by geographic features such as mountain ranges, large bodies of water, and ocean currents.

NASA images of El Nino 1997 and 2015

More from NASA

3.3 Biomes and Aquatic Ecosystems

Terrestrial Biomes

Identify the 10 biomes by their descriptive conditions.

What kind of life would you expect to living in each?

What type of adaptations might they evolve?

Aquatic Ecosystems (presentation 3.3)

Aquatic organisms are affected primarily by the water’s depth, temperature, flow, and chemistry (amount of dissolved nutrients).
The different conditions of theses aquatic ecosystems will affect what kinds of organisms are able to live in each. Therefore saltwater organisms cannot survive in freshwater and freshwater organisms may not be able to survive in saltwater because of these differences.
Main differences between saltwater (marine) and freshwater ecosystems is the level of salinity.
Freshwater ecosystems can be divided into three main categories: rivers and streams, lakes and ponds, and freshwater wetlands
Saltwater or Marine ecosystems consists of marshes, coastal swamps, coral reefs, and the open ocean

Marine ecosystems :

Typically occupy specific areas within the ocean. Ecologists usually divide the ocean into zones based on depth and distance from shore.
Marine ecosystems are based on distance from shore include the intertidal zone, the coastal ocean, and the open ocean.
Zones based on depth include the photic zone and the aphotic zone. Within these zones live a number of different communities.
Oceans cover three quarters of Earth’s surface and each drop of ocean water down to a depth of 100 meters is home to thousands of phytoplankton. Phytoplankton produce 70 percent of Earth’s oxygen and are the main consumers of carbon dioxide, a greenhouse gas.

The intertidal zone are submerged in seawater at high tide and exposed to air and sunlight at low tide. These organisms, then, are subjected to regular and extreme changes in temperature. They are also often battered by waves and currents. There are many different types of intertidal communities. A typical rocky intertidal community exists in temperate regions where exposed rocks line the shore. There, barnacles and seaweed permanently attach themselves to the rocks.

The coastal ocean extends from the low-tide mark to the outer edge of the continental shelf—the relatively shallow border that surrounds the continents. Water here is brightly lit and is often supplied with nutrients by freshwater runoff from land. As a result, coastal oceans tend to be highly productive. Kelp forests and coral reefs are two exceptionally important coastal communities.

The open ocean begins at the edge of the continental shelf and extends outward. More than 90 percent of the world’s ocean area is open ocean.

The open ocean typically has low nutrient levels and supports only the smallest species of phytoplankton. Still, because of its enormous area, most photosynthesis on Earth occurs in the sunlit top 100 meters of the open ocean.

The permanently dark aphotic zone includes the deepest parts of the ocean. Food webs here are based either on organisms that fall from the photic zone above or on chemosynthetic organisms. Deep ocean organisms are exposed to high pressure, frigid temperatures, and total darkness. Benthic environments in the deep sea were once thought to be nearly devoid of life but are now known to have islands of high productivity. Deep-sea vents, where superheated water boils out of cracks on the ocean floor, support chemosynthetic primary producers.

Freshwater Ecosystems

Only 3 percent of Earth’s surface water is fresh water, provides terrestrial organisms with drinking water, food, and transportation.
Often, a chain of streams, lakes, and rivers begins in the interior of a continent and flows through several biomes to the sea.
Freshwater ecosystems can be divided into three main categories: rivers and streams, lakes and ponds, and freshwater wetlands.

Rivers and streams, lakes and ponds

Near a source, water has plenty of dissolved oxygen but little plant life. Downstream, sediments build up and plants establish themselves. Still farther downstream, water may meander slowly through flat areas. Animals in many rivers and streams depend on terrestrial plants and animals that live along the streams’ banks.

Food webs in lakes and ponds are often based on a combination of plankton—including both phytoplankton and zooplankton—and attached algae and plants. Water typically flows in and out of lakes and ponds and circulates between the surface and the benthos during at least some seasons. This circulation distributes heat, oxygen, and nutrients.

Wetlands

A wetland is an ecosystem in which water either covers the soil or is present at or near the surface for at least part of the year. Wetlands are often nutrient-rich and highly productive, and they serve as breeding grounds for many organisms. Freshwater wetlands have important environmental functions: They purify water by filtering pollutants and help prevent flooding by absorbing large amounts of water and slowly releasing it. Three main types of freshwater wetlands are freshwater bogs, freshwater swamps, and freshwater marshes.

Estuaries

An estuary is a special kind of wetland that is formed where a river meets the sea. Estuaries contain a mixture of fresh water and salt water and are affected by the rise and fall of ocean tides. Many are shallow, which means that enough sunlight reaches the benthos to power photosynthesis. Estuaries support an astonishing amount of biomass—though usually fewer species than freshwater or marine ecosystems—which makes them commercially valuable.

6.2 Ecological Succession

Ecological succession is a series of somewhat predictable events that occur in a community over time. Ecosystems are constantly evolving, and experience major change after disturbances. New species move in, populations change, and other species die out. The diversity among species in an ecosystem increases as succession progresses.

Primary Succession is the beginning on newly-formed rock or areas with no remnants of older communities. This typically happens after volcanic eruptions or as glaciers retreat, causing new, barren rock to be exposed. Ecological succession begins when pioneer species, or the first species to colonize barren areas, move in. They create an environment suitable for other organisms to move in and for the area to sustain growth.

Secondary Succession occurs when a disturbance affects an existing community but doesn’t completely destroy it. This process happens faster than primary succession because parts of the original community still exist. Possible disturbances include: natural disasters like wildfires, hurricanes, and tsunamis, as well as human created disturbances.

6.3 Biodiversity, Ecosystems and Resilience

Reviews on Ecology

Ecosystems Tutorial (cpalms)

Energy Flow Tutorial (cpalms)

Population Tutorial (cpalms)

Page updated

Google Sites

Report abuse