Advanced Environmental Biotechnology II - 2013

Natural environments - living and non-living Food

Webs and Complex Interactions

Types of Organisms

All populations living together and the physical factors with which they interact make up an ecosystem.

population 개체군 group of organisms all of the same species, which interbreed and live in the same place at the same time. 같은 시기 , 같은 장소에서 살며 교배하는 동종의 생물체 모임 .

Living things – plants, animals and micro-organisms. The classification of living organisms is constantly being revised.

The above diagram shows a suggested relationship between the different groups of organisms. This has been decided by comparing the DNA of the organisms.This has been developed by Carl R. Woese.

Earth formed 4.6 x 109 years ago. Many different physical, chemical, biochemical, and (later) biological events happened on Earth. For ~70% of life’s history, prokaryotes were the sole or dominant life forms.

Prokaryotes (Bacteria and Archaea) were (and are today) major causes of geologic, atmospheric, geochemical, and climatic changes that have occurred in the Earth’s history.

More recently, modern eukaryotes (especially land plants) have added more major biogeochemical and ecological change during the most recent 1.4 x109 years. But prokaryotes are still the most important life on Earth.

Prokaryotes are ~60% of the total biomass. Prokaryotes carry out as much as 60% of total respiration of some terrestrial habitats.

Prokaryotes can be found in some of Earth’s habitats where there is no eukaryotic life due to extremes (too much or too little) of height, depth, pressure, pH, salinity, heat, or light.

Prokaryotes can be used to alter ecosystems in many ways.Examples: Humans use prokaryotes to breakdown sewage, to clean up pollution, and to increase nutrients in soil.

Producers, Consumers, or Decomposers

Energy passes from organism to organism in food webs.

Photosynthesis

(photo=light, synthesis=putting together)The synthesis of glucose from sunlight, carbon dioxide and water, with oxygen as a waste product. It is an extremely complex process, comprised of many coordinated biochemical reactions. It occurs in higher plants, phytoplankton, algae, some bacteria, and some protists, organisms collectively referred to as photoautotrophs.

http://en.wikipedia.org/wiki/How_plants_make_food

Non-photosynthetic Autotrophs

Some bacteria live around deep-sea vents or deep underground. They take energy from chemicals coming from the Earth's interior and use it to make sugars. Organisms living in extreme conditions are called extremeophiles. Chemoautotrophs

Chemotrophs are organisms that obtain energy by the oxidation of electron donating molecules in their environments. Chemoautotrophs (or chemotrophic autotroph), synthesize all necessary organic compounds from carbon dioxide. Several groups: methanogens, halophiles, sulfur reducers, nitrifiers, anammoxbacteria and thermoacidophiles.

Respiration releases the energy stored in sugars and

fats.

Chemoheterotrophs (or chemotrophic heterotrophs) must ingest organic building blocks that they are incapable of creating on their own. Most chemoheterotrophs derive energy from organic molecules like glucose.

Energy Flow

When light strikes a leaf, most of it is reflected; about 1% is converted to energy-rich tissues.  A herbivore or plant-eating animal, that eats the leaf stores only about 10% of that energy.  The carnivore that eats the herbivore only stores a small percentage of that energy.

Energy Flow Through the Ecosystem

The Net Primary Productivity (NPP) of an ecosystem is how fast it adds energy or biomass, minus the energy it uses for respiration.  

Biomass

Different ecosystems have different NPP values.

A large amount of all the NPP on earth is used by humans (in agriculture, harvested forests, for energy needs, etc.).

The most productive ecosystems (highest NPP) are

wetlands

and

estuaries.

Carbon Cycle

http://www.epa.gov/sequestration/local_scale.html

http://www.epa.gov/sequestration/ccyle.html

The vegetation absorbs carbon dioxide (CO2) from the atmosphere by the net primary production (NPP, gross primary production minus respiration). NPP is estimated from temperature, precipitation, and atmospheric CO2 concentration by the observational empirical formulation; NPP generally increases along with the increase in those three factors.　 The carbon absorbed from the atmosphere to the vegetation is distributed to the parts of vegetation (leaf, branch, stem, and root), then transferred into litter, humus, and charcoal according to the turnover times estimated by the observations, and finally emitted to the atmosphere by the soil respiration.

(C) 2008 Meteorological Research Institute. All Rights Reserved. http://www.mri-jma.go.jp/Project/1-21/1-21-1/carbon_land-en.htm

Other nutrients are cycled

Inorganic nutrients do not contain carbon-carbon bonds. These inorganic nutrients include phosphorous,

nitrogen,

oxygen

Autotrophs obtain these inorganic nutrients from the inorganic nutrient pool

This is usually the soil or water surrounding the plants or algae.

These nutrients are passed from organism to organism as one organism is consumed by another.

All organisms die and become detritus, food for the decomposers.

The inorganic nutrients are returned to the soil or water to be taken up again.

Nitrogen has a complex cycle

Nitrogen Cycle

http://www.alken-murray.com/Nitrogen.html - not for web page

Many of the steps in the nitrogen cycles are controlled by microogranisms

http://www.epa.gov/maia/html/nitrogen.html

Because of human actions much more nitrogen is being cycled through the nitrogen

cyclesRain can wash the excess of fixed nitrogen into lakes and rivers and fertilizes the growth of green algae. When the algae blooms die off, the dissolved oxygen is absorbed. Aquatic and marine life which depend on oxygen die off as a result. This process is called eutrophication.

http://library.thinkquest.org/04oct/01590/pollution/eutrophication.html

http://www.compulink.co.uk/~argus/Dreambio/fertilisers%20and%20crops/probelms%20with%20fertilisers.htm

Biodiversity

Gewin V (2006) Beyond Neutrality—Ecology Finds Its Niche. PLoS Biol 4(8): e278 doi:10.1371/journal.pbio.0040278

The ecosystem diversity is the number of different species in an ecosystem

The greatest ecosystem diversity is found in a rainforest.  The least is found in a desert.

The greater the diversity of an ecosystem, the greater its environmental resistance or stability under stress.

Stress is such things as climate change, immigration of alien species, or even extinction of one or several species in the ecosystem.

The current facts show that communities may be ruled by weak trophic interactions. Adding or taking away any species (weak or strong) can lead to big changes in community composition and structure. Decreasing biodiversity increases the probability that ecosystems collapse. Strong community changes can follow the removal or addition of just a single species.

Kevin Shear McCann (2000)NATURE | VOL 405 p228-233 11 MAY 2000 www.nature.com

In other words …

If you change a small part of an ecosystem you might get large changes over all of the ecosystem.

Interactions between Organisms

When studying ecosystems the following terms are used.Competition: organisms can compete for space , food etc.Predation: one organism captures and feeds upon another called the prey.Herbivory: This is a type of predation where primary consumers eat plants.Symbiosis: an interaction between two organisms. Parasitism: the interaction is harmful to one of the organisms, Mutualism: the association is helpful to one or both.Commensalism: one organism benefits while the other is not affected.

The Clownfish lives between the stinging arms of the sea anenome

What does the clownfish gain?What does the sea anenome gain?Pair and Share

Common Clownfish (Amphiprion ocellaris) in their Magnificent sea anemone (Heteractis magnifica) home.

Clownfish and sea anenomes have mutual symbiosis

The fish protects the anemone from anemone-eating fish.

The stinging tentacles of the anemone protect the anemone fish from its predators.

Endosymbiosis

This is the case of symbiosis where one organism lives inside the others cells.The endosymbiont gains protection and possibly some essential nutrients from the host cytoplasm. The host has a food source when its usual food source is depleted.

Wernegreen JJ (2004) Endosymbiosis: Lessons in Conflict Resolution. PLoS Biol 2(3): e68 doi:10.1371/journal.pbio.0020068

Aphid host of Buchnera endosymbionts

(2003) Developmental Origins and Evolution of Buchnera Host Cells. PLoS Biol 1(1): e24 doi:10.1371/journal.pbio.0000024

More Symbiosis

Another example of symbiosis can be found in the close relationships of some plants with nitrogen fixing bacteria.The plants provide sugars which the bacteria use for energy.The bacteria fix nitrogen in a way which accessible for the plant.