Lecture 1 Ecosystems: Background and additional research

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Book Notes Chapter 1
peps just so you know these are by NO MEANS extensive, you should really read the book, cuz to be honest… some of this may only make sense to me :) :)

Ecology- the science by which we study how organisms interact in and with the natural world.

Ecological system
• The unification of organisms, assemblages of organisms and organisms together with their environment by the regular interaction and interdependence of their parts
• Can be as small as individual organisms or as large as the biosphere
• Each smaller ecological system is a subset of the next larger one, so the systems form a hierarchy
• Organism - most fundamental unit of ecology, the elemental ecological system. No smaller unit (i.e. organ, cell, etc.) has a separate life in the environment
• Ecosystem - assemblages of organisms together with their physical and chemical environments—large and complex. It has internal processes and exchanges with external surroundings.
• Biosphere - all the environments and organisms on earth, the ultimate ecological system. Only things outside of the biosphere is the energy from sun and heat lost to space. Everything else is internal.
• Population - many organisms of the same kind living together
• Community - many populations of different kinds in the same place

Different approaches to Ecology

  • organism approach- emphasizes the way in which individuals form, physiology and behavior help it to survive in its environment. (for more see page 5).
  • population approach- concerned with the different quantity of individuals, the gender (read sex, since gender is technically something expressed and socialized, rather than synonymous with sex) ratio, age class size, genetic composition of a population over time.
  • community approach- seeks to understand the variety an relative quantity of different types of organisms existing in the same location.
  • ecosystem approach- describes organisms and their tendencies by way of their common 'tendencies'. example: nitrogen, oxygen, carbon ect. How these are effected by climate and other physical factors.
  • biosphere approach- examines movements of air and water, and the energy of chemical elements they contain.

Plants-use sun's energy to synthesize organic matter (there are other organisms that can do that, too), collecting carbon dioxide from the atmosphere to store as sugars and transpiring water

Animals-consume other organisms or what remains of them, and can exchange substances internally

Fungi- primary agents of rot (most consist of hyphae).

Protists- single-celled eukaryotic organisms; some can photosynthesize and form clusters together, others feed on organic matter or are predators or parasites.

Bacteria- prokaryotic single-celled organisms that use many biochemical mechanisms to transform energy

Symbiosis- a close physical relationship between two types of organisms (humans & the bacteria that lives on our skin).

Mutualism- each provides something in the relationship that is beneficial to the other (whales and the little dudes that eat the stuff off their skin).

Parasites- organisms which live in another organism and feed off it, but don't kill it (pretty much a live-in predator as the book puts it)

Parasitoids - organisms which live in or on another organism, feeding off of it while it's alive and killing it very slowly (as opposed to a predator, which generally kills its prey relatively quickly and consumes the dead prey, or a parasite, which does not directly kill its host)

Pathogens- parasites that cause disease symptoms.

Habitat- place where an organism lives; defined by certain features, including predominant vegetation (forests, deserts) or animal-made structures (coral reefs)

Niche- the conditions an organism can tolerate and ways behaves or interacts in life—its role in the ecosystem. Can vary between different creatures in different places.

Variations in an ecological system can occur in scales (different sizes of dimensions) in time and space, and different elements of an ecological system may have scales of patterns which match the processes.

Ecological systems work within their physical and chemical limits, exist in dynamic steady states where gains and losses in each part of the system are balanced, expend energy to maintain themselves, and change (evolve) over time, and organisms can develop adaptations (attributes of structure and functions) to suit the conditions they live in.
Natural selection: well-adapted individuals, able to respond to any changes, survive in certain ecosystems.

Some where in the chapter it goes over the scientific method, and frankly… if you don't know it by now you are screwed.. but just in case this is new to you, click here

Most experiments involve manipulations to controlled environments.

Natural experiment- observations of variations in natural surroundings which create controlled experimental variables (like observing how the same species of animal has adapted to different terrains in similar climate conditions)

Human influences can impact the natural world, and those influences have increased more and more as more humans appeared.

Compartment models
Ecosystems can be shown in models, with each element in different compartments, with arrows showing how cycles are exchanged between the elements—several models can even be linked.

Types of ecosystem variation

  • temporal variation- Changes in conditions over time.
  • spatial variation- Changes in conditions over area.

Microcosm- an experiment that seeks to copy a natural environmental system in a lab on a much smaller scale.

Notes from Terrestrial Ecosystems in changing environments

Lindeman's principal contributions to Ecology:

1. Stress major role of tropic function to emphasize the quantification of trophic functions to determine succession.
2. Establish validity of theoretical facet of ecology
3. Identified basic dynamic processes (ex. energy flow) which integrated into long term change.

Trophic-Dynamics (2 major conflicting theories on it)- tries to explain how ecosystems change
1. Individuals change first to adapt to others (Rich)
2. The environmental system we are a part of makes us the way we are (Spencer).

Ecosystem ecology- transfer of energy

Ecological succession- following a changing event there is a predictable/common trend for a new community to develop.

debate here: do complex systems exist or do natural systems always change over time.

Data on succession theory is limited and may be biased, thus it is hard to solidify.

Another way to put it: Biogeocoensis is an ecosystem with a fixed size. This fixed size is usually denoted as an area with a somewhat uniform species composition, geological composition and atmospheric condition(s). Shugart suggests that this concept is similar to the "super-organism" concept put forth by FE Clements and J Phillips.
Biogeocoensis DOES NOT EQUAL ecosystem (ex. watershed is an ecosystem, but not all ecosystems are watersheds.)

Some more information about Biosphere (photo shown in PPT)
[source: http://www.b2science.org/b2/about-history.html]

The property as it now stands was built starting in 1986. In 1991 and 1994, two experiments were run to test space colonization theories, where groups of “Biosphereians” were sealed in the structure to see if they could survive. From 1996-2003, Columbia University ran the facility, conducting research and offering academic programs for college students. Since 2007, the University of Arizona has been running the facility, continuing scientific research and also offering public tours and a conference center.

A few quick facts:
• Includes five biomes
• 3.14 acre facility
• 7,200,000 cubic feet of sealed glass, 6,500 windows
• 91 feet at highest point

More interesting reading: http://en.wikipedia.org/wiki/Biosphere_2

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