R and K selection

As the name implies, r-selected species are those that place an emphasis on a high growth rate, and, typically exploit less-crowded ecological niches, and produce many offspring, each of which has a relatively low probability of surviving to adulthood.

HIGH (Reproductive Rate) = R
LOW (Reproductive Rate) = K

K species live in populations that are near or at the equilibrium conditions for long periods of time. Competitive for limited resources is very important in these environments.
I.e. Lemmas, Giraffe, elephants and bats.

R species live in populations that are highly variable. the fittest individuals in these environment have many offspring and reproduce early.  
I.e. Mosquitos and Toads.


Figure 1. A table showing r-K scale of reproductive of balancing egg outputs

Dis/Advantages of being a K species;

• reproductive rate last long time along with parental care making them a weakness to a competitive environment. (Dis)
• More care to young makes them more ability to survive in the wild as they will have learned behaviours from parents (Ad)
• The young will have be dependant on the mother which in order makes the mother a target for predators as she has herself to protect as well as her young (Dis)
• Fewer, Larger offspring. (Dis)
• Later reproductive age (Dis/Ad)
• High parental Care and protection for offspring (Dis)
• Larger Adults (Ad)
• Adapted to stable conditions of the environment (Ad)
• Population size fairly stable and usually close to carrying the capacity (Ad)

Dis/ Advantages of being a R species;

• where there is a short reproductive period there is less weakness for the a competitive environment (Ad)
• Likely that more young is produced known that at least one young will survive however they do have to learn on there own due to lack of parental care. (Dis)
• No young dependent on mother however this means lack of survival (Dis)
• Lower population growth rate (Dis)

Figure 2; Comparison chart for the R and K

 

Gaia Theory

What Is the Gaia Theory?

The Gaia hypothesis, also known as the Gaia theory/ Gaia Principle, proposes that organisms interact with their inorganic surroundings on Earth to form a synergistic self-regulating, complex system that helps maintain and perpetuate the conditions for life on the planet.

Figure 1. A simple Hypothesis.

Lovelock's Initial Hypothesis...

James Lovelock had defined Gaia as the follows;

"a complex entity involving the Earth's Biosphere atmosphere, Oceans and soils; the totality constituting a feedback or cybernetic system which seeks an optimal physical and chemical environment for life on this planet."

Lovelock suggested that life on Earth provides a cybernetic, homeostatic feedback system operated automatically and unconsciously by the biota, leading to broad stabilization of the global temperature and chemical composition.

lovelock claimed the existence of a global control system of the surface temperature, atmosphere composition and ocean salinity. He defended his claims with these points below;

• "The global surface temperature of the earth has remained constant, despite an increase in the energy provided by the sun"

• "Atmospheric composition remains constant, even though it should be unstable"

• Ocean Salinity is constant

 Gaia in Ecology?

Ecologists generally consider the biosphere as an ecosystem and the Gaia hypothesis, through a simplification of the of that original proposed, to be consistent with a modern vision of a global ecology, relaying the concepts of the biosphere and biodiversity.

Figure 2. More Info on Gaia Theory.
 

 

The Coppice Cycle Modern/ Ancient

In a coppiced woodland, young tree stems are repeatedly cut down to near ground levels. In subsequent growth years, many new shoots will emerge and after a number of years of the coppiced tree or stool is ready to be harvested and the cycle will be ready to start again.

coppicing was used in medieval times however not like it is today, it was operated to produce a crop of wood of different ages. Five year old coppice would be used for sheep hurdles, hedging stakes and thatching spars. All older wood could be used for fencing material, furniture and firewood as it lasted longer then developing wood. The cutting of different areas at different times produced age structuring.

Whereas, through the 18th and 19th centuries coppiced woodlands provided industrial charcoal for smelting of iron and bark was used for the tanning of liquors.

Fig 1.Hothfield Common;
 Hardly any
trees in 1961 

Fig 2. Trees encroaching and
covered most of the bogs in 1972.

However, by the mid- twentieth century coppicing was in a rapid decline and therefore many coppicing woodland was replaced with conifers or just neglected. Today society have protection over land with Coppicing trees such as Oak and Breach for example Hothfield Common as the land was neglected over time to a point where there was no woodland and the bogs began to dry up.





Management at Hothfield Commons do use the coppice cycle however only to a point where they can maintain the woodland so it does not engulf the bogs, the wood is used for the local people for firewood much like the medieval times.

Refeances /Further Reading

Hothfieldmemories.org.uk. (2016). Conservation of the bogs and heathlands | Hothfield Common - a unique heathland environment | Places | Hothfield Memories. [online] Available at: http://www.hothfieldmemories.org.uk/page/hothfield_common_-_a_unique_heathland_environment [Accessed 6 May 2016].

The Law of Thermodynamics

The Laws Of Thermodynamics

There are 3 laws of thermodynamics however there is a zeroth law as well (Don't forget that!)

0th law;

If two systems are in thermal equilibrium independently system, they must be a thermal equilibrium with each other. they must be in thermal equilibrium with each other.

1st Law;

When energy passes, as work as heat, or with matter into or out from a system, its internal energy changes in accord with the law of conservation of energy.

• In terms of The System models this law would be used as an approach to pressure drop in open system or how much energy is required by an organism.
• In a nutshell first law simply means conservation of energy, or it states that energy is getting transformed from one form to another form.

Open System

Figure 1; representation of an open system (contaminator) with the equation by each side to work out the input and output

Closed System

Figure 2; shows how the cylinder is a closed system and is in the as the Q is it input and W is the Weight

it will increase by a quantity Q, because it is absorbing energy. And it will decrease by a quantity W

therefore the following equation is needed;

Figure 3; Equation meaning Heat and Energy = Quality - work

But remember to change the equation!

(This could then become an open system as in figure 1.)

2nd Law;

In a natural thermodynamic process. the sum of entropies of the interacting thermodynamic systems increases.

• Take your no equilibrium system, and carve it up (Mathematically, not physically) into smaller subdomains, each of which has a fairly constant temperature throughout. They don't have to all have the same temperature, they only need to have their own temperature. You treat each subdomain like an "isolated" system, computing all the internal changes in entropy and energy, and then add in any energy and/or entropy that comes across the boundary from any other subdomain that the subdomain in question is in contact with

3rd Law;

The entropy of a system approaches a constant value as the temperature approaches absolute zero. With the exception of non-crystalline solids the entropy of a system at absolute zero is typically close to zero and is equal to the logarithm of the multiplicity of the quantum ground states

References/Further Reading;

Learnengineering.org. (2016). First Law of Thermodynamics for an Open System ~ Learn Engineering. [online] Available at: http://www.learnengineering.org/2013/03/frist-law-of-thermodynamics-open-system.html [Accessed 24 Apr. 2016].

Tim-thompson.com. (2016). Entropy and the 2nd Law in Open Systems. [online] Available at: http://www.tim-thompson.com/entropy3.html [Accessed 26 Apr. 2016].