The monarch butterfly goes through four stages of development. Life for a monarch butterfly begins as an egg hatched from an adult. This egg then develops into a worm-like larva caterpillar. In the pupa or chrysalis stage, the caterpillar spins a silk pad on a twig or leaves and hangs from this pad by its last pair of prolegs. It hangs upside down in the shape of a "J" and then molts leaving it encased in a green exoskeleton. The mature butterfly emerges after about two weeks and feeds on a variety of flowers including milkweed flowers, red clover and goldenrod.
In typical amphibian development, eggs are laid in water and larvae are adapted to an aquatic lifestyle. Frogs, toads, and newts all hatch from the egg as larvae with external gills. Afterwards, newt larvae start a predatory lifestyle, while tadpoles mostly scrape food off surfaces with their horny tooth ridges.
Many marine species have evolved a system where they release their eggs and sperm into the water at the same time, and fertilisation takes place in the sea over one or two days. This increases their chance of reproductive success.
Then, larvae join the other plankton, eating and growing before metamorphosing into adults. Most marine invertebrates and many fish have a life cycle with pelagic larvae or even pelagic eggs. These have the capacity to be transported long distances, and so spread the species around to other places.
The need for metamorphosis is clear when the relative size of eggs and adults is understood. A mature Atlantic cod can reach two metres long, and weigh over 200 pounds (96 kg). The female will produce over 100,000 eggs in a single spawning, and the resulting larvae are quite tiny. There is no way they could live like the adults, which are more or less top predators. The larvae cannot even swim against the current. Therefore, they must live a different kind of life before they can live as the adults do.
Their development is packaged into stages, and each stage has adaptations to life at its stage. The sharp distinction between stages (best seen in insects) is presumably because a longer transition would leave the juvenile less fit, either at its younger or older ways of life.
Resilience
Resilience generally means the ability to recover from some shock or disturbance.
There are different meanings for
Resilience is a term used in psychology to describe the capacity of people to cope with stress and catastrophe. It is also used to indicate a characteristic of resistance to future negative events. This psychological meaning of resilience is often contrasted with "risk factors".
In physics and engineering, resilience is defined as the capacity of a material to absorb energy when it is deformed elastically and then, upon unloading to have this energy recovered. In other words, it is the maximum energy per volume that can be elastically stored. It is represented by the area under the curve in the elastic region in the Stress-Strain diagram.
Modulus of Resilience, formula_1, can be calculated using the following formula: formula_2, where formula_3 is yield stress, E is Young's modulus, and formula_4 is strain.
An example of a biomaterial which has a high resilience is articular cartilage, the substance lining the ends of bones in articulating joints such as the knee and hip.
In ecology, resilience has been defined in two competing fashions that emphasize two different aspects of stability.
One definition is the rate at which a system returns to a single steady or cyclic state following a perturbation. This definition of resilience assumes that behavior of a system remains within the stable domain that contains this steady state.
When a system can reorganize, that is shift from one stability domain to another, a more relevant measure of ecosystem dynamics is ecological resilience. It is a measure of the amount of change or disruption that is required to transform a system from being maintained by one set of mutually reinforcing processes and structures to a different set of processes and structures.
The second definition emphasizes conditions far from any steady-states, where instabilities can flip a system into another regime of behavior - i.e. to another stability domain. In this case resilience is measured by the magnitude of disturbance that can be absorbed before the system changes its structure by changing the variables and processes that control behavior. This type of resilience has been defined as ecological resilience.
Economic resilence is the ability of a local economy to retain function, employment and prosperity in the face of the perturbation caused by the shock of the loss of a particular type of local industry or employer.
Within the broad domain of industrial safety, the term resilience has come into use to emphasise that safety must be proactive as well as reactive. Whereas conventional risk management approaches emphasise calculation of failure probabilities, resilience engineering looks for ways to strengthen the ability of organisations to create processes that are robust yet flexible.
Resilience is the ability of the network to provide and maintain an acceptable level of service in the face of various faults and challenges to normal operation.
Resilient networks aim to provide acceptable service to applications:
St Andrews
St Andrews is a town, that has its name from Saint Andrew the Apostle and is a former royal burgh on the east coast of Fife, Scotland, and an important home of golf. It has a population of about 18 000, and stands on the North Sea coast between Edinburgh and Dundee. It is home to Scotland's oldest university, the "University of St Andrews".
The town is called "home of golf" for two reasons. First, the "Royal and Ancient Golf Club", founded in 1754,has authority over the game worldwide except in the USA and Mexico. Second, the beautiful "links" (acquired by the town in 1894) is the most frequent venue for The Open Championship, the oldest of the Men's major golf championships.
Visitors travel to St Andrews in great numbers for several courses ranked amongst the finest in the world, as well as for the sandy beaches.
The Cathedral of St Andrew was at one time Scotland's largest building. It was founded by Bishop Robert (1122 - 1159). It was not completed and consecrated until 1318 in the reign of Robert the Bruce (1306-29).
St Rule's tower stands in the Cathedral grounds but is older than the cathedral. Probably it was part of the Cathedral up to the early 12th century.
The ruins of "St Andrews Castle" stand on a rock at the sea. It is said that Bishop Roger erected the first stone castle on the site about the beginning of the 13th century as an episcopal residence.
The University of St Andrews owed its origin to a society formed in 1410 by Lawrence of Lindores, abbot of Scone and a few others.
The University library, which now includes the older college libraries, was founded about the middle of the 17th century, rebuilt in 1764, and improved in 1829 and 1889 - 1890.
The modern buildings, in the Jacobean style, were erected between 1827 and 1847. University College, Dundee, became in 1890 affiliated to the University of St Andrews.
St Andrews (disambiguation)
The element St Andrew, St. Andrews or St. Andrew's is found in the names of many places and institutions. All of them are named after Saint Andrew, a Christian saint and one of the New Testament Apostles.
Saint Andrew
Other saints who share this name include:
British Isles and Europe
North America
Australia, New Zealand, Japan
Egypt
Israel
Malta
Morocco
Other uses
See also
1911 Encyclopædia Britannica