how did the dodo bird extinct

this is the very last post on ecology and the very last post of biology journal.

as mentioned in the previous post, i mentioned that the dodo bird is extinct due to the destruction of the forest (which cut off the Dodo's food supply), and the animals that the sailors brought with them, including cats, rats, and pigs, which destroyed Dodo nests.

so now i would like to further elaborate on them.

After the remote island became inhabited by humans, the dodo's fate was sealed. The poor fowl had lived in relative isolation for so long that it had few defenses and proved to be easy prey for humans and the animals they brought with them. The flightless bird was hunted for sport and food by humans, and its eggs, laid individually in nests on the ground, were devoured by dogs, cats, and pigs. By 1681, the entire species was wipe out. Two similar species were discovered on nearby islands, but sadly, they fared no better and were both extinct by 1750.

On an interesting side note, not only did the extinction of the dodo deprive the world of one of nature's most curious creations, it almost led to the extinction of yet another species, a certain type of tree whose seeds could only germinate after passing through the digestive tract of the dodo. With the disappearance of the dodo, the tree was slowly dying out. There were only 13 trees left when it was discovered that turkeys could also be used to help the seeds activate, and the tree, now known as the dodo tree, has avoided extinction for the time being.

so from here we can link it to the posts on extinction. it was due to the hunters that wiped on all of them. worse still, their generation of babies are also wiped out by the dogs, cats and pigs. this lead to a zero replacement fertility level.

http://ask.yahoo.com/20030715.html

about dodo bird

The Dodo is a lesson in extinction. First sighted around 1600 on Mauritius, an island in the Indian Ocean, the Dodo was extinct less than eighty years later.

there are no complete Dodo specimens. Some of the birds may have been eaten by the Dutch sailors who discovered them. However, the primary causes of their extinction were the destruction of the forest (which cut off the Dodo's food supply), and the animals that the sailors brought with them, including cats, rats, and pigs, which destroyed Dodo nests.

The Dodo's stubby wings and heavy, ungainly body tell us that the bird was flightless. Moreover, its breastbone is too small to support the huge pectoral muscles a bird this size would need to fly. Yet scientists believe that the Dodo evolved from a bird capable of flight into a flightless one. When an ancestor of the Dodo landed on Mauritius, it found a habitat with plenty of food and no predators. It therefore did not need to fly, and, as flying takes a great deal of energy, it was more efficient for the bird to remain on the ground. Eventually, the flightless Dodo evolved.

Scientists at the American Museum of Natural History and other institutions around the world continue to study and document the impact of human activities on the environment. It is hoped that the lesson of the Dodo can help prevent similar extinctions, and aid us in preserving the diversity of life on earth.

http://www.amnh.org/exhibitions/expeditions/treasure_fossil/Treasures/Dodo/dodo.html?dinos

more about extintion and ecology

take a look at this video. i apologize for the inconvience cause becuase i could not upload it.

http://www.youtube.com/watch?v=XbOXUza9ZeE

was thinking about our collective denial of the environmental crisis we’re creating, when I read a blog post by Nicola-Frank Vachon at The Solemn Monkey. (To understand the title, see the very worthwhile video on the “About me” page.) Besides an artistic essay which led me to confront the thought of our own self-destruction, it featured the video below. From the Species Alliance, I think it’s remarkably persuasive in driving home its point about the huge surge in extinctions we’re seeing today.
Our earth has seen five prior waves of mass extinction, the last one being that which eliminated the dinosaurs. This “sixth extinction,” (pdf) as many scientists now refer to it, is the result of human activity, with causes including climate change and deforestation. Key among the underlying drivers of those causes are, of course, the topics we examine here: human population growth, our growing rates of resource consumption, and the drive for unceasing economic growth.
The video made me wonder if the specter of mass extinction, especially when effectively presented, might be enough to break through some of our denial. I would think many people would sense intuitively that a world with half as many species as we now enjoy would be grimly impoverished. Would it be livable? I hope we don’t have to find out first hand. Does the subject of mass extinction have a unique place in our toolbox of ways to wake people up to the realities of our ecological crisis?

an article on ecosystem - "Ecosystem consequences of extinction different than thought"

The loss of seemingly inconsequential animal species from the sea floor has given scientists a new insight into ecosystem impacts that occur when species become extinct.

An international team of scientists – led by the University of Aberdeen - have found that the consequences of biodiversity loss could be very different to what was previously thought.

Researchers say this is because they have discovered that it is the cause of extinction and order in which species are lost - rather than simply the number of species that go extinct - which ultimately determines the ecological impact of extinction.

Rapid changes in biodiversity are occurring globally, yet the ecological impacts of diversity loss remain poorly understood.

Marine coastal ecosystems are among the most productive and diverse communities on Earth and are of significant importance to the regulation of climate, nutrients, and the food chain.

However, the contributions that coastal ecosystems make to these ecological processes are compromised by man’s activities, such as overfishing, habitat destruction and pollution.

Bottom dwelling marine organisms are particularly vulnerable to extinction because they are often unable to avoid disturbance. These organisms are important because they churn up sediments from the bottom of the ocean – a process referred to as bioturbation - which results in nutrients being returned to the water column where they are vital for other species in the food web.

Dr Martin Solan, from the University of Aberdeen’s Oceanlab, led the research which involved collaborators from America and Canada. He said: “Organisms living in the seabed, such as clams, worms and shrimps may not seem that important, but they are essential for regulating and recycling the planet’s resources.”

Scientists have discovered that the effects of extinctions in general can differ from what they had previously predicted. This is because the characteristics of a species that most greatly influence vital ecosystem processes, such as bioturbation, often also determine susceptibility to extinction.

Dr Solan said: “Our findings suggest that previous predictions of what happens to an ecosystem following extinction may be, for better or for worse, far from the reality.”

Current predictions of what happens to an ecosystem following extinction have assumed that species are lost completely at random. This is not necessarily the case - some drivers of extinction target particular attributes of certain species more than others.

Dr Solan added: “We have known for some time that there are general ecological consequences of species extinction. What we didn’t appreciate is that the point at which bioturbation loss begins, depends on both the cause of extinction and, critically, the order in which species are lost”.
The research team based their findings on communities of invertebrate species (like clams, shrimps, worms) from marine samples collected in Inner Galway Bay, Ireland.

The team used the Galway data to mathematically simulate the random extinction of species versus non-random extinctions - where species were lost according to how rare, big or sensitive to pollution they are. These characteristics matter because they are important for determining the degree of bioturbation.

The team also defined how an ecosystem may respond to extinction. The best case scenario assumed that surviving species altered their bioturbation behaviour in order to compensate for the species which had become extinct. The worst case scenario assumed the surviving community failed to respond.

Dr Solan said: “We chose these alternative scenarios of extinction in order to mimic as closely as possible the full range of consequences that known extinction drivers may have on the communities of the marine environment.

“However, our findings are equally applicable to other ecosystems where the cause of extinction targets particular biological characteristics.”
The team’s findings have important implications for the conservation of biological resources and habitat.

Dr Solan added: “If we wish to predict the ecological impacts of extinction, we must first understand why species are at risk and how this risk correlates with the role they play in the ecosystem. It is only when we know these details that we can hope to effectively protect our ecological heritage.”

The team’s findings Extinction and Ecosystem Function in the Marine Benthos appear in the Journal Science.

The research team included the University of Aberdeen; University of California; Ohio Wesleyan University, Delaware; University of Maryland Center for Environmental Science; University of Washington and University of British Columbia.

http://www.abdn.ac.uk/mediareleases/release.php?id=54

introduction to extinction

The idea of individual species becoming extinct is quite familiar; indeed it is a rather sad indictment of our stewardship of the planet that we are all too familiar with extinction. But, in fact, extinction is a rather complex phenomenon. At one end of the continuum we have the notion of a population of organisms evolving into something else. Here, the disappearance of the original phenotype might be accomplished by nothing more than natural turn-over of the generations (anagenesis).

At the opposite end of the spectrum, we have the mass extinctions, where huge proportions of the earth biota disappear more or less simultaneously, within an interval that is, in some sense, short. At least some of the more sensational explanations for these phenomena require the wholesale killing of individual organisms.

Between these two extremes we have a range of possibilities, further complicated by the vagaries of the fossil record and our imperfect interpretation thereof. And always, even in the case of the KT event which cannot be "explained away" in its entirety by meteorite impact, there is the enigma of underlying cause.


Working Definitions

For our purposes, extinction of a single taxon ?whether a species or higher level taxon ?is accomplished when the last representative of that taxon dies. Of course we could also distinguish the point at which the organism was no longer able to reproduce (e.g. when the population density of a dioecious species drops below its reproductive threshold) but any such subtlety is pointless: The fossil record is not a good witness to the fate of individuals, so our notions of extinction are necessarily approximate. In practice, to the paleontologist, extinction is the last (most recent) occurrence of an identifiable fossil.

We have more difficulty with the concept of mass extinctions. Ward 2000 (pp. 6-7) offers the definition that mass extinction events are geologically short intervals of intense species extinction. However, this definition admits events such as the decimation of the South American marsupial fauna following the establishment of a land bridge with North America in the late Pliocene, which is almost certainly not his intention. Of course such events are also interesting extinction phenomena. But to properly capture the idea of Mass Extinction, it also seems necessary that a mass extinction should be global in extent and involve participants?from widely diverse taxonomic groups.

http://www.peripatus.gen.nz/paleontology/extinction.html

Energy and nutrient transfers

All living organisms require energy. The ultimate source of all this energy is the sun. Solar energy is trapped by plants, and then transferred from organism to organism in a food chain. At each stage in this transfer much of the energy is lost to the environment.

Living organisms also require nutrient elements - in particular carbon and nitrogen - which they take from the environment. If this were just a one-way process, ecosystems would soon run out of these nutrients; but in fact they are returned to the environment, with the help of bacteria, via nutrient cycles

In every ecosystem, energy is transferred along food chains from one trophic level to the next. But not all the energy available to organisms at one trophic level can be absorbed by organisms at the next one: in fact the amount of available energy decreases dramatically at each level. Why?
Some of the available energy goes into growth in biomass and the production of offspring: this energy does become available to the next trophic level. However most of the available energy is used up in other ways:
Some is used up at the first trophic level as a result of photosynthesis, which uses up lots of solar energy in making glucose.
Some is used up in respiration, and given off as heat
Some is lost, in the form of biological material and heat, through excretion. (This energy is actually transferred to the decomposer food chain: more about this later!)
Some is used for movement and transport.
All the energy used in these ways returns to the environment, and is not available to the next trophic level. so much energy is lost at each level that however much you start off with it is almost all gone by the fourth trophic level

http://www.bbc.co.uk/schools/gcsebitesize/biology/livingthingsenvironment/2energyandnutrienttransferrev2.shtml

secondary consumers (canivores)

Secondary Consumers consume the primary consumers. Energy that had been used by the primary consumers for growth and storage is thus absorbed into the secondary consumers through the process of digestion. As with primary consumers, secondary consumers convert this energy into a more suitable form (ATP) during respiration. Again some energy is lost from the system, since energy which the primary consumers had used for respiration cannot be utilised by the secondary consumers.

secondary consumers can also be named as canivores

Characteristics commonly 'associated' with carnivores include organs for capturing and disarticulating prey (teeth and claws serve these functions in many vertebrates) and status as a predator. In truth, these assumptions may be misleading, as some carnivores do not hunt and are scavengers (though most hunting carnivores will scavenge when the opportunity exists). Thus they do not have the characteristics associated with hunting carnivores. Carnivores have comparatively short digestive systems as they are not required to break down tough cellulose found in plants.

http://en.wikipedia.org/wiki/Carnivore
http://en.wikipedia.org/wiki/energyflow