Hello Nobleresearcher,
Below you will find information and links to articles regarding your
questions about dinosaurs. Due to copyright restrictions I cannot
reproduce the full text of each article. Just follow the link below
each excerpt to read each one in its entirety.
How many types of dinosaurs are known?
?Approximately 700 species have been named. However, a recent
scientific review suggests that only about half of these are based on
fairly complete specimens that can be shown to be unique and separate
species. These species are placed in about 300 valid dinosaur genera
(Stegosaurus, Diplodocus, etc.), although about 540 have been named.
Recent estimates suggest that about 700 to 900 more dinosaur genera
may remain to be discovered.
Most dinosaur genera presently contain only one species (for example,
Deinonychus) but some have more (for example, Iguanodon). Even if all
of the roughly 700 published species are valid, their number is still
less than one-tenth the number of currently known living bird species,
less than one-fifth the number of currently known mammal species, and
less than one-third the number of currently known spider species.?
USGS Information Services: Dinosaurs
http://pubs.usgs.gov/gip/dinosaurs/
BBC
http://www.bbc.co.uk/dinosaurs/dig_deeper/faq_general.shtml#four
How many dinosaurs were there?
?There are over dinosaur 500 genera (the plural of genus) that have
been found, named and scientifically accepted.
There are about an additional 100 genera that are dubious (these are
frequently referred to as nomen dubium). These dinosaurs, usually
represented by very incomplete fossils, may actually be examples of
other, already named genera.?
Enchanted Learning: Dinosaur FAQ
http://www.enchantedlearning.com/subjects/dinosaurs/questions/faq/Habitat.shtml
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Most dinosaurs ate plants
?Some dinosaurs ate lizards, turtles, eggs, or early mammals. Some
hunted other dinosaurs or scavenged dead animals. Most, however, ate
plants (but not grass, which hadn't evolved yet). Rocks that contains
dinosaur bones also contain fossil pollen and spores that indicate
hundreds to thousands of types of plants existed during the Mesozoic
Era. Many of these plants had edible leaves, including evergreen
conifers (pine trees, redwoods, and their relatives), ferns, mosses,
horsetail rushes, cycads, ginkos, and in the latter part of the
dinosaur age flowering (fruiting) plants. Although the exact time of
origin for flowering plants is still uncertain, the last of the
dinosaurs certainly had fruit available to eat.?
USGS Information Services: Dinosaurs
http://pubs.usgs.gov/gip/dinosaurs/
?Some dinosaurs were carnivores (meat-eaters) but most were herbivores
(plant-eaters). In any food chain, there have to be more organisms at
the lower levels of the chain because the transfer of food energy is
inefficient and much of the energy is wasted. During the Mesozoic Era
(as is other times), plant diversity was greater than animal
diversity.
If you look at dinosaur genera, roughly 65 percent of the dinosaurs
were plant eaters and 35 percent were meat-eaters (or omnivores).?
Enchanted Learning: Dinosaur FAQ
http://www.enchantedlearning.com/subjects/dinosaurs/questions/faq/Habitat.shtml
?Do you know what dinosaurs ate??
?Their tooth structure is a dead-givaway. Sharp toothed, serated teeth
are meat-eaters, whereas the plant eaters have a variety of teeth for
sawing, crushing and chewing plant material.?
http://www.isgs.uiuc.edu/faq/dino-faqs/pdq80.html
?Most dinosaurs ate plants, but some were meat-eaters. The meat-eaters
were often equipped with sharp claws and teeth, and probably used
either speed or stealth to capture their prey.?
Wildlife Education, Ltd.
http://www.zoobooks.com/newFrontPage/animals/animalFacts/sniglet_d.htm
Dinosaur Data Files
Choose a dinosaur and then look at the fact line "food" to see exactly
what things that kind of dinosaur ate.
http://www.nhm.ac.uk/education/online/dinosaur_data_files.html
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Habitat
?Paleontologists now have evidence that dinosaurs lived on all of the
continents. At the beginning of the age of dinosaurs (during the
Triassic Period, about 230 million years ago) the continents we now
know were arranged together as a single supercontinent called Pangea.
During the 165 million years of dinosaur existence this supercontinent
slowly broke apart. Its pieces then spread across the globe into a
nearly modern arrangement by a process called plate tectonics.?
USGS Information Services: Dinosaurs
http://pubs.usgs.gov/gip/dinosaurs/
?Dinosaur remains have been found on every modern continent, though,
and seem to have lived in deserts, forests, swamps and plains. They
were obviously very adaptable. Dinosaurs even seem to have lived near
the poles as the climate was much warmer at the time and it would not
have been cold enough to have ice there. However, because it is dark
in these areas for much of the year, plants would not have grown and
there would have been big food shortage problems. Perhaps the
dinosaurs migrated away from the poles during the winter to areas
where there was more warmth and light like many modern arctic
animals.?
BBC: Walking with Donosaurs
http://dsc.discovery.com/stories/dinos/bbc/howdoweknow/q29.html
What kind of habitat did the dinosaur live in?
?Habitats are very difficult to infer from the sparse fossil data that
is generally available. A few of the dinosaur's contemporaneous plant
or animal fossils are sometimes found, but even then, determining what
the environment was like is pretty difficult. Paleontologists usually
refrain from saying much about particular dinosaurs' habits because of
this.?
Enchanted Learning: Dinosaur FAQ
http://www.enchantedlearning.com/subjects/dinosaurs/questions/faq/Habitat.shtml
At the following links you will find more detailed information
regarding the Dinosaurs Habitat.
http://www.dinotreker.com/dh.html
http://www.dinotreker.com/dh1.html
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Extinction
Paleontologists have found out that dinosaurs went extinct some 64-66
million years ago.
?The question of why the dinosaurs went extinct is one of the most
frequently asked questions to all dinosaur palaeontologists. (. . .)
Probably the two most likely are: the regression and habitat loss
hypothesis (gradualistic) or, the extraterrestrial impact hypothesis
(catastrophic).?
Gradualist Theory
?It suggests that the extinction of these groups was due to climate
change.The climate at the end of the Cretaceous was cooling - and a
fall in sea level reducing dinosaurian and shallow water marine animal
habitats.?
Impact Theory
?The impact hypothesis gets a lot of press coverage because it is
spectacular. There is good geophysical evidence for the occurrence of
an asteroid impact at the end of the Cretaceous. (. . .) It has been
suggested that the impact would have triggered a nuclear winter
scenario that would have caused the death of the dinosaurs as well as
the pterosaurs, several families of birds and mammals and also marine
animals such as the plesiosaurs and ammonites.?
BBC
http://www.bbc.co.uk/dinosaurs/chronology/65/
There are numerous theories for this great extinction, but at present
only three are taken seriously:
?Fossil evidence shows that there was a gradual decline in the
abundance and variety of dinosaurs during the last 10 million years of
the Cretaceous period. This may have been because the climate became
much cooler and drier.?
?In India, huge volcanic eruptions unleashed enormous quantities of
lava, volcanic ash and poisonous gas which would have caused
widespread climatic change.?
?At about the same time a large asteroid struck the Earth forming a
240 kilometre crater in what is now the Yucatan Peninsula in Mexico.
This impact would have caused - among other disasters - several
extremely cold months or years because of dust in the atmosphere.?
BBC
http://www.bbc.co.uk/dinosaurs/dig_deeper/faq.shtml
According to paleontologist Bill Hammer:
?Dinosaurs became extinct at the end of the Cretaceous period,
approximately 65 million years ago. While some scientists think a
large asteroid killed off the dinosaurs (also known as the impact
theory), many paleontologists feel that climate change due to a drop
in sea level might have been responsible. I think the extinction
question is still unresolved, but I am not a strong believer in the
impact theory.?
According to paleontologist Don Lessem:
?The truth is, we don't what caused dinosaur extinction and it might
have been a combination of things like asteroids, volcanoes, gradual
climate changes, and even disease.?
According to paleontologist Tim Rowe:
?The latest news flashes from the journal Science point to volcanic
eruption as an important mechanism in mass extinctions. One group of
scientists has discovered that there was a huge episode of eruption in
what is now Siberia at the beginning of the Mesozoic - a time in
earth's history when there was an extinction even greater than the one
at the end of the Mesozoic that killed many of the dinosaurs. A second
group of scientists has looked at the recent death of some coral reefs
and discovered that volcanic dust from an eruption far away was
responsible.?
Scholastic Inc. http://teacher.scholastic.com/researchtools/articlearchives/dinos/extinct.htm
?There are dozens of theories to explain a probable cause or causes.
Throughout the Mesozoic Era, individual dinosaur species were evolving
and becoming extinct for various reasons. The unusually massive
extinction at the end of the Cretaceous exterminated the last of the
dinosaurs, the flying reptiles, and the large swimming reptiles, as
well as many other marine animals. There is now widespread evidence
that a meteorite impact was at least the partial cause for this
extinction. Impact craters are visible on most planets in our solar
system. A spectacular example of this was witnessed in 1994, when
Jupiter was struck by a series of cometary fragments. Some of these
impact blasts were larger than the Earth's diameter. Other factors
such as extensive release of volcanic gases, climatic cooling (with
related changes in ocean currents and weather patterns), sea-level
change, low reproduction rates, poison gases from a comet, or changes
in the Earth's orbit or magnetic field may have contributed to this
extinction event.
USGS Information Services: Dinosaurs
http://pubs.usgs.gov/gip/dinosaurs/
?The dinosaurs went extinct about 65 million years ago, at the end of
the Cretaceous period, which was a time of high volcanic and tectonic
activity. There are a lot of theories why the extinction occurred. The
most widely accepted theory is that an asteroid impact caused major
climactic changes to which the dinosaurs couldn't adapt.?
Enchanted Learning: Dinosaurs
http://www.enchantedlearning.com/subjects/dinosaurs/allabout/
Here you will find books, web sites and other materials about dinosaur extinction.
http://infozone.imcpl.org/kids_path_dinosaur_extinction.htm
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Read more about the history of dinosaurs here:
http://www.lsmsa.edu/MKhandoker/environmental%20science/Evolution/History%20of%20Dinosaurs.htm
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Search strategy:
Dinosaurs
Eating habits, carnivores, herbivores
Species
Habitat
Extinction, theories
I hope you find this information helpful!
Best regards,
Bobbie7 |
