Question 1
Why many plants they develop and become extinction during the Devonian period?
Question 1
Why many plants they develop and become extinction during the Devonian period?
The Devonian period took place during the Paleozoic era, and lasted from 416 to 359.2 million years ago. Plants were abundant in the Devonian because of the warm climate. The following are the reason for development of plants during Devonian period
Warm temperature, Life on land was good for plants because of the warm temperature. The climate during the Devonian Period was very warm, due to the continents being located near the equator.
Development of Vascular tissue, They developed the ability to carry food and water through the use of vascular tissues.
Production of Seeds, Plants also developed the use of seeds during the Devonian. Because of that development, plants can now reproduce without being in the presence of water.
The Devonian Period ended with a mass extinction, 364 million years ago. Extinction occurs when the last existing member of a given species dies In other words…there aren’t any more left...
Extinction: The loss of a species from the biota; the failure of a taxonomic group to produce direct descendants, causing its worldwide disappearance from the record at a given point. Plants become extinction During the Devonian period due to the following factors
Genetics Through Mutations causes a flux in natural selection, beneficial genetic traits are overruled and Loss of Genetic Diversity caused Shallow gene pools promotes massive inbreeding.
Demographics due to Small populations caused increased risk of extinction.
Toxicity Kills off species directly through food/water and indirectly via sterilization. Also can occur in short spans (a single generation) or can occur over several generations due to increasing toxicity and Increasing competition for habitat resources.
Destruction of Habitat, Elimination of living space caused Change in habitat Rainforest to pasture lands Leads to diminishing resources also Increases competition can be caused by natural processes such Volcanoes, floods, drought, etc…
Predation Introduction of predators caused Competition because some species can eat other species while others are transported by humans such as Cattle, rats, zebra mussels, etc…
Disease Epidemics Can wipe out entire species example Frog with fungus disease Killing frogs and other amphibians
Co extinction The loss of one species leads to the loss of another this cause Chain of extinction Can be caused by small impacts in the beginning a predator loses its food source which is affected by interconnectedness in nature.
Acid Rain Kills acid intolerant species
Human Causes of Extinction Increased human population, Destruction/Fragmentation of habitat, Pollution Climate change, Changes in the climate always results in changes in the biota; sudden (in geologic time) and profound changes nearly always result in mass extinction events. Gradual changes usually result in a displacement of the biota but not necessarily mass extinction Example in the Americas—80% of large animals became extinct around the same time as first human presence there
REFERENCES
http://geology12-7.wikispaces.com/file/view/The+Devonian+Period.ppt Retrieved on 28th march 2015
http://people.uwec.edu/jolhm/EH4/Extinction/Extinction.ppt Retrieved on 27th march 2015
Dutta, A.C. 1999. Botany for Degree Students. Oxford University Press, Calcuta.
Pandey, SN; Trivedi, PS and Misra, SP. 1996. A text book of botany. Vol I. Vikas Publishing House PVT
