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Evolution
The scientific theory according to which populations change gradually through a process of natural selection.
5,264 Questions
What did Avery's theory provide evidence for?
Ostwald T. Avery's experiment was an extension of the works of Griffith's. Griffith's experiment using virulent and avirulent Streptococcus pneumoniae (which had different colony characteristics) proved that it was possible for the heat killed virulent Streptococcus pneumoniae to pass on the genetic information for formation of smooth colonies to avirulent strains. Avery, Mc Leod and Mc Carty conclusively found out that the genetic material responsible for transfer of characteristics between the strains was DNA. This was achieved by incubating the cell lysate of virulent Streptococcus with proteases, RNAses and DNAses separately before mixing it with avirulent strains. It was found that only when the lysate was incubated with DNAses did the transfer of smooth colony formation characteristic from the virulent strain to the avirulent strain fail to occur.
What is the connection of physicochemical theory to the theory of evolution?
Physicochemical theory examines the physical and chemical processes underlying biological systems, providing a framework for understanding how organisms function at a molecular level. This understanding is crucial for studying evolutionary processes, as changes in the physical and chemical properties of molecules can drive genetic variation and adaptation over generations. In essence, physicochemical theory helps to elucidate the mechanisms by which evolution occurs at a molecular level.
What is a beneficial feature that evolved by means of natural selection?
Camouflage is a beneficial feature that evolved through natural selection, as it allows organisms to blend in with their environment and escape predators. This adaptation increases an individual's chances of survival and reproductive success, ultimately leading to its increased prevalence in the population over time.
Was H G Wells against Darwin's theory of evolution?
H.G. Wells was a proponent of Darwin's theory of evolution. In his works, Wells often referenced evolution and the idea of human progress through natural selection. He was known to support and popularize Darwin's ideas in his writing.
Think of a plant that has bees as its one type of pollinator. The pollen would be taken long distances to other plants of the species and good genetic recombination would ensue from this. Also, a plant spread out like this would have many different micro environments to flourish in and the variations of this plant could do better in one of these environments.
The obvious disadvantage would be if your pollinator succumbed to some disease or other local natural disaster.
How did evolution change worldviews?
The theory of evolution proposed by Charles Darwin challenged traditional worldviews by suggesting that all living organisms share a common ancestry and are subject to natural selection. This idea shifted perceptions of human origins away from religious explanations and towards a scientific understanding based on evidence and observation. Evolution has influenced fields beyond biology, such as ethics, morality, and the nature of existence.
An ideal ecosystem is a balanced environment where various species interact with each other and their surroundings in a way that maintains biodiversity, supports ecological functions, and sustains life. It has a healthy food web, clean water and air, and stable populations of plants and animals. Human activities should aim to preserve and protect these ecosystems for the well-being of all living organisms.
Charles Darwin evolution of man theory?
According to Charles Darwin, man is an evolved species, part of the natural world. We are not in any essential way different from other mammals in the world, apart from our advanced capability for thought and self-awareness.
Is evolution the same as growth and metamorphosis?
Evolution refers to the change in genetic characteristics of a population over generations, involving mechanisms such as natural selection. Growth typically refers to an increase in size or mass of an individual organism, often controlled by hormones and environmental factors. Metamorphosis is a process some organisms undergo, involving distinct stages with different body forms, such as the transformation from a caterpillar to a butterfly.
Is Genetic diversity is the raw material for evolution?
Mutations occur randomly, and every once in a blue moon, a mutation offers some benefit to a individual of a particular species in a particular place and allows that individual to have more offspring than its peers. If the mutation provides enough benefit to some individuals, they will have a tendency to survive and reproduce (as per the principle of natural selection).
Natural selection reduces variability by killing off less fit individuals. It is mutations that increase the variability and allow evolution (successful natural selection, not mass extinction, but controlled deaths) to occur. Without variability there is no evolution.
How does natural selection produce genetic variation within a species?
It's mainly mutations in the DNA and recombination of chromosomes that produce the genetic variation. Natural selection then favors those changes that give rise to greater reproductive success.
A population in which the allele frequencies do not change from one generation to the next is said to be in equilibrium.
Number of chromosomes in a normal human body cell - or genome?
In humans there are 23 pairs, for a total of 46 chromosomes (the complete genome) in each body cell.
What determines which variations are selected for or against?
The ability of those variations to survive and be reproductively successful against other variations in the immediate selective environment. The coin evolution pays in is reproductive success.
What process forms new seafloor?
New seafloor is formed through a process called seafloor spreading, which occurs at mid-ocean ridges. Magma rises from the mantle and solidifies to create new crust as tectonic plates move apart. This continuous process results in the creation of new seafloor and plays a key role in plate tectonics.
Where on earth would you find the greatest biodiversity?
In general, biodiversity globally is high in the Tropical World
of the humid tropics (most especially in tropical rainforests where more than half of all species are found) and in the extremely infertile Unenriched World
of the ancient arid landmasses of Australia and Southern Africa. Biodiversity is much lower in the geologically young and cool Enriched World
which basically corresponds to the extratropical northern and western hemispheres, plus New Zealand (which can very easily be thought of as part of the Western Hemisphere though it is on the other side of the International Date Line).
Although it is popularly though that high biodiversity relates to the more “benign†and less demanding environment in hot climates, recent research by Michael Huston of the University of Texas in “Biological diversity, soils, and economics†and “Precipitation, soils, NPP, and biodiversity: resurrection of Albrecht's curveâ€, Australian ecologist Tim Flannery in The Future Eaters
plus Jason Weir and Dolph Schluter in “The latitudinal gradient in recent speciation and extinction rates of birds and mammals†show that these are misconceptions.
Flannery and Huston both demonstrate that owing to the roughly four orders of magnitude greater age of their soils (except in the volcanic regions of the Pacific Rim), the productivity of the Tropical and Unenriched Worlds is very much less than those of the Enriched World of the extratropical northern and western hemispheres. Weir and Schluter show that speciation rates are much lower in the Tropical World than in the depauperate fauna of the Enriched. One would presume that with their extreme geological stability the Unenriched World of Australia and Southern Africa would have still lower speciation rates than the humid tropics
. This is especially true when one considers that many birds and mammals in Australia and Southern Africa require so much labour for reproduction that most adults must serve as “helpers at the nest†rather than reproduce on their own, which acts as an extremely severe limiter on potential dispersal.
All these indicators point to the higher diversity of the Tropical and Unenriched Worlds as being due to reduced interspecific competition
compared to the young and highly productive Enriched World. Soils of an infertility universal in all of the Unenriched and most of the Tropical World are exceedingly rare in the Enriched World - occurring only in a few areas of exceptionally nutrient-poor parent materials
like ultrabasic rocks (serpentines, peridotites) - and then only outside of glaciation limits within which intrazonal parent materials are converted to highly fertile zonal soils. (In this context, it’s notable that the most northerly major biodiversity hotspot in the Klamath Basin is one of the major occurrences of serpentines in the world, as is the very rich tropical hotspot of New Caledonia).
In the Tropical and Unenriched World resources are so scarce in unfertilised environments that co-operation rather than competition tends to be the rule to allow plants to obtain the minimal nutrition possible on these soils. The absence of competition reduces extinction rates to a fraction of the level observed throughout the Enriched World: in essence, the creation of biodiversity occurs in the Enriched World, but it is rapidly pooled into reservoirs in the Tropical World, and the Unenriched retains older species (marsupials, mousebirds) dating from periods when its ecological conditions were globally general.
This process is called natural selection. It is the mechanism by which traits that provide a survival or reproductive advantage to an organism become more common in a population over time.
What are the sites of gametogenesis?
Gametogenesis occurs in the gonads (ovaries in females and testes in males). In females, oogenesis takes place in the ovaries, where oogonia develop into primary oocytes. In males, spermatogenesis occurs in the testes, where spermatogonia differentiate into sperm cells.
What did the sparks in miller and urey's experiments stimulate?
They simulated lightning in the early earth's atmosphere. The reasoning being that the reactions required some form of energy input to begin, and that lightning would have almost certainly been present.
What type of evolution studies changes in living things?
Biological evolution studies changes in living things over time, including how species adapt, diversify, and evolve through natural selection and genetic variation. It seeks to understand the mechanisms driving these changes and their impact on biodiversity and the development of life on Earth.
No, the process of speciation occurs over many generations through evolutionary changes in a population. It is not a sudden event resulting from the mating of two individuals from different species. Speciation involves gradual divergence in traits and genetic makeup that eventually lead to the formation of a new species.
Joins together the ideas of modern genetics with Darwin's theory of natural selection?
Modern genetics has provided evidence to support Darwin's theory of natural selection by showing how variations in genes can lead to differences in physical traits among individuals of a species. Genetic research has also demonstrated how the process of natural selection acts on these genetic variations to drive evolutionary changes in populations over time. By understanding how genes and natural selection interact, scientists can better explain the mechanisms behind the diversity of life on Earth as proposed by Darwin.
RNA polymerases are transcripted by which enzyme?
You seem confused. RNA polymerase is the enzyme that transcribes DNA into pre mRNA. So, the enzyme would transcribe the messenger RNA for its own protein construction.
True or false Mutations are not capable of altering allele frequencies?
In the strict sense, no. Mutations happen to individuals and are only heritable in the germ line. Populations have allele frequencies in their gene pools. So, the mutation must be beneficial, lucky enough that it original carrier passes it on intact and that it is driven into the populations gene pool in sufficient number, by having reproductive success, to change allele frequencies.
