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Evolution
The scientific theory according to which populations change gradually through a process of natural selection.
5,264 Questions
Is ecological isolation a prezygotic isolating mechanism?
Sure is. How can one mate if an ecological barrier is erected between two biological species? Even something as simple as the time of day can be a barrier to mating.
What are some environments in which external fertilization can occur?
Water would be the number one choice.
What do humans have that show you evolved from animals with tails?
A coccyx, which is the vestigial tail in humans that sometimes grows in some rare cases.
Biogeography.
How do you debunk creationism?
The following are some of the current methods regularly used in attempts to debunk creationism:
1. Suppression- don't allow creationism (or any ideas though to be critical of evolution) to be taught, promulgated or put forward anywhere. This type of activity has been documented by Dr Jerry Bergman in "Slaughter of the Dissidents" and by Ben Stein in his documentary "Expelled".
2. The use of insults, put-downs and other dubious tactics, obviously doesn't deal with the issues but do intimidate some into silence.
3. Use of faulty argumentation such as "knocking down a straw man." Misrepresenting creationist views (creating a straw-man argument in which no creationist believes) in such a way that makes it easy to refute. One of the most common is the assertion that creationists believe in fixity of species and deny natural selection, neither of which is true. Species do change and creationists acknowledge it and have explained it.
Switching the meaning of terms is another common tactic used to debunk creationism, such as likening all change (which creationists also acknowledge) to evolution, whereas it is the 'type of change' that is the difference.
4. Ignoring History: Modern science, even scientific thought itself, flourished where there existed belief in an orderly universe, as in nations where Christianity had a strong influence. Great scientists from the past such as Newton and Kepler sought to 'think God's thoughts after him' in their scientific research. Attempts to debunk creationism regularly include suggestions that it is 'anti-science.'
A New Approach that would be successful in debunking creationism would be one that deals with rather than avoids all the key arguments put forward by creationists such as: Carbon 14 in diamonds, which should not exist if the diamonds are anywhere near as old as claimed.
Genetic entropy- the genome of all multicellular life including humans is gaining around 100 mutations per person per generation (an average estimate), leading in a relatively short time to genetic meltdown and evidenced by the literally hundreds of Mendelian genetic diseases evident today. Thus if we are as old as evolution claims, we should not exist.
The information issue -how does the new and massive amount of new information get added into the genome for a microbe to change into a man?
The origin of life issue- science has shown it is impossible to create life from lifeless chemicals.
To date such an approach remains unused.
What keeps Chinese people looking Chinese?
Inasmuch as the appearance (phenotypical manifestation) of Chineseness is genetically determined, the fact that such an appearance is not deleterious in terms of reproductive fitness means that there is no selection pressure tending to remove the genotypical determinants of the phenotypical appearance of Chineseness.
Why does evolution produce homologous structures?
Evolution works by tinkering with what is already there. It is far more likely that an advantageous change to an existing structure can occur than a gross change providing an advantage.
An example would be the transition from fishes to amphibia. Small incremental modifications to fins to provide some of the functionality of walking limbs are far more likely to occur than limbs suddenly sprouting from a body where there was nothing there before, which would be nigh-on impossible.
Which archipelago in ecudor provided the inspiration for Charles Darwin's theory for evolution?
The Galapagos Islands.
Why are vestigial proof of evolution?
Evidence, not proof. Scientists do not prove things.
Your coccyx for one bit of evidence, This is the " stump " of a vestigial tail that is now used for another purpose in humans; to help with sitting. Sometimes this tail does grow out in child development. This is evidence of the concept of evolutionary common ancestry.
When Darwin published his theory of evolution one strength of his work was?
The '' strength '' that really got it across to both scientists and lay people was the way he laid out his first chapter on artificial selection. People could progress from that fact of everyday life to natural selection much more easily than it could have been otherwise. Darwin deliberately wrote the book this way; '' one long argument. ''
How did Raymond dart contribute to evolution?
Discovered the Taung Child. One of the most important discoveries EVER! (in regards to evolution)
What are the four pieces of evolution?
1. Evolution reproduced in the lab or documented in nature:
a. Two strains of fruit flies lost the ability to interbreed and produce fertile offspring in the lab over a 4-year span ... i.e. they became two new species. (Easily repeated experiment.)
b. A new plant species (a type of firewood), created by a doubling of the chromosome count from the original stock (Mosquin, 1967).
c. Multiple species of the house mouse unique to the Faeroe Islands occurred within 250 years of introduction of a foundation species on the island.
d. Formation of 5 new species of cichlid fishes that have formed in a single lake within 4,000 years of introduction of a parent species.
2. Fossil evidence - (So much to list). The way fossils appear in the layers of rock always corresponds to relative development ... more primitive creatures in lower (older) layers. Absolute dating of fossils using radiometry. Constant discovery of new transitional forms. E.g. reptile-birds, reptile-mammals, legged whales, legged sea cows.
3. Genetic evidence - E.g. the fact that humans have a huge number of genes (as much as 96%) in common with other great apes ... and (as much as 50%) with wheat plants. The pattern of genetic evidence follows the tell-tale patterns of ancestral relationships (more genes in common between recently related species, and fading the further back in time).
4. Molecular evidence - These are commonalities in DNA ... which is separate from genetic commonalities ... much of our DNA does not code for genes at all. But random mutations (basically 'typos') enter into DNA at a known rate over the centuries. This is called the 'molecular clock' and again gives excellent evidence of when humans diverged from other apes (about 6 million years ago, according to this molecular clock), and this corresponds perfectly with when these fossils first appear in the fossil record (using radiometric dating).
5. Evidence from proteins - Proteins - E.g., things like blood proteins (the things that give us our A, B, O blood typing and the Rh factor (the plus/minus thing) which incidentally stands for 'rhesus monkey'); the exact structure of the insulin molecule; and my favorite, the proteins responsible for color vision. The specific proteins found in human color vision are exactly the same as those found in Old World primates (the great apes and the monkeys found in Africa and Asia). These proteins are absent in New World primates (the Central and South American monkeys), and from all other mammals. In fact among the New World primates, only the howler monkey has color vision ... but these use slightly *different* proteins, coded on different locations and chromosomes, than humans and the OW primates. This is yet more evidence of a closer link between humans and the OW primates.
6. Vestigial and atavistic organs - E.g. Leg and pelvic bones in whales, dolphins, and some snakes; unused eyes in blind cave fish, unused wings in flightless birds and insects; flowers in non-fertilizing plants (like dandelions); in humans, wisdom teeth, tailbones, appendix, the plantaris muscle in the calf (useless in humans, used for grasping with the feet in primates).
7. Embryology - E.g. Legs on dolphin embryos; tails and gill folds on human embryos; snake embryos with legs; marsupial eggshell and carnuncle.
8. Biogeography - The current and past distribution of species on the planet. E.g. almost all marsupials and almost no placental mammals are native to Australia ... the result of speciation in a geographically isolated area.
9. Homology - E.g. the same bones in the same relative positions in primate hands, bat wings, bird wings, mammals, whale and penguin flippers, pterosaur wings, horse legs, the forelimbs of moles, and webbed amphibian legs.
10. Bacteriology, virology, immunology, pest-control - I.e. the way that bacteria evolve in response to antibiotics (we can compare strains of tuberculosis today, with samples of older epidemics and can see the specific structures), or viruses (like HIV) respond to antivirals, or insects evolving in response to pesticides.
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P.S. to Alana:
1. Evolution has absolutely NOTHING to do with "chemicals miraculously appearing out of thin air." Nothing. Nada. Zip. Niente. Ixnay.
2. Charles Darwin never said anything of the sort.
Whenever a Creationist starts a sentence with "Even Charles Darwin said ..." you can be sure that the very next words are something Charles Darwin never said.
Lyell collected overwhelming evidence that the Earth's surface is constantly changing and did much to advance the idea that the Earth changes through time (inorganic evolution). Lyell also put forth the idea that changes from one rock layer to another may take millions of years, which indicated that Earth much older than was previously thought.
What are the characteristics of the sociolinguistic theory?
The sociolinguistic theory focuses on the relationship between language and society. It emphasizes that language use is influenced by social factors such as social class, gender, ethnicity, and culture. The theory also recognizes that language variation and change are natural and result from social interactions and linguistic choices made by individuals or communities. Additionally, it highlights the importance of studying language in its social context and the role of power and identity in language use.
Why did humans leave the trees?
Answer 1
Humans did not leave the trees for the simple reason that they were never in the trees to start with.
Our forefathers, ape-like creatures, eventually left the trees most likely because they 'learned' to walk up-right, use bones and stones as tools and weapons and caves for shelter. Since there was no longer an advantage in being able to climb trees and life there, we simply lost that ability.
Other animals have experienced similar adaptations. The Kakapo for example is a kind of parrot which lives solely in New Zealand and which has lost the ability to fly for the simple reason that it did not have any enemies, no predators which could attack and eat it. It therefore did not need the ability to fly away when attacked and as a result, it lost that ability.
There is a very interesting video of a talk by Douglas Adams recorded at the University of California in which he describes the interesting and evolutionary adaptations of the Kakapo and other animals. The video is nearly 90 minutes long but educational and very funny. See link below in Related Links.
Answer 2
There are various hypotheses explaining what might have driven the ancestors of H. sapiens to adapt to a life in the plains rather than in and amongst trees. One is that a climatological chance slowly drove certain tribes of apes from their preferred habitates; another factor may be increasing population numbers and competition; it may have been simple curiosity or chance, that drove primates to try their luck at first the outskirts of their preferred habitat and then beyond them. Frankly, I doubt we'll ever know with any certainty what, out of a million possibilities, brought our ancestors from the trees.
What is the idea that species originate through a gradual change of adaptations?
The theory of evolution by natural selection. Called gradualism.
What are the different kinds of Era?
This three eras was included in the Proterozoic Eon.The first Era was the Paleoproterozoic Era;next is the Mesoproterozoic Era;then the last is the Neoproterozoic Era.
This another three eras was according to the Phanerozoic Eon.The first Era was the Paleozoic Era;followed up by the Mesozoic Era;then the lastly was the Cenozoic Era.
How does domain Eukarya differ from domain Bacteria and domain Archaea?
Eukarya has a doubled walled nucleus containing the genetic material and Bacteria and Archaea do not have contained genetic material. Eukarya has membrane bound organelles and the other two Domains do not. These are the pertinent differences.
When did Darwin explain his theory of evolution?
November 24, 1859. The day his book "On the Origin of Species" was released.
