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how is possible that many genetic mutations have no impact on an organism?
'By adapting to water, early whales gained access to an environment closed to most other mammals, rich in food and shelter, and short on competitors and predators—perfect conditions for an evolutionary explosion. What followed was a starburst of idiosyncratic experiments in being a whale...' What macroevolutionary pattern is described here?
It's ludicrous to suggest that humans could have evolved just through chance!
Besides, no one was around to see it happen, and no one has ever seen any organism actually evolve.
Yes, but you wouldn’t expect them to die in chronological order according to when they existed. Different layers of rock show different fossils of species that lived during that time period. The oldest species (the more simple species) are at the bottom, and they become more complex as we move up the layers (move forward in time).
All the fossil record tells us is that lots of plants and animals died in the past, which is exactly what you would expect to happen during a global flood.
Evolution does not have a drive to perfection. They evolved in stages as they adapted to their environment. Evolution gets rid of detrimental traits; it doesn’t invent new ones when needed.
And come on, how is it possible for something like the human eye or the whale blow-hole to evolve in stages, like evolution would require, given that neither one of those structures would serve any purpose until it is fully formed?!
We didn’t evolve from apes. Apes and humans share a common ancestor who is now extinct. Excant, living, species cannot evolve from other living species.
And if we really evolved from apes, why are there still apes around today?
Scientists have different theories about evolution, but they all agree that it exists. In fact, 99.85% of scientists agree that evolution exists and that it is the best explanation for the diversity of life.
Scientists all over the world disagree about evolution.
These alternative explanations cannot be tested. Science must be testable, natural, and obey the laws of chemistry and physics. We would not accept supernatural explanations in other aspects of our life. For example, if we visited the doctor for the flu and they diagnosed us as having a demon, we would not accept this as a correct diagnosis.
So what's wrong with 'teaching the controversy' and including alternatives, such as creationism or intelligent design, in the science curriculum at school?
Not all scientists are atheists. Just because supernatural causes are ruled out in science doesn’t mean that they are ruled out in regular life. The same ‘argument’ could be made that lawyers are atheists, because they don’t accept supernatural excuses for someone who commits a crime. Scientists do not accept supernatural causes simply because they cannot be tested, and science must be testable.
After all, I'm a Christian; my faith is important to me, and it's unreasonable for scientists to expect me to give it up just because they are all atheists.
it takes proteins—as well as the in- formation now stored in DNA—to make proteins. because RNA may have become able to copy themselves—to reproduce—with- out the need for proteins
RNA as a blueprint to make proteins could have existed independently at first. Later on, DNA could have appeared as a more permanent form of storage, thanks to its superior chemical stability.
The structures that translate RNA into proteins are hybrid RNA- protein machines, and it is the RNA in them that does the catalytic work. Thus, each of our cells appears to carry in its ribosomes “fossil” evidence of a primordial RNA world
ribose is unstable and rapidly breaks down in an even mildly alkaline solution. Phosphorus is abundant in the earth’s crust but mostly in minerals that do not dissolve readily in water, where life presumably originated
the team mixed the starting ingredients together, along with phosphate. A complex web of reactions—with phosphate acting as a crucial catalyst at several steps along theway— producedasmallmoleculecalled 2-aminooxazole, which can be viewed as a fragment of a sugar joined to a piece of a nucleobase. exposure to ultraviolet light—intense solar UV rays hit shallow waters on the early earth— destroys the “incorrect” nucleotides and leaves behind the “correct” ones
1. ribozymes that can catalyze the copying of relatively short strands of other RNAs: RNA has the raw
catalytic power to catalyze its own replication.
2. once a double strand had formed, separation of the strands would allow the complement to serve as a template for copying the original strand.
made of fatty acids and contained RNA (or something similar to it) and little else and replicated their genetic
material without enzymes.
mutualism: a symbiosis in which both organisms benefit
commensalism: a symbiosis in which one organism benefits without helping or harming the other
parasitism: a symbiosis in which one organism benefits at the expense of the other
as biting is risky, the probability that the mosquito survives the parasite’s development to the transmissible sporozoite stage is increased during early pre-sporozoite development
Each day the scientists chose three children to participate in the study: one who was uninfected, one infected with the asexual (non-infective) stage of the malaria parasite, and one harbouring the parasite’s gametocyte. mosquitoes were released form a central chamber and allowed to follow their preferred odor to one of the three rooms (all attached by PVC tubing)
scales, mucus and tissue from their clients. This is considered commensalism or parasitism because the removal of these things from the clients can have a negative impact. If the cleaners remove any non-ectoparasitic material then they are categorized as commensalism/parasitism (client is unaffected or harmed respectively)
comparisons of levels in vegetation beside a salmon stream with control plants nearby without access to salmon provides a direct measure of the contribution of salmon-derived nitrogen to the plants. isotopic data.
What else do the cleaners feed on and why is this considered commensalism or parasitism?
Cleaner fish can cheat by removing client scales, mucus and tissue from their clients. This removal of non-ecoparasitic material may have a negative impact on a client, thus pushing individual interactions closer to commensalism or parasitism.
What determines how the interaction is categorized?
If the cleaners remove any non-parasitic material then they are categorized as a commensalism/parasitism (client is unaffected or harmed respectively).
Why is feeding on non-parasitic material by gobies considered 'cheating' or 'dishonest cleaning?'
They remove the scales, tissues and mucus that are essential to that organisms health/survival. Instead of only removing parasites (beneficial to both) they now cause either a neutral or detrimental relationship.
According to the authors, under what conditions are gobies prone to 'cheating?'
Locally low parasite availability promotes the cleaner fish to cheat.
Variation in the benefit of being cleaned and variation in the cost of being cleaned.
Biting is risky and the probability that the mosquito survives the parasite’s development to the transmissible stage is increased during early pre-sporozoite development.
The authors present evidence that people infected with the transmittable stage of malaria are more attractive to mosquitos than are uninfected people or people with young malarial parasites. How did they acquire this evidence?
Each day the scientists chose three children to participate in the study: one who was uninfected, one infected with the asexual (non-infective) stage of the malaria parasite, and one harboring the parasite’s gametocytes (the stage transmissible to mosquitoes). Mosquitoes were released from a central chamber and allowed to follow their preferred odor to the one of the three rooms, all which were attached by PVC tubing. Children harboring gametocytes attracted about twice as many mosquitoes as the other two classes of children.
How did the authors control for the possibility that the infected people attracted more mosquitos simply because their personal body odors are attractive to mosquitos (rather than because of the presence of the parasite)?
Did the same test but gave all the children the anti-malarial treatment. The attractiveness was similar between the three classes of children. This ruled out the bias since they were all equally attractive, even the one’s who previously did host the gametocyte.
Evolutionary arms race, fewer odors by human, mosquitoes will get better at detecting tiny amounts of odor.
Why is there nitrogen from salmon found in trees?
Bears catch salmon and bring them into the woods to eat, they consume half and birds and other scavengers as well as bugs and other decomposers eat the rest. Animal waste also transfers the nitrogen throughout the environment, making it accessible to the trees in the area.
The scientists determined that up to 40% of the nitrogen in the trees came from salmon. How did the scientists calculate this number?
The contribution of salmon –delivered nitrogen to plants was directly measured by assessing a nearby control plant without access to the salmon. Isotopic data was also used to calculate how much of the N15 nitrogen isotope was found in the trees.
'Our research over the last decade...has yielded previously unrecognized linkages between the open ocean and forests and these may be important to our understanding of forest ecosystems.' Explain what the author means by this statement, i.e., what is the link between the ocean and the forest, and how might this link be critical to forest ecosystems?
Nutrient cycling can be linked between the forest and oceans. The link is critical because 40% of the tree’s nitrogen comes from the salmon allowing the costal forest to survive in these areas.
Cows, birds that bring things to different islands, bats, bald eagles, and anything that migrate seasonally.
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