Chimps walk on four legs in the rainforest, while we walk upright and can send rockets to the moon.
We don't have all the answers.
Some answers can be found in the field of evolutionary developmental biology.
Major changes in body form and function can occur when some genes regulate other genes.
Different species have the same DNA sequence.
The different species might have different outcomes because the genes are up or down regulated by other genes.
Homeotic genes and Heterochrony are examples.
Homeotic genes control spatial organization of body parts.
They determine where the wings or legs will develop on an insect or where the petals will go on a flower.
The Hox gene provides information in the development of embryos.
A change in the location of two Hox genes in crustaceans will make them legs.
Heterochrony is a change in the timing of the development of body parts.
They are very similar as infants.
As the chimp matures, the face becomes more prognathic and the jaw and teeth become larger and more powerful.
The human skull seems to stop development before the same changes happen.
It is possible that the genetic code for the skull in humans and Chimpanzees is the same.
The human skull genes stop developing sooner.
The reduction and eventual loss of hind limbs in whales can be traced back to the slow growth of leg and pelvic bones.
It can change the timing of reproductive development compared to the rest of the body.
The adult aquatic salamander, the axolotl, retains juvenile structures into adulthood.
There wasn't any free oxygen in the ancient atmosphere.
The ancient atmosphere consisted of CH 4, NH 3, CO, CO 2, N 2 and H 2 O.
The primitive atmosphere probably had intense lightning and UV radiation that provided energy for chemical reactions.
Scientists are trying to figure out how the first organic molecule and earliest life developed.
Here is a synopsis of the experiments.
In the 1920s, B. S. Haldane believed that organic molecule could form under the conditions of early Earth.
Without a corrosively reactive oxygen present, organic molecules could form and remain.
In the absence of life, chemical experiments show that it is possible to form complex organic molecules.
The Oparin-Haldane hypothesis was tested in the 1950s by Stanley Miller and Harold Urey, who found that almost any energy source would have converted the molecule in the early atmosphere into a variety of organic compounds.
They used electricity to make it look like lightning and UV light were present in the early atmosphere.
Similar experiments were carried out by Sidney Fox.
He began with organic molecules and was able to produce structures that were cell-like.
The first cells on Earth were prokaryotes.
They used the surrounding primordial soup as a source of nutrition.
About 3.5 billion years ago, they probably began to evolve.
The evolution of prokaryotes took 1.5 billion years.
Lynn Margulis developed the theory of endosymbiosis, which led to the emergence of eokeryotes.
She said that the free- living prokaryotes were once inside larger prokaryotic cells.
It became permanent because of the mutually beneficial relationship.
There are a number of points that show that mitochondria and chloroplasts are endosymbionts.
There are several hypotheses about the origin of life on Earth.
Chloroplasts and mitochondria have their own genes.
The mitochondria's and the chloroplasts' genes are more similar to prokaryotic genes.
It isn't wrapped with histones.
These organelles have two different types of cells.
The symbiont was the one that belonged to the host.
The theory states that the host cell takes up the mitochondria and chloroplasts through a process called phagocytosis.
The first genetic substance on Earth is thought to have been a small, single-strandedRNA molecule.
ribozyme, a type ofRNA, can transmit information to the next generation like DNA does.
Since the discovery of ribozymes 50 years ago, the concept of RNA World has gone from speculation to a prevailing idea.
ribozymes is an exception to the idea that all biological catalysts are made up of proteins.
It is not a molecule.
Natural selection is a major mechanism in the evolution of any population.
Not every trait results because it is adaptive.
Exaptations are traits that evolve by natural selection in one context but are then co-opted for another purpose.
In the context of selection for insulation, feathers might have arisen as an adaptation, and only later were they co-opted for flight.
The general form of feathers is an adaptation for insulation and flight.
It's important to be able to date fossils accurately.
The age of a fossil is determined by using a technique called radiometric dating.
It is based on the half-life of radioisotopes.
Half-life is the amount of time required for the nucleus of a sample to decay.
Half of the original material has been replaced by a new element.
Half of the element is still intact.
As long as billions of years, half-lives can be as short as a fraction of a second.
Carbon-14 has a half-life of over 5000 years.
It has a half-life of 4.5 billion years.
Half-life is unaffected by temperature, pressure, or any other environmental conditions.
The elements that were accumulated in the organisms are contained in the fossils.
A small amount of radioactive carbon-14 and stable carbon-12 are found in living organisms.
The amount of C-12 in the tissues stays the same when the organisms dies.
The nitrogen-14 that it contained at the time of death decays into another element.
If you measure the ratio of C-14 to C-12 in a fossil, you can determine its age.
The method of carbon dating can be used for fossils up to 75,000 years old.
If a fossil is older than that, it doesn't have enough carbon-14 to be detected.
If the ancient fossils are embedded in volcanic rock, we may be able to date them.
As it cools, lava may trap radioisotopes from the surrounding environment.
If fossils are sandwiched between two layers of volcanic rock and we can date the two layers by a similar means, then we know the age range of the fossils.
If two volcanic layers surrounding fossils are determined to be 490 and 499 million years old, then we know the age of the fossils to be between 490 and 499 myo.
Determine how many half-lives have passed to get from 100.0 g to 6.25 g, divided by 2 to get 50.0 g.
Divide your original 96.4 days by 4 to get 24.1 days.
The half-life of thorium is 24.1 days.
Big ideas were covered in this chapter.
Evidence for evolution comes from various scientific fields.
Populations tend to grow and exceed their limited resources according to Darwin's theory of natural selection.
People with more favorable genes are more likely to live to produce offspring.
Fittest is defined by reproductive success, not the fastest or biggest.
The survival of a species in a changing environment depends on a diverse gene pool.
Natural selection, chance and random, nonselective events can affect the evolutionary process for small populations.
There are five conditions for a population to be in the H-W equilibrium.
These conditions are rarely met.
Simple H-W problems can be calculated.
The fitness of an organisms and of a population can be increased or decreased by certain phenotypes.
Humans alter the environment and affect the survival of other species, such as artificial selection, planting only one variety of a crop, and use of antibiotics.
Fossils can be dated using a variety of methods.
Evidence for evolution and common ancestry can be found in the similarity of front limb bones in whales, humans, and bats.
Evidence for evolution and common ancestry can be found in the chemical similarities between kingdoms.
Major features of the genetic code are shared by all organisms.
Common ancestry and speciation can be demonstrated using shared and derived traits.
The rate of evolution can vary.
In times of stress, evolution is rapid.
There are many hypotheses about the natural origin of life on Earth.
The organic molecule could have been synthesised from the organic precursors provided by Primitive Earth.
When Earth was formed, there was no free oxygen.
There have been five major extinctions.
The most common inherited disease in Caucasians is cystic fibrosis.
A calculation shows that one out of 2,500 newborn infants have the disease.
The disease is caused by an allele.
At a young age, cystic fibrosis was lethal.
People have been speculating for many years as to why the gene pool is so high.
When you have a fatal disorder, you expect the population to decrease.
This has not happened with CF.
White shells were developed by snail populations because of the light surrounding gravel.
Soon after birth, her children will be able to learn sign language.
Antibiotic-resistantbacteria are becoming more common.
According to the CDC, over 80,000 MRSA infections and 11,000 deaths occur every year.
Scientists need to find a way to make the drug stronger.
The earliest evidence of the extinct freshwater reptile was found in the early Permian period.
It never ventured onto land.
It could not have traveled across the Atlantic Ocean because it only lived in freshwater.
South Africa and Brazil are the only places in the world where the fossils of the Mesosaurus are found.
There aren't enough paleontological expeditions in other regions to find them.
The fossils have not been recognized as a species.
Brazil and South Africa are now part of the area.
The phage viruses acquire bits of the bacterium's genetic material.
In some cases, the phage transfers the bits of hostbacteria to another bacterium.
Most of Earth's organisms disappeared in five major extinctions.
The allele for agouti is dominant in a population of Netherland Dwarf rabbits.
Stanley Miller set up a closed glass system containing a mixture of gases, including H 2 (hydrogen gas), CH 4 (methane), NH 3 (ammonia), and H 2 O.
The sparks were discharged to mimic lightning.
The atmosphere was cooled by raining water and dissolved into a flask.
Miller periodically collected samples for analysis.
In the 19th century, a large lava flow spread across one of the Galapagos Islands, dividing it into two parts, the dry highlands and the lowlands.
A new species of finch evolved on those islands.
A region of central Massachusetts has had a population of moths for hundreds of years.
The colors of the tree trunks on which the moths hide match a wide variety of colors.
There is a limestone mining quarry in that region.
The air is polluted with white dust from the limestone dust.
There are four possible changes to the moth population that can be seen in the graphs below.
A bat's wing and a human's arm are very different.
Humans and bats are related.
The choices are in two parts.
The answer that includes the correct term that describes the relationship between a bat's wing and a human's arm will explain how this relationship supports the theory of evolution.
The sickle cell trait is related to race.
A person must have two alleles in order to have the disease.
There were researchers collecting data on the incidences of the disease in children under the age of 14 in Touba.
They found out that 3,942 children had the disease, while 5,909 did not.
Two populations of finches are isolated from each other on a small island in the Galapagos Islands.
One population is larger than the other.
The entire island has been attacked by a new bug that has spread quickly.
Lake Washington is similar to the Pacific coast.
It was contaminated with 20 million gallons of sewage from surrounding farms.
The water clarity was less than 2 feet by the 1960s.
In 1968, the waters of Lake Washington were cleared and the lake became a paradise for boaters.
The lake's water clarity went up to 15 feet after the clean up was done.
The stickleback is a small fish that lives in both freshwater and marine water.
In 1955, the sticklebacks in Lake Washington had up to 30 plates on their bodies to protect them from large marine predators.
When scientists began to study the fish in the lake in 1955, the freshwater species of sticklebacks had little protective armor.
Experiments with mice who carry the genes have shown that they are resistant to the disease.
According to published work, the CF gene may confer resistance to some diseases.
The information in the question doesn't make sense.
The fact that a gene is dominant has nothing to do with how common it is in the population.
If a gene is somehow adaptive or not harmful, it can remain in a population.
Choice A is determined by sudden and extreme change.
The graph doesn't tell you how fast the change happened.
Choice B is not correct because it describes stabilizing selection.
There is a graph where one population divides into two.
The most successful organisms produce the most offspring.
The best-adapted organisms are not always the largest, fastest, or smartest.
The wording implies that the snail needed to be a certain color and so it became that color.
Organisms don't evolve because they need to.
Choice C isn't correct because acquired traits aren't inherited.
The other choices are related to apes.
All non resistantbacteria die when exposed to antibiotics.
Drug companies did not change the formula.
This is just one example.
There is a lot of evidence supporting the existence of Pangaea.
The p allele, which is the dominant one, is 0.4 if q is 0.6 and p is 1.
Directional selection is when one characteristic replaces another.
There was a range of colors of snakes in the area.
Pressure from the environment was picked against different colors until only two remained.
The stem of the question doesn't say anything about feeding.
The stem of the question doesn't say anything about nested.
Pressure from the environment will cause the population of moths to change in color.
No one will change.
There are two types of moths within the population.
The dark moths will be easier to see in the new environment.
Lighter ones will be counted by researchers.
Similar underlying structures do not reflect common ancestry.
These structures are not examples of convergent evolution or parallel evolution.
There were only one species of finches on the Galapagos Islands.
Different species fill different niches.
One example of genetic drift is the founder effect.
The bottleneck effect is another one.
The whale is a mammal and the shark is a fish.
They both experience the same environmental pressures.
The design of their fins is the best for living in the ocean, not because they are related or have a recent common ancestor.
The two animals live in the same environment and are under the same pressures.
They have evolved along parallel lines.
40% of the children are afflicted.
The percentage of those without the disease that are carriers is determined by the number of ps and qs.
Individual organisms don't change because of Choice A.
The rate of occurrence of a trait is what changes.
Over time, a trait will likely spread within a population.
The theory of evolution is based on denying that populations change over time.
The number of plates on a fish can be increased orDecreased by amutation.