After mating, the female then builds a nest elsewhere to raise the young alone. Franco Atirador Stephen J. Gould argued that these enormous antlers, which required great mineral resources from plants to support and prevented the elk from navigating through forests, were largely responsible for their extinction. The positioning of the antlers were poor for combat between males, but were great for intimidating rivals and impressing females. Bird-of-Paradise Bird of Paradise These birds have evolved a wide variety of plumage displays for the sole purpose of attracting a mate. Duck genitalia and mechanical barriers Credit: Clark1,2 and Richard O. Prum Ducks copulate through rape. As a result, females have evolved mazelike vaginas, complete with dead-ends to prevent insemination. Aphids go from asexual to sexual in times of stress.
The Radiometric Dating Game Radiometric dating methods estimate the age of rocks using calculations based on the decay rates of radioactive elements such as uranium, strontium, and potassium. On the surface, radiometric dating methods appear to give powerful support to the statement that life has existed on the earth for hundreds of millions, even billions, of years. We are told that these methods are accurate to a few percent, and that there are many different methods.
We are told that of all the radiometric dates that are measured, only a few percent are anomalous. This gives us the impression that all but a small percentage of the dates computed by radiometric methods agree with the assumed ages of the rocks in which they are found, and that all of these various methods almost always give ages that agree with each other to within a few percentage points.
Minerals with high blocking temperatures that form only at high temperatures are especially valuable.
Hydrogen discharge tube Deuterium discharge tube Hydrogen H is the chemical element with atomic number 1. At standard temperature and pressure , hydrogen is a colorless, odorless, nonmetallic , tasteless, highly flammable diatomic gas with the molecular formula H2. With an atomic mass of 1. Elemental hydrogen is relatively rare on Earth , and is industrially produced from hydrocarbons such as methane, after which most elemental hydrogen is used “captively” meaning locally at the production site , with the largest markets almost equally divided between fossil fuel upgrading, such as hydrocracking , and ammonia production, mostly for the fertilizer market.
Hydrogen may be produced from water using the process of electrolysis , but this process is significantly more expensive commercially than hydrogen production from natural gas. Hydrogen can form compounds with most elements and is present in water and most organic compounds. Helium Helium discharge tube Helium He is a colorless, odorless, tasteless, non-toxic, inert monatomic chemical element that heads the noble gas series in the periodic table and whose atomic number is 2.
The sun, moon, and stars 2. The fish and the birds 3. The fertile earth 6. The land animals and humans 7.
As Collins says, unless there are other indications to the contrary, the proper conclusion to draw from the phrase “A fathered B” is that “A fathered an ancestor of B”.
Herbchronology Dating methods in archaeology[ edit ] Same as geologists or paleontologists , archaeologists are also brought to determine the age of ancient materials, but in their case the areas of their studies are restricted to the history of both ancient and recent humans. Thus, to be considered as archaeological, the remains, objects or artifacts to be dated must be related to human activity.
It is commonly assumed that if the remains or elements to be dated are older than the human species, the disciplines which study them are sciences such geology or paleontology, among some others. Nevertheless, the range of time within archaeological dating can be enormous compared to the average lifespan of a singular human being. As an example Pinnacle Point ‘s caves, in the southern coast of South Africa , provided evidence that marine resources shellfish have been regularly exploited by humans as of , years ago.
It was the case of an 18th-century sloop whose excavation was led in South Carolina United States in Dating material drawn from the archaeological record can be made by a direct study of an artifact , or may be deduced by association with materials found in the context the item is drawn from or inferred by its point of discovery in the sequence relative to datable contexts. Dating is carried out mainly post excavation , but to support good practice, some preliminary dating work called ” spot dating ” is usually run in tandem with excavation.
Dating is very important in archaeology for constructing models of the past, as it relies on the integrity of dateable objects and samples. Many disciplines of archaeological science are concerned with dating evidence, but in practice several different dating techniques must be applied in some circumstances, thus dating evidence for much of an archaeological sequence recorded during excavation requires matching information from known absolute or some associated steps, with a careful study of stratigraphic relationships.
In addition, because of its particular relation with past human presence or past human activity, archaeology uses almost all the dating methods that it shares with the other sciences, but with some particular variations, like the following: Written markers[ edit ] Epigraphy — analysis of inscriptions, via identifying graphemes, clarifying their meanings, classifying their uses according to dates and cultural contexts, and drawing conclusions about the writing and the writers.
Numismatics — many coins have the date of their production written on them or their use is specified in the historical record. Palaeography — the study of ancient writing, including the practice of deciphering, reading, and dating historical manuscripts.
The isochron method Many radioactive dating methods are based on minute additions of daughter products to a rock or mineral in which a considerable amount of daughter-type isotopes already exists. These isotopes did not come from radioactive decay in the system but rather formed during the original creation of the elements. In this case, it is a big advantage to present the data in a form in which the abundance of both the parent and daughter isotopes are given with respect to the abundance of the initial background daughter.
The incremental additions of the daughter type can then be viewed in proportion to the abundance of parent atoms.
From the standpoint of a limited concordism, there are a number of factors to be kept in mind.
Classification of volcanic and hypabyssal rocks Owing to the aphanitic texture of volcanic and hypabyssal rocks, their modes cannot be readily determined; consequently, a chemical classification is widely accepted and employed by most petrologists. One popular scheme is based on the use of both chemical components and normative mineralogy. Because most lay people have little access to analytic facilities that yield igneous rock compositions , only an outline will be presented here in order to provide an appreciation for the classification scheme.
The subalkaline rocks have two divisions based mainly on the iron content, with the iron-rich group called the tholeiitic series and the iron-poor group called calc-alkalic. The former group is most commonly found along the oceanic ridges and on the ocean floor; the latter group is characteristic of the volcanic regions of the continental margins convergent, or destructive, plate boundaries; see below Forms of occurrence: In some magmatic arcs groups of islands arranged in a curved pattern , notably Japan, both the tholeiitic and calc-alkalic series occur.
The alkaline rocks frequently occur on oceanic islands usually formed during the late stages of magma consolidation after tholeiitic eruptions and in continental rifts extensive fractures. Based on the relative proportions of soda and potash, the calc-alkalic series is subdivided into the sodic and potassic series. Chemically the subalkaline rocks are saturated with respect to silica; consequently, they have normative minerals such as orthopyroxene [Mg Fe 2 Si 2 O 6] and quartz but lack nepheline and olivine in the presence of quartz.
This chemical property also is reflected in the mode of the basic members that have two pyroxenes, orthopyroxene and augite [Ca Mg, Fe Si2O6], and perhaps quartz. Plagioclase is common in phenocrysts, but it can also occur in holocrystalline rocks in the microcrystalline matrix along with the pyroxenes and an iron—titanium oxide phase.
At the time that Darwin’s On the Origin of Species was published, the earth was “scientifically” determined to be million years old. By , it was found to be 1. In , science firmly established that the earth was 3.
Overall, the geologic time scale is in great shape.
Some are too scarce such as helium.
Additionally, as the early church fathers —Tertullian, Jerome, Ambrose, Cyril of Jerusalem, Augustine, and others —emphasized, a major theological purpose of the flood story is the encouragement of moral conduct.
This is why, inclusive of the fall and the tragedy of human sin and its trans-temporal consequences, Creation is not just good, but very good Genesis 1:
On another point, if we can detect minerals that were not molten with the lava, as has been claimed, then this is one more reason why there should be no anomalies, and radiometric dating should be a completely solved problem.