The answer is thirteen.
STR stands for <u>s</u>hort <u>t</u>andem <u>r</u>epeats. In this analysis, highly polymorphic regions with short tandem repeats are used. In FBI investigation, thirteen regions are analyzed and compared. The chance for two people to have the exact same thirteen regions is almost impossible (1 : 1 billion or less). This way a difference between two DNA profiles could be assessed.
All evolutionary changes that allow a species to change in response to the environment, are originally a result of beneficial DNA mutations.
Beneficial genetic (DNA) mutations are result in individuals with special characteristics that allow them to survive better in the environment so they pass their genes to the next generation.
Here's a fictional example I made just for you!: Lets say you have an alien species called Hibas. They are jelly blobs that float around, don't move, and open their mouths to capture neon shrimps that happen to swim into their mouths. But one day a certain Hiba developed some muscles through a genetic mutation. It was able to "wiggle" through the water and steer itself instead of floating around. This allowed it to eat more neon shrimp than the other Hibas, so it grew faster and was able to reproduce faster. It's kids also had muscles and had an advantage so they reproduced faster then the other Hibas. Eventually the whole Hiba species started to have muscles because the ones that didn't weren't able to compete and did not survive as well.
The reason that most of the Hibas developed muscles was because one of them had a mutation that allowed it to have muscles. This was a BENEFICIAL mutation that allowed it to SURVIVE BETTER.
Yes, Almost ALL cells have the same DNA in a human body. This is because our DNA is inside our Nucleus. DNA is the same in every cell in a human body. Hope this helps! ~
Answer:
There is no video but ecological relationship will be defined on a general note and it is not always beneficial to organisms.
Explanation:
In an ecosystem, organisms of the same or different species tend to interact with one another. This interaction is referred to as ECOLOGICAL RELATIONSHIP between the involved organisms. An ecological relationship can be of different types depending on the effect.
SYMBIOSIS is an ecological relationship between two organisms that interact together. SYMBIOSIS can either be mutualistic (both organisms benefit), parasitic (one organism loses and one gains), or commensalistic (one organism benefits and one neither benefits or loses). Another ecological relationship is PREDATION, where one organism called the PREDATOR feeds on part or all of another organism called PREY in order to obtain energy.
As stated above, some of the organisms involved in an ecological relationship benefits while others lose. Hence, it is not always a beneficial relationship to organisms.
Am certain that the factor that prevents us from finding fossils from the Precambian era is that Most rocks from that era are deeply buried. The precambrian is the informal name for the large expanse of time preceding the current Phanerozoic Eon. It began with the Earh's Formation about 4.5 billion years ago and lasted until the advent of multicellular life about 542 million years ago.
