For the chi-squared test, whether or not the answer is acceptable or not is primarily based on what significance level you are using and what critical value matches that?
So most of the time you are going to use a 5% significance level, but not always. If the critical value (p value) comes up LESS THAN the significance level than the null hypothesis is not accepted.
yes, and when we talk about this in genetics an example would be how well does the actual data (given it is a big enough set) match the theoretical prediction. It's like when we did dihybrid crosses and expected a 9:3:3:1 ratio. The Chi-square test gives us the probability of the data actually being randomly gathered. Of course you can sometimes operate on wrong assumptions too, like linked characteristics where independent assortment doesn't happen, but I'll leave that alone for now.
What is the difference between a gene pool and alleles and an example of each.
a gene pool is the collection of different genes, which usually refers to the collection of alleles. alleles are present in the genes and the gene pool is the umbrella containing it all.
Why did the beaks of the Galapagos finches change over time?
The beaks change as food sources change. For example, when there is a large amount of the food most easily eaten by large beaks then the birds with small beaks die off, and don’t reproduce, so in the next generation the large beaks are most prominent. Also, beaks change to reduce competition between finches so they can eat a variety of food sources.
Also, how can you recognize if a trait is analogous or homologous?
Homologous structures look the same but have different functions and analogous have the same function but do not share a common ancestor.
So the leg bones of a cat, the flipper of a whale, and wing of a bat are examples of homologous structures because they share a common ancestor, but needed to adapt to different functions.
Analogous structures would be like our bat wing and the wing of a bird. They do not have common ancestry (not recent at least), but their structures have the same function.
Can gene pools become acquainted again after they have undergone speciation? How?
By my assumption of your intent of acquainted meaning breeders to one another, the answer is no. Once a gene pool has diverged and becomes its own specie, reproductive incompatibility occurs. If they do become acquainted, their offspring will be infertile.
While I agree with Morsal for the most part, let's not forget that microorganisms can reintegrate some genes by consuming each other's plasmids. Instead of digesting the plasmid, they incorporate it into their system!
Also, I know Morsal was focused on nature, but we can genetically modify organisms and that could be using genes from different species. ...of plants for instance.
What is the difference in effects on species that endure gradualism vs. those that endure punctuated equilibrium?
Gradualism occurs when changes develop in a slow manner. For species to undergo gradualism, then changes would not be visible over a short amount of time, but rather a long period. Species with punctuated equilibrium tend to undergo some sort of a rapid change that causes them to form and adapt to a new equilibrium.
Species that endure gradualism have slow, continuous changes over time which leads to speciation. For example, the finches' beaks changed in length over time in order to be suitable for the environment. However, species that endure punctuated equilibrium have abrupt changes which also lead to speciation. They have long periods of stability before a period of huge change. For example, fossils have been found that provide as evidence for the change in species such as the change is snails' shells.
I think it is important to note that we can find examples of both gradualism and punctuated equilibrium in our history and often times what we call it is dependent on the time scales we are describing. I think the most important point to know is that if the environment changes in small ways, so will adaptation (Beaks of the finch), but if drastic change occurs we see major extinctions and rapid (still over long periods of time for humans) adaptation. These changes can be called naturally selective pressures.
How similar are the genes of different species? Does this reflect how different or similar the traits seem to be?
What is a clade and what is a cladogram?
A clade is a group of organisms that have evolved from the same ancestor. A cladogram is a tree diagram that shows the similarities and differences of species within clades.
Please also know that the cladogram can also shows the last common ancestor of related organisms.
What you are describing are one of the big ways we know evolution to be true. The more similar the structures, the more similar the DNA, and the more closely related organisms are.
Why is biodiversity valuable and what benefits does it provide for humans?
When you consider the fact that biodiversity contributes to the survival of a ecosystem then we know that can be very important! For example, imagine you have a very diverse region, and a change occurs to that region. The likelihood of it surviving this change are much higher than if we had low diversity. It's more complex than this like when you think of "keystone" species in an environment, but I think you can see that lower diversity means less able to handle change.
What is mitosis and meiosis? What is the difference between the two?
Hey Ms. Vasquez,
Mitosis is normal cellular division so that your body tissues can keep doing their specialized job, or to grow, or to repair.
Meiosis is the cellular division that lead to gametes (sex cells).
While mitosis produces diploid cells (2 sets of chromosomes), meiosis produces haploid cells (only one set of chromosomes).
Why are genetic diseases on the X chromosome more common in males?
Males have chromosomes XY, while females have XX. It is more common for a male to have a genetic disease on the X chromosome because they only have one of it. For example, if there is a disease that is recessive, and a male acquires it, then there is no way to cover it up because of only one X chromosome. But if a female gets it, there's a higher chance of covering the disease because of 2 X chromosomes, where a dominant allele would cover up the recessive.
I don't really understand Linked Genes
It is basically genes that are located on the same chromosome. They can be located on the X chromosome and can travel together on the same gamete or on the same autosome
Marco is right, but know what this means to offspring. The closer 2 genes are linked means that they are very close on the chromosome and likely to be passed together. This means that your typical ratios that you would expect to find (Mendel's independent assortment) often do not turn out. You typically will find a lot of 1:1 ratios.
Say there is a population that lacks genetic modification however the population of such species remains fairly constant, rarely above or below. What could be an explanation for this occurrence?
Good question. If I do not see much of a change in a population I will assume there isn't much of a change in the environment.
This is your opportunity to engage in those parts of the curriculum that are difficult for you and to help others out by digging up answer for them and posting them here. I hope that you will be a part of our community!