Post them here!
If there is something you have a question about for things in chapters 13-15, post them here. I will either answer the questions or direct you to where you can find the answer in your book or online.
Why set this up? So your peers can learn from the questions you ask.
Questions will be answered on this post through Wednesday 2.25.09 at 9pm.
10 comments:
I get how certain conditions lend to adaptations, but how do (most) new environmental conditions not just
'bottle neck' a population? Where is the line?
Question: I get how certain conditions lend to adaptations, but how do (most) new environmental conditions not just
'bottle neck' a population? Where is the line?
Answer: The wording on the question is a little confusing, but I'll do my best to answer it. A couple of points need to be addressed in this question.
1. Environmental conditions do not lend themselves to adaptations. "An adaptation is a feature produced by natural selection for its current function." For more on defining an adaptation read: http://evolution.berkeley.edu/evolibrary/article/0_0_0/misconcep_06
2. "Population bottlenecks occur when a population's size is reduced for at least one generation" (Berkley Evolution). Causes of bottlenecks can be over hunting like you read about in the Northern Elephant Seal population or the result of a sudden catastrophic event like disease or natural disaster.
3. Over time environmental conditions can select for traits that are more favorable.
Hope that helps!
What is the timeline of the evolution we have learned about? What happened first, the mudslide catching all of the little water creatures, or the whales becoming water animals? I guess I could just use a chronology of events, please.
thanks
Could you please explain questions 4, 33 and 41 from the Quiz.
4) Scientists generally agree that heterozygous advantage is...
11) Sickle cell anemia is caused by a change in the amino acid sequence of the two beta chains in the hemoglobin molecule. How many amino acids have been changed in each beta chain, compared to normal hemoglobin?
41) Mutations tend to have little effect on the allele frequency in a population.
Thanks
Question:What is the timeline of the evolution we have learned about? What happened first, the mudslide catching all of the little water creatures, or the whales becoming water animals? I guess I could just use a chronology of events, please.
Answer: You can view an interactive time line of events here:http://evolution.berkeley.edu/evolibrary/article//evo_13# Roll the mouse of over the pictures and you will get a description. Also, on page 296 in your book there is a table with all of the eras, how long ago they were and what life existed.
Go here: http://www.pbs.org/wgbh/evolution/humans/humankind/index.html for human evolution.
The water mud slide is what has left the Burgess Shale, from the middle Cambrian Era and preserved some of the first soft bodied organisms, so yes, Burgess Shale and then later on whales.
Question:
4) Scientists generally agree that heterozygous advantage is...
Heterozygote advantage is that individuals that are heterozygous have a great reproductive success than organisms that are homozygous. Continue you reading on page 274, the top of the right column.
11) Sickle cell anemia is caused by a change in the amino acid sequence of the two beta chains in the hemoglobin molecule. How many amino acids have been changed in each beta chain, compared to normal hemoglobin?
One. Sickle cell anemia is caused by a single base pair mutation, which would result in only one amino acid being changed. See page 201 (in the check in question)
41) Mutations tend to have little effect on the allele frequency in a population.
The number of alleles in a population is much greater than the number of mutations that would ever occur. Mutations can occur on an organism by organism basis, this is very slow and small compared with the effects that migration or a bottleneck would have on the population
i tried looking at the pbs site...but is was not very helpful
i don't think i have the right answer for some of these questions
what is sexual dimorphism?
what is the difference between behavioral traits and physical traits?
Can you explain how polyploid cells are formed and why they are important?
Question:i tried looking at the pbs site...but is was not very helpful
i don't think i have the right answer for some of these questions
what is sexual dimorphism?
what is the difference between behavioral traits and physical traits?
Answer: Sexual dimorphism is the distinction between males and females. This is a vocab word from page 277 in the book. A behavioral trait is something that an organism does, a particular mating song or display. A physical trait is the phenotype, for example, how peacock's have long colorful tail feathers.
Question: Can you explain how polyploid cells are formed and why they are important?
Answer: Polyploid cells result when meiosis fails to occur properly during gamete formation; instead the cells divide by mitosis. Plants can self fertilize and when this happens the zygote is tetraploid. If the number of chromosomes in a somatic cell is 2, then the gametes should be 1. In polyploid cells, the gametes end up with 2 chromosomes each and when they form a zygote the total number is four chromosomes (tetraploid). The creation of a tetraploid plant is an instantaneous speciation event: a new species, reproductively isolated from its parent species, is produced in one generation.
This information is from the left column on page 288
Post a Comment