When a top predator is removed from an ecosystem, a series knock-on effects are felt throughout all the levels in a food web, as each level is regulated by the one above it. This is known as a trophic cascade. The results of these trophic cascades can lead to an ecosystem being completely transformed. The impacts trickle down through each level, upsetting the ecological balance by altering numbers of different animal species, until the effects are finally felt by the vegetation.
Answer:
In mosses gamete are produced by MITOSIS; In ferns gametes are produced by MITOSIS.
Explanation:
Ferns usually grow way bigger than mosses and they are both primitive plants. In ferns the gametes, sperm and eggs are formed by mitosis when there is a suitable place for development.
Answer:
The statement suggests ability of existing DNA molecule to replicate itself by the process of DNA replication. Each strand of double helical DNA can serve as template for the synthesis of new complementary DNA strand.
Explanation:
Watson and Crick proposed the double-helical structure of DNA. Accordingly, the DNA molecule is a double helical structure in which two polynucleotide chains are held together by base pairing between the complementary bases of two chains.
There are four nitrogenous bases present in DNA: adenine and guanine (purines) and cytosine and thymine (pyrimidines). Adenine always pairs with thymine and cytosine pairs with guanine base.
According to Watson and Crick, the ability of one DNA strand to base-pair with a complementary DNA strand suggests the existence of the DNA replication process. During DNA replication, each DNA strand should serve as a template to specify the nucleotide sequence of the new DNA strand.
There are a variety of points in the transcriptional chain at which it is possible to disrupt protein synthesis in bacteria. Let’s enumerate just a few:
<span>There’s the initial point where DNA is transcribed into mRNA;<span>there’s the point where mRNA binds to the Ribosome complex;</span>there’s the point where tRNA-aminoacyl pair binds to the Ribosome according to the current codon being “read out” in the mRNA;there’s the point where the aminoacid transported by the tRNA is transferred to the growing protein chain; andthere’s the point where the protein synthesis is determined complete, and the Ribosome disengages and releases the newly-synthesized peptide chain.</span>
In each of these stages (and in some other, more subtle phases) there are possible points of disruption and there are specific disruptors; some of which are indicated in the aboveProtein synthesis inhibitor article.
Note, by the way, that the Ribosomes of Prokaryotes (bacteria) and Eukaryotes (cells with nuclei) aren’t identical, and therefore the inhibitors/disruptors that work for one type of cell may not (and usually don’t) work on the other type. That’s why we can take antibiotics targeted at bacteria with little to no fear of them interfering with our eukaryotic cells’ functions.
(This is a simplified, somewhat hand-wavy response. There is a lot more to say, mainly because biological systems are anything but simple. Nevertheless this should be enough to get you started in the general direction.)
