EBK LIFE: THE SCIENCE OF BIOLOGY
EBK LIFE: THE SCIENCE OF BIOLOGY
11th Edition
ISBN: 8220103935432
Author: Sadava
Publisher: MAC HIGHER
bartleby

Concept explainers

bartleby

Videos

Question
Book Icon
Chapter 30, Problem 1Q
Summary Introduction

To review:

The represented data are given in the graph and the purpose of reverse development in some cnidarians.

Introduction:

Cnidarians are marine, invertebrate, and radially symmetrical animals that belong to phylum Cnidaria. These animals do not have a complete gut instead have a blind sac called the gastrovascular cavity, which is connected to the single opening called the mouth. The cnidarians exhibit two distinct stages during its life cycle.

Expert Solution & Answer
Check Mark

Explanation of Solution

The life cycle of all cnidarians involves the formation of two distinct body forms: one sessile (immobile) and other motile. The sessile stage is known as the polyp, which is cylindrical in structure and is attached to a substratum, while the motile stage is known as the medusa, which is umbrella or bell shaped and is free swimming in the sea. The polyp stage exhibits the asexual young stage that converts into the medusa stage representing the sexual mature phase of the organism.

Some cnidarians such as Turritopsis dohrnii shows the reversal of sexual mature phase into young asexual phase. This reversal process is referred to as the reduction. The medusa stage under reduction into its younger version is called as the reducing medusa. Such cnidarians are regarded as “immortal jellies.” Research has shown that this revert back process occurs when the organism faces stress conditions in its surrounding such as unavailability of food, injury, and unfavorable conditions to sexually reproduce.

The following graph represents the data generated when the Turritopsis dohrnii species were incubated under different concentrations of cesium chloride (CsCl) for 3 hours, as a part of a study of reversion phenomenon shown by this species.

EBK LIFE: THE SCIENCE OF BIOLOGY, Chapter 30, Problem 1Q

From the graph, it is clear that at CsCl concentration of 14.5 mM (low), maximum number of reducing medusa stages were recovered as compared to the control where no stress is given and maximum number of normal medusa stages were seen. At intermediate CsCl concentrations (29 Mm and 58 mM), equal number of reducing medusa stages and polyp stages were seen. However, at very high CsCl concentration (116 mM), absence of reducing medusa was seen while maximum number of polyp stages were recovered. This represents the reversion of all the medusa stages into the polyp stage.

Conclusion

Therefore, it can be concluded that as the stress conditions increase in the environment of cnidaria, the revert back phenomenon is more as more number of medusa stages starts reverting back to the young polyp stages. This reversion process contributes to the immortality of these animals.

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
1. In vivo testing provides valuable insight into a drug’s kinetics. Assessing drug kinetics following multiple different routes of administration provides greater insight than just a single route of administration alone. The following data was collected in 250 g rats following bolus iv, oral (po), and intraperitoneal (ip) administration.Using this data and set of graphs, determine: (a) k, C0, V, and AUC* for the bolus iv data  (b) k, ka, B1, and AUC* for the po data  (c) k, ka, B1, and AUC* for the ip data  (d) relative bioavailability for po vs ip, Fpo/Fip  (e) absolute po bioavailability, (f)Fpo absolute ip bioavailability, Fip    MAKE SURE ANSWERS HAVE UNITS if appropriate. SHOW ALL WORK, including equation used, variables used and each step to your solution.
2. Drug quantification from plasma is commonly performed by using techniques such as HPLC or LC/MS. However, these methods do have limitations, and investigators may choose to use a radiolabeled analog of a drug instead. Radioligands are molecules that contain radioactive isotopes, commonly 3H or 14C. This technique allows investigators to quantify drug concentration from radiation measurements. The following measurements were made in 250 g rats following oral administration of 18.2 µCi of a 14C-labeled drug of interest: Time (min) Plasma Radiation Levels (µCi/L) 0 0.0 2 9.7 4 19.2 7 25.3 9 37.8 12 39.6 14 45.8 17 48.8 20 52.0 25 56.4 30 59.2 35 60.1 40 61.1 45 62.1 50 62.8 60 63.1 70 62.1 80 60.1 90 57.3 100 55.5 110 53.7 120 52.2 150 48.0 180 45.0 240 39.0  Note that a µCi is a measure of the amount of radioactivity and hence is a measure of the amount of drug present.  Given that the oral bioavailability of this drug is known to be essentially 100%, estimate the following from this…
The current nutrition labelling regulation in Hong Kong requires food manufacturer to list E+7 information on the package of pre-packaged food products. Do you think that more nutrients, such as calcium and cholesterol, shall be included?
Knowledge Booster
Background pattern image
Biology
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.
Similar questions
SEE MORE QUESTIONS
Recommended textbooks for you
Text book image
Biology 2e
Biology
ISBN:9781947172517
Author:Matthew Douglas, Jung Choi, Mary Ann Clark
Publisher:OpenStax
Text book image
Concepts of Biology
Biology
ISBN:9781938168116
Author:Samantha Fowler, Rebecca Roush, James Wise
Publisher:OpenStax College
Text book image
BIOLOGY:CONCEPTS+APPL.(LOOSELEAF)
Biology
ISBN:9781305967359
Author:STARR
Publisher:CENGAGE L
Text book image
Biology (MindTap Course List)
Biology
ISBN:9781337392938
Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. Berg
Publisher:Cengage Learning
Text book image
Biology: The Dynamic Science (MindTap Course List)
Biology
ISBN:9781305389892
Author:Peter J. Russell, Paul E. Hertz, Beverly McMillan
Publisher:Cengage Learning
Text book image
Aquaculture Science
Biology
ISBN:9781133558347
Author:Parker
Publisher:Cengage
Phylogeny and the Tree of Life; Author: Professor Dave Explains;https://www.youtube.com/watch?v=KLMn4XwS8Tw;License: Standard YouTube License, CC-BY