Download App

Organisms and Populations — BIOLOGY STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceBIOLOGYOrganisms and Populations5 Marks
Question
Discuss the various types of positive interactions between species.
✓

Answer

Following are the positive interactions between species:
  1. Mutualism: This is a relationship between two organisms in which both the organisms are benefitted. Lichen is a very good example of mutualism. Lichen is an association of fungi and algae. The fungal part attaches to the substratum and gets water and minerals for the algal part. The algal part carries out photosynthesis and provides food to the fungal part.
  2. Commensalism: This is a relationship between two organisms in which one organism is benefitted, while another organism is neither at gain nor at loss. Egrets keep on sitting on the back of herbivore animals; like buffalo, cow, etc. when the cattle forage for grass, the insects under the grass fly away haphazardly. This gives a chance to the egrets to feed on insects.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "5 Marks Questions" from Organisms and Populations→Organisms and Populations — all question types→BIOLOGY STD 12 Science question papers→Gujarat Board STD 12 Science question papers→Gujarat Board question paper generator→

Similar questions

Explain spermatogenesis.
→
Match the items in Column I with those in Column II.
S.No.
Column I
S.No.
Column II
(A)
Pyramid of energy
(i)
Phytoplanktons
(B)
Pyramid of biomass
(ii)
Mesic forest
(C)
Climax community
(iii)
Upright/ inverted
(D)
Hydrarch succession
(iv)
Alwayes upright
 
 
(v)
Pioneer species
→
Describe the different methods for treatment of cancer.
→
During the course of evolution why DNA was chosen over RNA as genetic material? Give reasons by first discussing the desired criteria in a molecule that can act as genetic material and in the light of biochemical differences between DNA and RNA.
→
Describe the mechanism of inheritance of the ABO system of blood group, highlighting the principle of genetics involved in it.

OR

Explain the genetic basis of blood grouping in human population.

→
  1. Taking an example of a small pond, explain how the four components of an ecosystem function as a unit.
  2. Name the type of food chain that exists in a pond.
→
An organism is able to survive on a culture medium, containing nutrient A, by the enzyme-catalysed reactions.
$\text{A}\xrightarrow{\ \ \ \text{p}\ \ \ }\text{B}\xrightarrow{\ \ \ \text{q}\ \ \ }\text{C}\xrightarrow{\ \ \ \text{r}\ \ \ }\text{D}$
A mutant organism failed to survive on this medium, but grew well when nutrient B was added to it.
  1. Which gene of this mutant organism is defective?
  2. What does such a condition indicate of ?
  3. Mention the major components and their functions in an operon.
  4. Indicate the value expressed in this sequence of reactions.
→
Answer the following questions:
You are given tall pea plants with yellow seeds whose genotypes are unknown. How would you find the genotype of these plants? Explain with the help of cross.
→
  1. Cancer is one of the most dreaded disease. Explain 'contact inhibition' and 'metastasis with respect to the disease.
  2. Name the group of genes that have been identified in normal cells that could lead to cancer. How do these genes cause cancer?
  3. Name any two techniques that are useful in detecting cancers of internal organs.
  4. Why are cancer patients often given a-interferon as part of the treatment?
→
In which categories have been classified the contraceptive methods. Describe any three methods in detail.
→