1. Which factor of an ecosystem includes
plants, animals and microorganisms?
a. Biotic factor b. Abiotic factor
c. Direct factor d. Indirect factor
2. An assembladge of individuals of
different species living in the same habitat
and having functional interactions is
................
a. Biotic community
b. Ecological niche
c. Population
d. Ecosystem
3. Association between sea anemone and
Hermit crab in gastropod shell is that of
................
a. Mutualism b. Commensalism
c. Parasitism d. Amensalism
4. Select the statement which explains best
parasitism.
a. One species is benefited.
b. Both the species are benefited.
c. One species is benefited, other is not
affected.
d. One species is benefited, other is
harmed.
5. Growth of bacteria in a newlly
innoculated agar plate shows ................
a. exponential growth
b. logistic growth
c. Verhulst-Pearl logistic growth
d. zero growth
Answers
Answer:
1. Biotic
2.Ecosystem
3.Mutualism
4. One species in benefited
5.exponential growth
Answer:
1. a) Plants, animals, and microorganisms belong to the biotic factor of an ecosystem.
Explanation
The term biotic refers to the living or once-living components of a community. Thus, living organisms such as plants, animals, and microorganisms belong to biotic factors of the ecosystem.
2. a) An assemblage of individuals of different species living in the same habitat and having functional interactions is the Biotic community.
Explanation
Biotic community is a community wherein organisms belonging to different species are functionally interacting and are living in the same habitat. It is also known as biocoenosis. Living things, such as animals, plants, and microbes, are referred to as biotic components, while nonliving components, such as water, air, etc are referred to as abiotic components. Both biotic and abiotic populations make up an ecosystem.
3. b) Association between sea anemone and Hermit crab in gastropod shells is that of Commensalism.
Explanation
The symbiotic association, in which the sea anemone and the Hermit crab participate is called commensalism. It's a form of symbiotic interaction in which one creature benefits while the other suffers no damage. Many creatures in shallow benthic marine habitats rely on empty gastropod shells as a source of food. Hermit crabs find shelter in shells and are so protected from predators. In exchange, the sea anemones get to eat anything the hermit crab leaves behind.
4. d) In parasitism one species is benefited, and the other is harmed.
Explanation
The term "parasitism" refers to a relationship between two living species in which one organism benefits at the expense of the other. The parasite is the creature that benefits, while the host is the organism that is hurt.
5. a) Growth of bacteria in a newly inoculated agar plate shows exponential growth.
Explanation
When bacteria are placed in a nutrient-rich medium, Agar, in this case, they go through four stages of development that are typical of a bacterial growth curve. Bacteria do not proliferate quickly after being inoculated into a fresh medium, and the population number remains constant. The cells are metabolically active and only grow in size during this time, known as the lag phase. During this period they synthesize enzymes and substances required for cell division and population expansion. The bacteria subsequently enter the log or exponential phase, in which the number of cells grows in a logarithmic manner. This phase continues until bacteria are deprived of all the nutrients resulting in a stationary phase following which the cell growth stops and ultimately leads to the death phase.