1.Relationships between organisms in nature.
Q 1. Forms of Biotic Relationships in Nature
Ans. - Symbiosis: Close and often long-term interactions
between different species.
- Mutualism: Both species benefit (e.g., clownfish and sea
anemone).
- Commensalism: One species benefits, the other is not
affected (e.g., remora fish and sharks).
- Parasitism: One species (parasite) benefits at the expense of
another species (host).
Q 2. Features of Parasitism
Ans.- Parasitism: A relationship where one organism (parasite)
lives on or in another organism (host), causing harm.
- Features:
- Dependence on host: Parasites rely on hosts for survival and
reproduction.
- Harm to host: Parasites can cause disease, nutrient
depletion, or other harm.
,Q 3. Classification of Parasitism
Ans. - Obligate parasitism: Parasites require a host to complete
their life cycle (e.g., Plasmodium spp. Causing malaria).
- Facultative parasitism: Parasites can live as parasites or free-
living organisms (e.g., some fungi).
- Temporary parasitism: Parasites only interact with hosts for a
short period (e.g., mosquitoes feeding on blood).
Q 4. Classification of Parasites
Ans. - Based on location:
- Ectoparasites: Live on the host’s surface (e.g., ticks, lice).
- Endoparasites: Live inside the host (e.g., tapeworms,
protozoa).
- Based on life cycle:
- Monogenetic parasites: Complete life cycle in one host (e.g.,
Ascaris lumbricoides).
- Digenetic parasites: Require two hosts to complete life cycle
(e.g., liver fluke).
- Polygenetic parasites: Require multiple hosts (e.g.,
Plasmodium spp.).
Q 5. Origin of Parasitism
,Ans.- Evolutionary adaptation: Parasitism likely evolved from
free-living ancestors that adapted to living on or in hosts.
- Host-parasite coevolution: Parasites and hosts evolve
together, with parasites developing mechanisms to evade host
defenses.
2. Medical and biological foundations of
parasitism.
Q 1. Parasitocenosis
Ans.- Parasitocenosis: The community of parasites living within
a single host organism.
- Importance: Understanding the interactions between different
parasites within a host can help in diagnosing and treating co-
infections.
Q 2. Relationships in the Parasite-Host System
Ans.- Complex interactions: The parasite-host relationship
involves complex interactions between the parasite's survival
strategies and the host's immune responses.
- Types of relationships:
, - Pathogenic effects: Parasites can cause direct damage to
host tissues or organs.
- Immunosuppression: Some parasites can suppress the
host's immune system, making it more susceptible to other
infections.
Q 3. Adaptations to the Parasitic Lifestyle
Ans.- Structural adaptations: Parasites often have specialized
structures for attachment and feeding (e.g., hooks, suckers).
- Biochemical adaptations: Parasites may produce enzymes or
molecules to evade the host's immune system or facilitate
nutrient uptake.
- Reproductive adaptations: Many parasites have high
reproductive rates to ensure transmission to new hosts.
Q 4. Development Cycles of Parasites
Ans. - Simple cycles: Some parasites have direct life cycles
involving a single host (e.g., Ascaris lumbricoides).
- Complex cycles: Many parasites have indirect life cycles
involving multiple hosts (e.g., Plasmodium spp. transmitted by
mosquitoes).
- Importance: Understanding the life cycle is crucial for
developing strategies to prevent and control parasitic infections.