4 public questions tagged with this topic.
Eosinophils help in fighting parasitic infections and play a role in allergic reactions.
Ref: NCERT Class 11 Biology Chapter 15: Body Fluids and Circulation Circulatory System - Comparative and Evolutionary Aspects
Sporozoans possess an infectious spore-like stage in their life cycle. Plasmodium, which causes malaria, is the example given for this protozoan group.
Ref: NCERT Class 11 Biology Chapter 2: Biological Classification Protista - Euglenoids Slime Moulds Protozoans
Parasitoids develop in or on a single host and normally require that host's death to complete their life cycle. Many parasitoid wasps lay eggs in caterpillars or other arthropods; larvae consume host tissues progressively, often delaying lethal damage until development is nearly complete. Typical parasites exploit a host for resources but generally gain from keeping it alive long enough for repeated feeding or transmission, so host death is not an obligatory endpoint. Parasitoids may be internal or external, and they certainly harm rather than coexist harmlessly with hosts. Their combination of intimate association and eventual lethality places them between conventional parasites and predators in consumer-resource classifications. This reasoning connects organismal behavior with broader ecological consequences. A mechanism that changes encounter rates, resource use, or reproductive success can scale up to alter population trajectories and the structure of species interactions. The alternatives can be separated by asking what changes for each participant and which process causes that change. That approach is more reliable than treating familiar examples as fixed labels, because many interactions shift with environmental context.
Ref: Ecology: From Individuals to Ecosystems, Begon et al., 5th Ed., Ch. 8-13
A forest can display an inverted or spindle-shaped pyramid of numbers because a small number of large trees support many herbivorous insects, birds, epiphytes, and parasites. Counting individuals ignores body size, so one massive producer may sustain thousands of much smaller consumers. Higher predator levels may again contain fewer individuals, creating a spindle profile rather than a simple monotonic inversion. This does not violate energetic constraints: producer biomass and production can still exceed the energy transferred to consumers. Higher trophic levels are often vulnerable because low energy supply produces small populations that are sensitive to habitat fragmentation and environmental variability. Ecological pyramids must be interpreted according to what is measured—individuals, standing dry mass, or energy flux—because these variables need not have the same shape. Standardizing by area and, for rates, by time is essential; otherwise ecosystems of different size, depth, or sampling duration cannot be compared meaningfully. Turnover explains many apparent paradoxes: a small, fast-renewing stock can support a larger consumer stock without reversing the direction of energy transfer.
Ref: Fundamentals of Ecology, Odum & Barrett, 5th Ed., Ch. 3
