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#species diversity

23 public questions tagged with this topic.

Basic Evolution

Adaptive radiation is best described as:

Adaptive radiation describes rapid diversification of single ancestor into many forms exploiting different ecological niches, driven by ecological opportunity, such as Darwin's finches evolving varied beaks for seeds, insects and cactus, or cichlids in African lakes. It involves divergent evolution, morphological innovation and often occurs after colonization or mass extinction. Homologous structures reflect common ancestry. Classic example illustrates Diversification from a common ancestor as diversification from common ancestor into distinct niches. This concept integrates genetics, ecology and molecular evidence, frequently tested in NEET, GATE and CSIR-NET, highlighting links between genotype, phenotype and environment.

Ref: Futuyma, Evolution, Variation, Drift, and Speciation Concepts.

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Theory of evolution

Adaptive radiation results from

Adaptive radiation describes rapid diversification of single ancestor into many forms exploiting different ecological niches, driven by ecological opportunity, such as Darwin's finches evolving varied beaks for seeds, insects and cactus, or cichlids in African lakes. It involves divergent evolution, morphological innovation and often occurs after colonization or mass extinction. Homologous structures reflect common ancestry. Classic example illustrates Different niches from common ancestor as diversification from common ancestor into distinct niches. This concept integrates genetics, ecology and molecular evidence, frequently tested in NEET, GATE and CSIR-NET, highlighting links between genotype, phenotype and environment.

Ref: Campbell Biology, 12th ed., Chapter 22: Descent with Modification.

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Biogeography Complete

According to the theory, species diversity is balanced between:

“Immigration and extinction” for according to the theory, species diversity is balanced between. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Island biogeography explains species richness as a dynamic balance between immigration and extinction. Immigration generally declines as an island fills with species, whereas extinction rises as more species divide finite area and maintain smaller populations. The remaining alternatives—“Competition and predation”, “Mutation and drift”, “Abiotic and biotic factors”—refer to different states, processes, or scales and therefore do not express the same causal relationship. Larger islands usually support more habitats and larger populations, lowering extinction risk; less isolated islands receive colonists more readily and may experience rescue effects. These mechanisms also apply to habitat fragments that function as ecological islands. This distinction matters because similar surface patterns can arise through different mechanisms, whereas ecological prediction depends on identifying the mechanism that actually changes rates.

Ref: Biogeography, Lomolino et al., 5th Ed., Ch. 5-8

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Biogeography

According to the theory, species diversity on islands is:

“Dynamic and balanced” for according to the theory, species diversity on islands is. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Island biogeography explains species richness as a dynamic balance between immigration and extinction. Immigration generally declines as an island fills with species, whereas extinction rises as more species divide finite area and maintain smaller populations. The remaining alternatives—“Fixed and constant”, “Decreasing continually”, “Increasing continually”—refer to different states, processes, or scales and therefore do not express the same causal relationship. Larger islands usually support more habitats and larger populations, lowering extinction risk; less isolated islands receive colonists more readily and may experience rescue effects. These mechanisms also apply to habitat fragments that function as ecological islands. Field observations could test this account by measuring the proposed driver and the demographic or ecosystem response while controlling plausible confounding factors.

Ref: Biogeography, Lomolino et al., 5th Ed., Ch. 1-4

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