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Zorluk: OrtaEvidence for Evolution: Comparative Biochemistry and Biogeography

Comparative serological tests demonstrate that the blood serum proteins of the South American llama (Lama glamaLama\ glama) exhibit a very high degree of immunological cross-reactivity with anti-serum raised against the Old World camel (Camelus dromedariusCamelus\ dromedarius). Which of the following statements best explains this biochemical and biogeographical observation?

  1. Llamas and Old World camels shared a relatively recent common ancestor before ancestral populations were geographically isolated by vicariance.Cevap
  2. B
    Llamas independently developed serum proteins identical to Old World camels as an acquired physiological response to arid high-altitude environments.
  3. C
    The structural similarity in serum proteins represents an analogous feature resulting from convergent evolution rather than common ancestry.
  4. D
    The precipitation reaction observed in serological tests demonstrates discontinuous genetic variation within a single generation.

Cevap

Llamas and Old World camels shared a relatively recent common ancestor before ancestral populations were geographically isolated by vicariance.
High serological cross-reactivity indicates close similarity in blood protein sequences, which directly reflects a shared genetic code derived from a recent common ancestor. Combined with biogeographical evidence, this confirms that ancestral camelids inhabited connected landmasses before geographic isolation led to speciation into modern llamas and camels.

Adım Adım Çözüm

1
Analyze the biochemical evidence
High immunological precipitation between serum proteins of llamas and camels indicates strong primary protein structure similarity.
Proteins reflect gene sequences; higher cross-reactivity signifies greater genetic similarity.
2
Integrate biogeographical context
Llamas (South America) and camels (Asia/Africa) are geographically separated today across continents.
Geographic separation of closely related taxa points to past continental drift or migration followed by isolation (vicariance).
3
Synthesize the evolutionary conclusion
The biochemical affinity confirms common ancestry, while their current distribution illustrates evolutionary divergence after geographic isolation.
Comparative biochemistry and biogeography combined provide robust evidence for common descent and divergence.

Anahtar Kavram

Biochemical Homology and Biogeographical Vicariance
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