In biology, the concept of 'phenotypic plasticity' refers to the ability of a single genotype to produce different phenotypes in response to different environmental conditions. This means that an organism's physical or behavioral traits can vary depending on factors like temperature, food availability, or light, even if its genetic code remains unchanged. Phenotypic plasticity allows organisms to adapt to changing environments without genetic evolution, often within a single generation. It is a key mechanism for survival in dynamic habitats.
🎧 듣기 강의
Professor: Let me give you a concrete example from a study on water fleas. Water fleas are tiny crustaceans that live in ponds. When predators like fish are present in the water, the water fleas detect chemical cues released by the fish. In response, they develop a protective helmet and spikes on their heads. These structures make them harder for fish to swallow. However, when no predators are present, the same water fleas grow smooth, rounded heads. This change is not genetic—they have the same DNA. It’s purely driven by the environment. So, in just a few days, the water fleas alter their physical appearance to match the threat level. This is a classic case of phenotypic plasticity.
❓ 문제 Using the example from the lecture, explain the concept of phenotypic plasticity.
📊 TOEFL 말하기 평가 기준
Delivery: Fluency, pronunciation, intonation
Language Use: Grammar, vocabulary, sentence variety
Topic Development: Accurately explain the reading concept and restate the lecture examples
Scored 0-30 based on holistic scoring (original 0-4, scaled to 30). 30s preparation, 60s response.
💡 답변 팁
Note the core concept definition from the reading (usually 1-2 sentences)
Record 1-2 specific examples the professor uses in the lecture
Start with the concept definition, then explain with lecture examples
Use template phrases: "The reading defines... The professor illustrates this by..."
Keep within 60s; ensure clarity and fluency
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