Three basic adaptive responses—regulatory, acclimatory, and developmental—may occur in organisms as they react to changing environmental conditions.
Topic
How organisms—specifically water bugs—adapt to environmental changes, with a focus on reversible and irreversible responses.
Framework
Theme / Example
Main Point
Organisms can adapt to environmental changes through regulatory, acclimatory, and developmental responses; in water bugs, the developmental response determining wing type is an environmentally driven, permanent adjustment rather than a genetic one. *The Most Valuable Sentence appears in the third paragraph: *
P1: Types of Adaptive Responses
This paragraph introduces the three major types of adaptive responses: regulatory (quick, reversible physiological adjustments), acclimatory (slower, reversible structural changes), and developmental (usually permanent, fixed during development).
P2: Developmental Responses in Water Bugs
Here, the passage zooms in on developmental responses—using water bugs as an example—to explain how different generations have different wing types based on their seasonal needs. The summer generation shows two forms (some with normal wings, some with reduced wings), while the overwintering generation always has full wings for dispersing. This dimorphism is a strategy for survival given environmental uncertainties.
P3: Environmental Determination of Wing Type
This paragraph explains that the wing type variation in water bugs is not genetic, but determined by the temperature during egg development—cold temperatures lead to reduced wings, while warm temperatures lead to full wings. All overwintering bugs come from eggs formed in warm temps, ensuring full wings for migration; experimental evidence supports that temperature, not genetics, decides wing form.