Domain: Natural Science — Morphology
Target concept: Sexual Reversal in the African Wrasse: Female coloration is pale before sexual reversal, and male coloration becomes vibrant after reversal.

Video generation prompt: The screen shows a reef aquarium in which a dominant female African wrasse is undergoing sex reversal.

Evaluation guide:
(i) Target concept: Sequential, localized, and anatomically constrained pigment pattern emergence during protogynous sex reversal in labrid fishes.
Minimum mechanism: Functional dominance hierarchy triggers neuroendocrine cascade (e.g., cortisol/testosterone shift) inducing melanophore/xanthophore proliferation in specific dermal zones, not generalized melanin upregulation or pigment cell migration across entire epidermis.
(ii)Storyline: [Frame 0–2s] Dominant female wrasse swims steadily in reef aquarium, exhibiting uniform pale pink-beige body coloration with no male-typical markings; [Frame 3–6s] First discrete blue hue appears on forehead/nape region while body remains pale; concurrently, faint yellow-orange intensifies along dorsal fin base and caudal peduncle; [Frame 7–10s] Blue and yellow-orange patches increase in saturation and definition but remain confined to native male-pattern zones; pale baseline persists unchanged across flank, abdomen, and ventral surfaces; camera maintains fixed medium-close framing with full fish visibility and stable reef background.

Manual:
Experimental Procedure
1. Place a single dominant female African wrasse into a mature reef aquarium with live coral, sandy substrate, and ambient reef lighting.
2. Observe continuously for 10 seconds as sexual reversal initiates.
Observation of Experimental Phenomena
A pale-colored female wrasse is visible at video start; during the 10-second interval, localized vibrant color patches (blue on head, yellow-orange on caudal peduncle and dorsal base) emerge progressively while the rest of the body retains pale female coloration.
Summary of Experimental Principles
In African wrasses, sex reversal is sequential and irreversible: dominant females undergo morphological transformation into males, marked first by localized development of male-specific chromatophore patterns on anatomically defined regions, not whole-body color shift.

Prompt Grounding rubric:
level_1: No reef aquarium setting appears, no wrasse-like fish is present, or the scene has nothing to do with an aquarium fish (e.g., a different animal, an empty tank, or an unrelated background).
level_2: A reef aquarium appears but no wrasse is in it, or a fish is present but its body shape and coloring don't resemble a wrasse (e.g., a round, deep-bodied reef fish rather than the wrasse's elongated shape), or the tank looks like a bare or freshwater setup rather than a coral reef.
level_3: A reef aquarium with live coral or rockwork is shown, and one wrasse-shaped fish (elongated body, continuous dorsal fin, pointed snout) stays visible in the shot, but its coloring never changes and nothing hints at a female-to-male transition.
level_4: Additionally, the fish clearly starts out with a uniform, muted pale coloring (no bright blue or yellow markings anywhere on it) and stays the single, centered subject of the shot, with the reef setting fully visible around it and no other fish or object competing for attention.
level_5: Additionally, later in the clip the same fish is shown carrying at least one patch of brighter, non-pale coloring somewhere on its body in addition to the pale coloring it started with (the video visibly shows the fish partway through a change in appearance rather than only ever displaying one unchanging color state), with the fish fully visible and unobstructed throughout.

Scientific and Causal Correctness rubric:
level_1: The fish's coloring never changes across the video, it shows a fixed but wrong coloring (e.g., solid black, grey, or brown throughout), or the color pattern shown has nothing to do with wrasse biology (e.g., stripes or an iridescent sheen typical of unrelated fish).
level_2: A color change happens, but it runs backward (a brightly colored fish fades toward pale instead of a pale fish gaining color), the new coloring appears instantly as a fully saturated pattern with no pale starting stage ever shown, or the fish already shows bright male-type coloring in the very first frame.
level_3: The fish is pale at the start and gains color as the clip proceeds, but the new color spreads evenly over the whole body (e.g., uniform darkening or overall brightening) rather than showing up as separate patches on specific areas such as the head or the base of the tail.
level_4: Additionally, the new coloring stays confined to zones consistent with a wrasse's known male pattern (for example a distinct blue patch on the head, or a yellow-orange patch near the base of the tail), while the rest of the body (flanks, belly) is still visibly pale at the same time, rather than the whole fish changing together.
level_5: Additionally, by the end of the clip the pale coloring is still visible over most of the body while the blue head patch and/or yellow-orange tail-base patch look more distinct and saturated than where they started, no unrelated colors (red, purple, green) ever appear, and the fish never jumps to full, even, all-over saturation.

Spatiotemporal Consistency rubric:
level_1: The fish disappears and reappears at a different spot, the tank's coral or glass structure changes or vanishes between frames, the lighting suddenly switches (e.g., bright reef light to near-darkness) within a second or two, or part of the fish's body disappears and comes back.
level_2: The fish's facing direction flips abruptly with no visible turn, a coral piece or rock in front of the fish appears and disappears between frames, the background flickers or warps noticeably, or a hard-edged glare shows up on the fish's body that doesn't match the tank's otherwise soft, diffuse lighting.
level_3: The fish only drifts slightly without any sudden jump in position, any brief blur of its outline clears up quickly, and the coral and substrate around it keep the same relative place and shape throughout.
level_4: Additionally, the fish keeps a consistent spot relative to the tank walls, substrate, and nearby coral while it swims, any turns happen as a smooth rotation rather than a snap-cut, the light appears to fall from the same overhead source at a steady brightness for the whole clip, and no part of the fish or tank stretches or warps unnaturally.
level_5: Additionally, the fish's body moves with a natural side-to-side swimming undulation rather than gliding rigidly, near and far objects (foreground coral, the fish, background rockwork) shift believably relative to one another as the fish moves, the water surface and any reflections stay visually calm rather than glitching, and the swim's overall pace never suddenly speeds up or freezes.