Domain: Natural Science — Morphology
Target concept: Sexual dimorphism in the ostrich: Males have black and white feathers, females have grayish-brown feathers.

Video generation prompt: An observer compares an adult male and female ostrich; the left is an African female ostrich, and the right is an African male ostrich.

Evaluation guide:
(i) Target concept: Visual identification of sexually dimorphic plumage in African ostriches via side-by-side comparison.
Minimum mechanism: Ostriches must be biologically mature adults; plumage coloration must be genetically typical (not albino, melanistic, or juvenile); ambient lighting must permit accurate color discrimination without metamerism or spectral distortion.
(ii)Storyline: Frame opens with static, centered, frontal view of two adult ostriches aligned horizontally. Left ostrich enters/viewer perceives first as grayish-brown; right ostrich enters/viewer perceives second as black-and-white. No motion distracts from comparative observation. Viewpoint remains fixed; lighting remains stable; no occlusion occurs. Color contrast is immediately legible under natural daylight-equivalent illumination with no post-processing color shift.

Manual:
Experimental Procedure
1. Place an adult African female ostrich on the left side and an adult African male ostrich on the right side in a neutral outdoor setting.
2. Ensure both ostriches are fully visible, stationary, and facing forward in the same frame.
Observation of Experimental Phenomena
The left ostrich displays uniform grayish-brown plumage across neck, back, and wings; the right ostrich displays sharply contrasting black feathers on body and wings with clean white feathers on wings and tail.
Summary of Experimental Principles
Sexual dimorphism in the ostrich: Males have black and white feathers, females have grayish-brown feathers.

Prompt Grounding rubric:
level_1: No ostriches present; or only one ostrich visible; or ostriches not simultaneously visible in same frame; or no clear left-right spatial labeling implied by composition
level_2: Two ostriches visible, but spatial arrangement ambiguous (e.g., overlapping, rotated, or diagonally offset such that left/right assignment is unverifiable); or at least one ostrich is partially occluded, cropped, or out-of-frame
level_3: Two adult ostriches fully visible and simultaneously present in same frame, with unambiguous side-by-side spatial arrangement (left ostrich and right ostrich clearly discernible by fixed frontal viewpoint and horizontal alignment)
level_4: All conditions of score 3 satisfied, AND both ostriches are stationary or exhibit natural low-motion posture (no walking, running, or turning away), AND camera viewpoint remains fixed and frontal throughout, AND no visual artifacts distort spatial labeling (e.g., mirror reversal, perspective skew, or forced asymmetry)
level_5: All conditions of score 4 satisfied, AND left ostrich is positioned strictly on the viewer’s left half of the frame with full body centered horizontally within that half, AND right ostrich is positioned strictly on the viewer’s right half of the frame with full body centered horizontally within that half, AND no compositional ambiguity exists: left/right assignment is instantly and unambiguously decidable by human observer without inference

Scientific and Causal Correctness rubric:
level_1: Both ostriches display identical plumage color (e.g., both black-and-white or both grayish-brown); or colors are non-biological (e.g., blue, green, pink, patterned); or coloration is indeterminate due to extreme lighting, blur, or monochrome rendering
level_2: At least one ostrich displays biologically incorrect coloration (e.g., male with grayish-brown feathers OR female with black-and-white feathers); or both ostriches show intermediate/mixed/gradient plumage inconsistent with sexual dimorphism; or coloration is obscured by non-occlusive but visually dominant elements (e.g., heavy shadow, glare, uniform fog)
level_3: Left ostrich displays grayish-brown plumage AND right ostrich displays black-and-white plumage; OR left ostrich displays black-and-white plumage AND right ostrich displays grayish-brown plumage; i.e., color contrast is present but spatial assignment (female-left/male-right) is reversed
level_4: Left ostrich displays grayish-brown plumage AND right ostrich displays black-and-white plumage (matching posted_prompt assignment) AND both color patterns are complete across visible body regions (neck, back, wings, tail); AND no local color contamination (e.g., black patches on female, brown streaks on male) appears on primary feathered areas
level_5: All conditions of score 4 satisfied, AND plumage coloration is consistent across all visible anatomical regions (including head, neck, torso, upper thighs) with no region-specific deviation; AND no color bleeding, chromatic aberration, or lighting-induced hue shift alters perceived feather color; AND color distinction is sharp and categorical, with no perceptual ambiguity between grayish-brown and black-and-white

Spatiotemporal Consistency rubric:
level_1: Ostriches appear to teleport (discontinuous position change between frames); or one ostrich vanishes/reappears mid-video; or severe structural warping (e.g., bent legs, fused bodies, floating limbs); or abrupt light/shadow discontinuity (e.g., sudden cast shadow appearance/disappearance without cause)
level_2: Mild spatial distortion: e.g., inconsistent scale between ostriches (one visibly larger/smaller despite same distance), or transient clipping of limbs/body parts across frames without motion justification, or flickering occlusion (e.g., leg alternately visible/invisible without movement), or unstable horizon line or frame tilt
level_3: Both ostriches maintain consistent relative size and proportional anatomy across all frames; no limb disconnection, morphing, or fusion; lighting and shadow remain globally coherent (same direction, softness, intensity); no object flicker or frame dropout
level_4: All conditions of score 3 satisfied, AND ostriches maintain fixed positions relative to each other and to frame edges (no lateral drift, zoom, pan, or rotation); AND motion (if any) is biomechanically plausible (e.g., subtle head bob, slow blink, gentle breathing) and synchronous or independent but never contradictory (e.g., no simultaneous forward lunge and backward lean)
level_5: All conditions of score 4 satisfied, AND inter-frame motion is smooth and continuous (no strobing, judder, or frame duplication); AND depth cues are consistent (e.g., no foreground ostrich casting shadow on background ostrich when both are on same plane); AND no temporal artifact (e.g., ghosting, motion blur violating natural kinetics, or inconsistent frame pacing)