Domain: Natural Science — Morphology
Target concept: Sexual dimorphism in red deer: Males possess branched antlers, whereas females are hornless.

Video generation prompt: Display a male and a female red deer standing side by side, and label their sexes. Observe the differences in head structure and body size between the two red deer.

Evaluation guide:
Target concept: Sexual dimorphism in Cervus elaphus is defined by the obligate, androgen-driven development of branched, deciduous antlers exclusively in males, a non-heritable, seasonally cyclical, energetically costly trait with zero expression in healthy adult females. Minimum mechanistic assumptions: (i) antlers are bony, not keratinous; (ii) pedicles are permanent bony bases only on males; (iii) hornlessness in females is absolute and invariant across ontogeny and geography. Phased storyline: [T=0–2s] Stable side-by-side setup: male (right) and female (left) stand motionless against neutral background, labels visible; [T=2–6s] Static observation window, viewer identifies: (a) male’s symmetrical branched antlers with ≥3 tines and pedicles, (b) female’s smooth, unadorned cranium, (c) male’s larger shoulder height confirmed by adjacent scale; [T=6–10s] Slow optical zoom to head region: antler branching and absence of any cranial outgrowth on female become unambiguous. Visibility constraints: frontal, eye-level view essential; no occlusion of antler tips, pedicles, or frontal bone; lighting must reveal surface texture (not just silhouette); labels must be legible without requiring inference.

Manual:
Red Deer (Cervus elaphus) Sexual Dimorphism Demonstration Instructions
I. Basic Demonstration Information
Demonstration Title: Red Deer (Cervus elaphus) Sexual Dimorphism (Male Branched Antlers vs. Female Hornless Head Structure) Demonstration
Subject: Natural Science – Morphology – Sexual Dimorphism
Demonstration Purpose: By displaying a healthy adult male and female red deer (Cervus elaphus) standing side by side in natural posture, this demonstration visually presents the core morphological sexual dimorphism — males possess large, branched, deciduous antlers; females are completely hornless — while also highlighting secondary differences in body size; it supports accurate visual recognition of sex-specific head structures and reinforces understanding of adaptive morphology in ungulates.

II. Demonstration Carrier/Equipment
Core Carrier: One adult male and one adult female red deer (Cervus elaphus), verified as conspecific, non-hybrid, and in full-grown, non-molt/non-shedding season (antlers fully calcified and velvet shed; no broken or abnormal antlers).
Auxiliary Equipment: Neutral gray matte background (to eliminate depth distortion and enhance contrast), front-facing static camera angle at eye level (1.5 m height), soft diffused daylight-equivalent lighting (no glare on antlers), waterproof sex labels (“MALE” and “FEMALE”) placed visibly below each animal’s chest (not obscuring head or shoulders), calibrated scale reference (1 m vertical ruler beside the rightmost animal) for relative size comparison.

III. Demonstration Content Description
Layout: Position male on the right, female on the left, 1.2–1.5 m apart on flat grassy substrate (natural ground texture visible), both standing upright, heads held naturally forward (not tilted up/down), facing directly toward camera. Maintain ≥3 m distance between animals and background to avoid occlusion.
State Control: Ensure animals are calm, alert, and motionless for ≥3 s during recording (no chewing, shaking, or walking); antlers must be fully exposed — no ear flicking, head turning, or vegetation blocking view.
Comparison Baseline: Select individuals of comparable age (adult, ≥3 years) and similar nutritional condition to minimize confounding variation; emphasize that *head structure* (presence/absence and branching of antlers) is the primary dimorphic trait; body size difference (male larger) is secondary but observable via side-by-side scaling.

IV. Observation of Core Phenomena
Female Head Structure Characteristics: The female on the left has a smooth, rounded cranial profile with no bony outgrowths, no pedicles visible, and no keratinous or osseous appendages whatsoever — completely hornless. Skin texture over frontal bone is uniform, unbroken, and uninterrupted.
Male Head Structure Characteristics: The male on the right displays a pair of large, symmetrical, multi-pointed (≥3 tines per antler), hardened bony antlers arising from prominent frontal pedicles. Antlers are branched (dichotomously or palmate), dark brown-gray in color, with visible annular ridges and smooth cortical surface — no velvet, no blood vessels, no shedding signs.
Body Size Comparison: Male stands visibly taller at shoulder (≥15% greater height) and broader in chest girth; both animals display typical red deer proportions (long legs, slender neck, rump higher than shoulders), confirming species identity.
Characteristic Stability: Antlers remain rigid and immobile; no antler wobbling, shedding, or collapse; no ambiguity in presence (male) vs. absence (female); labeling is legible and correctly assigned.

V. Summary of Key Knowledge Points and Principles
Core Concept Definition: Sexual dimorphism in morphology refers to consistent, heritable, sex-linked differences in anatomical structure — here, antler development is androgen-dependent and exclusive to males in Cervidae; females lack the hormonal trigger and genetic pathway for antlerogenesis.
Biological Significance:
— Reproductive Function: Antlers serve as weapons in male–male combat during rut and as visual signals of fitness to females.
— Energetic Trade-off: Antler growth is metabolically costly; absence in females reflects selective pressure to allocate energy to gestation/lactation instead.
— Taxonomic Reliability: Hornlessness in female red deer is 100% consistent across populations — a diagnostic, invariant trait distinguishing it from horned bovids (e.g., cattle, goats) where both sexes may bear horns.

VI. Demonstration Precautions
Species Verification: Confirm the animals are Cervus elaphus (red deer) and not moose (Alces alces) or wapiti; the common name “elk” is ambiguous across regions (it denotes the moose in British usage) and should not be used in place of “red deer”; use only wild-type or well-documented captive-bred stock — exclude antlered females (extremely rare pathological cases) or polled males (genetic anomalies).
Timing: Conduct during late summer–autumn (post-velvet, pre-shedding) to guarantee antler integrity and visibility.
Labeling & Framing: Labels must be orthographically aligned, non-reflective, and placed at same vertical position (mid-chest) for both animals; camera must capture full head-to-hock silhouette without cropping ears, antler tips, or hooves.
Duration: Video clip must last exactly 8–10 s: 2 s stabilization → 4 s static side-by-side view (core observation window) → 2 s slow zoom-in on heads (highlighting antler vs. hornless contrast).

Prompt Grounding rubric:
level_1: No red deer are present; or only one animal is shown; or both animals are mislabeled (e.g., a "MALE" tag placed on the hornless individual); or antlers are absent on both animals, or appear on the female instead of the male; or the background is inappropriate (e.g., dense forest interior, snowfield, barn interior) and obscures the animals; or no scale marker of any kind appears, making a size comparison impossible.
level_2: Two deer-like animals are present, but their proportions or antler shape look more like a moose's palmate rack than a red deer's branched antlers; the "MALE"/"FEMALE" labels are present but illegible, mispositioned, or overlapping the antlers; one animal is significantly cropped or blocked by the other; the male's antlers form a single unbranched spike rather than a branched rack; the female's head carries a bump, stub, or scar that could be mistaken for an antler base; the two animals show no noticeable size difference.
level_3: The male and female red deer are both correctly present and labeled; the male's antlers are branched and the female's head is bare, but the antlers look soft or fuzzy (still velvet-covered) rather than hardened bone; the female's head shows a minor skin mark (e.g., a small scar or insect bite) that could be confused for an antler remnant; a size difference between the two animals is visible but no ruler or comparable reference object appears anywhere in the frame; the labels are readable but tilted or low-contrast.
level_4: All core elements are correct: a male with multi-tined branched antlers, a female with a completely bare head, correct "MALE"/"FEMALE" labels, a plain uncluttered background, and a visible scale marker (e.g., a marked post or ruler) placed beside one of the animals; only minor flaws remain, such as a slight head tilt, a hoof cropped at the frame edge, antlers rendered a shade darker or lighter than natural brown-gray, or label text smaller than specified.
level_5: The scene matches the prompt precisely: an adult male and female red deer stand side by side on natural ground, facing the camera at eye level; the male shows symmetrical, multi-pointed branched antlers with at least three tines per side, rising from clearly visible pedicles; the female's head is completely smooth with no bony growth of any kind; "MALE" and "FEMALE" labels are centered at chest height, high-contrast, and do not obscure any anatomy; a scale marker (e.g., a one-meter post) stands fully visible beside one animal, and against it the male is clearly, noticeably taller at the shoulder than the female, by at least about 15%.

Scientific and Causal Correctness rubric:
level_1: Antlers appear on the female red deer, or are absent on the male; the antlers are drawn as a permanent keratin sheath that never sheds, like a bovid's horns, rather than as bone; the female shows small bony knobs or "mini-antlers" on her head; the male's antlers look bloody, actively shedding, or freshly broken; the link between sex and antler presence is broken entirely, e.g., antlers appear or vanish mid-scene with no biological basis.
level_2: Antlers correctly appear only on the male, but their form contradicts red deer biology: fused into a single unbranched mass, wildly asymmetrical between the two sides, or covered in an unnatural texture (e.g., looking metallic or plastic); the female's cranial silhouette shows an odd bulge or asymmetry suggestive of disease rather than ordinary hornlessness; the male and female appear the same overall size and build despite the expected male size advantage.
level_3: The sex-to-antler mapping is correct (antlers branched and bony on the male, the female's head bare), but the antlers show no visible pedicle (bony base), obscuring how they arise from the skull; a size difference between the animals is apparent in proportion (e.g., a broader chest or longer legs on the male) but nothing else in the scene reinforces that this reflects a biological, sex-linked pattern rather than coincidence.
level_4: Antler biology is correct throughout: branched, bony antlers arise from visible pedicles on the male only, and the female's head is unambiguously bare; the male's proportions (broader chest, taller shoulder, longer legs) plausibly reflect the size advantage typical of male red deer; only a minor weakness remains, such as the pedicles being present but not very prominent, or the antler surface lacking the fine ridged texture of real bone.
level_5: The full causal picture is visible: the male's antlers clearly rise from raised, bony pedicles on the frontal skull, showing their origin as an outgrowth of that structure, while the female shows zero pedicle or bony trace of any kind; the antlers branch in a natural, dichotomous pattern with at least three distinct tines per side and a cortical, bone-like surface texture rather than a smooth prop-like finish; the male's proportionally larger build (including a shoulder height at least about 15% greater than the female's, as confirmed against the visible scale marker beside the animals) is evident from body shape (broader chest, taller shoulder, longer legs), so the whole scene visually encodes that antlers are a male-only, hormonally driven trait in red deer.

Spatiotemporal Consistency rubric:
level_1: The two red deer appear to float above the ground with no visible leg-to-ground contact; the camera view is so distorted (e.g., an extreme wide-angle look) that one antler appears detached from the head; the shadows cast by the male and the female fall in different directions as if lit by separate light sources; the animals abruptly shift position or vanish between frames; the camera cuts or jumps erratically during the observation window.
level_2: Both red deer stand on the ground but with an unnatural stance (e.g., a hind leg bent at an odd angle, weight visibly unbalanced); a bright reflected highlight sits directly over the male's antlers, hiding their branching; the background shifts or blurs unevenly between the two sides of the frame; the zoom toward the heads happens so fast that the antlers and the female's bare crown are hard to make out; the "MALE"/"FEMALE" labels shift position or momentarily disappear during the shot.
level_3: Both red deer stand solidly on the same ground with a stable camera framing; the antler tips look slightly compressed or foreshortened from the chosen angle; lighting is generally even but one ear or antler falls into a deeper shadow than the rest of the scene; the labels stay in place but look slightly soft or blurred; the zoom toward the heads is smooth but only begins well after the animals have already been on screen, cutting into the initial static side-by-side view.
level_4: The scene stays spatially consistent: the male and female red deer stand on the same visible ground plane with a matching horizon line, and their shadows fall in the same direction and length; lighting stays even and soft, showing the antler surface detail without glare; the labels remain steady, sharp, and level; the zoom into the heads starts a couple of seconds in and finishes within a few seconds, moving smoothly with no jump cuts or warping of either animal's shape.
level_5: The whole sequence holds together as one continuous, physically coherent shot: perspective and framing stay constant except for the intended zoom; the male and female cast matching, correctly angled shadows consistent with a single light source throughout; the frontal view lets the viewer judge antler depth naturally, with the near ear partly overlapping the antler base rather than looking pasted on; the "MALE"/"FEMALE" labels keep the same size, position, and legibility from the first frame to the last; the zoom reads as a smooth optical push-in rather than a digital crop, and the motion throughout stays fluid with no visible stutters, freezes, or skips.