check your understanding
in what two ways can hair evidence classified?

how can hair be useful to investigators if the follicle is not present?

what information can hair give investigators?

highlight the origins of hair on the human body.

what protein composes strand of hair?

what are some ways that hair can be destroyed?

Question

check your understanding
in what two ways can hair evidence classified?

how can hair be useful to investigators if the follicle is not present?

what information can hair give investigators?

highlight the origins of hair on the human body.

what protein composes strand of hair?

what are some ways that hair can be destroyed?

Accepted Answer

### 1. In what two ways can hair evidence be classified?
# Brief Explanations:
Hair evidence can be classified as either **human hair** or **animal hair**. Another way is by its **stage of growth** (anagen, catagen, telogen) or by its **morphological characteristics** (e.g., color, texture, structure like cuticle, cortex, medulla patterns). The two primary classification ways often focus on origin (human/animal) and growth stage or morphological traits.
# Answer:
Hair evidence can be classified in two ways: 1. By origin (human hair or animal hair); 2. By growth stage (anagen, catagen, telogen) or morphological characteristics (e.g., cuticle, cortex, medulla patterns, color, texture).

### 2. How can hair be useful to investigators if the follicle is not present?
# Brief Explanations:
Even without the follicle (which contains DNA), hair still has value. Its **morphological features** (cuticle scale pattern, cortex pigment distribution, medulla type) can link it to a species (e.g., human vs. animal) or narrow down to a group (e.g., hair texture, color matching a suspect). Chemical analysis of the hair shaft (e.g., drug residues, heavy metals) can reveal past exposures or drug use, aiding in investigations.
# Answer:
Without a follicle, hair is useful via: 1. Morphological analysis (cuticle, cortex, medulla traits) to identify species, hair type (e.g., head, body), or match to a source; 2. Chemical analysis (e.g., drug residues, toxins) to detect substance use or environmental exposures.

### 3. What information can hair give investigators?
# Brief Explanations:
Hair provides multiple insights:
- **Biological origin**: Human vs. animal, or hair type (e.g., head, pubic, facial).
- **Physical traits**: Color, texture, length (suggesting grooming habits or ethnicity clues).
- **Forensic clues**: Presence of drugs/toxins (via chemical analysis), trauma (e.g., cut marks from scissors), or linkage (morphology matching a crime scene to a suspect). If the follicle is present, DNA can identify an individual; without it, morphological/chemical data still helps.
- **Environmental info**: Exposure to chemicals (e.g., pesticides, pollutants) or dietary clues (via stable isotope analysis).
# Answer:
Hair gives investigators:
- Origin (human/animal, hair type like head/pubic).
- Physical traits (color, texture, length).
- Chemical info (drug residues, toxins, environmental exposures).
- Linkage clues (morphology matching a suspect/scene) or trauma (e.g., cut marks).
- (With follicle) DNA for individual identification.

### 4. Highlight the origins of hair on the human body.
# Brief Explanations:
Human hair originates from **hair follicles** embedded in the dermis layer of the skin. Follicles are distributed across the body, with different densities and hair types:
- **Head**: Scalp hair (varied textures, colors, growth cycles).
- **Face**: Beard, mustache (in males), or vellus hair (fine, non - pigmented).
- **Body**: Trunk, limbs (vellus or terminal hair, e.g., underarm, pubic).
- **Pubic region**: Coarse, curly terminal hair.
- **Eyelashes/eyebrows**: Protect eyes, with short, thick growth.
Follicles generate hair via the hair growth cycle (anagen, catagen, telogen), and hair type (terminal/vellus) varies by body region.
# Answer:
Human hair originates from **hair follicles** in the skin’s dermis, distributed across:
- Scalp (head hair).
- Face (beard, mustache, vellus hair).
- Body (trunk, limbs: vellus or terminal hair like underarm, pubic).
- Pubic region (coarse terminal hair).
- Eyelashes/eyebrows (short, protective hair).

### 5. What protein composes a strand of hair?
# Brief Explanations:
A hair strand is primarily composed of **keratin**, a fibrous structural protein. Keratin is tough, insoluble, and gives hair its strength, flexibility, and resistance to mechanical stress. It forms the main structural component of the hair shaft (cortex and cuticle), providing durability.
# Answer:
A strand of hair is composed of the protein **keratin**.

### 6. What are some ways that hair can be destroyed?
# Brief Explanations:
Hair can be destroyed by:
- **Physical damage**: Heat (e.g., excessive styling tools, fire), mechanical trauma (e.g., brushing, cutting, pulling).
- **Chemical damage**: Strong acids/bases (corrode keratin), bleaches/dyes (alter structure), or harsh detergents (strip moisture, weaken strands).
- **Biological factors**: Decomposition (by bacteria/fungi in moist environments), or animal activity (e.g., insects feeding on hair).
# Answer:
Hair can be destroyed by:
1. Physical means: Heat (styling tools, fire), mechanical damage (brushing, cutting, pulling).
2. Chemical means: Strong acids/bases, bleaches/dyes, harsh chemicals.
3. Biological means: Decomposition (bacteria/fungi), insect damage.

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QUESTION IMAGE

Question

Explanation:

1. In what two ways can hair evidence be classified?

Answer:

2. How can hair be useful to investigators if the follicle is not present?