Study specimens H and J and answer questions 2(a) to 2(d).
(a)i) Name the Kingdom and Class of organisms from which specimen H could be obtained.
(ii) Name the specific location on the body of the organism from which specimen H could be obtained.
(iii) Name one example of organism from which specimen H could be obtained.
(bi) State six observable structural differences between specimens H and J.
(c) State one function each of specimens H and J to the organisms that possess them. H:(ii) State three observable structural similarities between specimens H and J.
(d) Mention: (i) three observable features that adapt specimen H to the function stated against it in 2(c);
(i) two observable features that adapt specimen J to the function stated against it in 2(c).
Specimen H is a large stiff quill (flight) feather and specimen J is a soft fluffy down feather, both obtained from a bird.
(a)(i) Kingdom: Animalia; Class: Aves.
(a)(ii) Specific location on the body: the wing (or tail) of the bird.
(a)(iii) Example organism: domestic fowl (Gallus gallus); a pigeon is also acceptable.
(b)(i) Six observable structural differences between H and J:
| Specimen H (quill feather) | Specimen J (down feather) |
|---|
| Has a long, stiff shaft (rachis) | Has a short, soft shaft |
| Has a large, flat, well-formed vane | Has no distinct flat vane |
| Barbs are firmly interlocked by hooked barbules | Barbs are free and not interlocked |
| Firm and rigid in texture | Soft and fluffy in texture |
| Vane is asymmetrical (unequal on both sides) | Barbs are loose and roughly symmetrical |
| Larger in overall size | Smaller in overall size |
(c) Function of each specimen:
- H: provides the broad surface used for flight (pushing against air and streamlining the body).
- J: provides insulation, trapping air to conserve the bird's body heat.
(c)(ii) Three observable structural similarities between H and J:
- Both have a central shaft.
- Both bear barbs arising from the shaft.
- Both are made of the protein keratin (both possess a quill/calamus at the base).
(d)(i) Three features that adapt H to flight:
- A broad, flat vane giving a large surface area to push against air.
- Interlocking barbs and barbules forming a continuous, air-tight surface.
- A light, hollow shaft that reduces weight for easy lift.
(d)(ii) Two features that adapt J to insulation:
- Loose, non-interlocking barbs that trap a layer of still air.
- Soft, fluffy structure lying close to the body to hold warm air against the skin.
Specimen H is a large stiff quill (flight) feather and specimen J is a soft fluffy down feather, both obtained from a bird.
(a)(i) Kingdom: Animalia; Class: Aves.
(a)(ii) Specific location on the body: the wing (or tail) of the bird.
(a)(iii) Example organism: domestic fowl (Gallus gallus); a pigeon is also acceptable.
(b)(i) Six observable structural differences between H and J:
| Specimen H (quill feather) | Specimen J (down feather) |
|---|
| Has a long, stiff shaft (rachis) | Has a short, soft shaft |
| Has a large, flat, well-formed vane | Has no distinct flat vane |
| Barbs are firmly interlocked by hooked barbules | Barbs are free and not interlocked |
| Firm and rigid in texture | Soft and fluffy in texture |
| Vane is asymmetrical (unequal on both sides) | Barbs are loose and roughly symmetrical |
| Larger in overall size | Smaller in overall size |
(c) Function of each specimen:
- H: provides the broad surface used for flight (pushing against air and streamlining the body).
- J: provides insulation, trapping air to conserve the bird's body heat.
(c)(ii) Three observable structural similarities between H and J:
- Both have a central shaft.
- Both bear barbs arising from the shaft.
- Both are made of the protein keratin (both possess a quill/calamus at the base).
(d)(i) Three features that adapt H to flight:
- A broad, flat vane giving a large surface area to push against air.
- Interlocking barbs and barbules forming a continuous, air-tight surface.
- A light, hollow shaft that reduces weight for easy lift.
(d)(ii) Two features that adapt J to insulation:
- Loose, non-interlocking barbs that trap a layer of still air.
- Soft, fluffy structure lying close to the body to hold warm air against the skin.
