Study carefully specimens C, D and E and use them to answer questions 2(a) to 2(c). (a) (i) State the mode of nutrition of specimen D. (ii) State one way by...
Question 1 Report
Study carefully specimens C, D and E and use them to answer questions 2(a) to 2(c).
(a) (i) State the mode of nutrition of specimen D.
(ii) State one way by which each of specimens C, D and E is of economic importance.
(b)(i) Classify specimens C, D and E into their phyla and classes.
(ii) List three observable characteristic features of each of the classes to which specimens C, D and E belong.
(iii) In a tabular form, state two observable differences between C and D.
(C) List four observable features of specimen E that are sensory in nature.
Answer Details
(a)(i) Mode of nutrition of specimen D (tick): parasitic (it sucks blood from its host).
(a)(ii) One way each is of economic importance
- C (grain weevil): it destroys stored grains and lowers their quality, reducing the farmer's income.
- D (tick): it infests cattle and dogs, sucking blood and making them anaemic, and it transmits diseases.
- E (rat): it destroys and contaminates stored food and spreads diseases.
(b)(i) Classification into phyla and classes
| Specimen | Phylum | Class |
|---|---|---|
| C (grain weevil) | Arthropoda | Insecta |
| D (tick) | Arthropoda | Arachnida |
| E (rat) | Chordata | Mammalia |
(b)(ii) Three observable characteristic features of each class
- Insecta (C): body in three divisions (head, thorax, abdomen); three pairs of jointed walking legs; a pair of antennae; compound eyes (and usually wings).
- Arachnida (D): body in two divisions (cephalothorax and abdomen); four pairs of legs; no antennae; simple eyes; feeding appendages (pedipalps and chelicerae).
- Mammalia (E): body covered with hair/fur; external ears (pinnae); mammary glands; four limbs; heterodont dentition.
(b)(iii) Two observable differences between C and D
| Specimen C (grain weevil) | Specimen D (tick) |
|---|---|
| Body in three divisions with a distinct thorax | Body in two divisions; thorax fused with head (cephalothorax) |
| Three pairs of legs; antennae present; wings present | Four pairs of legs; antennae absent; wings absent |
(c) Four observable sensory features of specimen E (rat): the eyes (sight), the external ears/pinnae (hearing), the nostrils (smell) and the whiskers (touch).
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