Question

Food chains are typically quite short, with only 4-5 links. Which of the following explains why? Only one species of herbivore feeds on each producer species. Predator species are usually less diverse and less abundant than prey species. Most of the energy at each trophic level is lost rather than passing on to the next level. Extinction of species at one level causes extinctions at higher levels. 1 points

QUESTION 47 Which of the following is a characteristic of all chordates at some point during their life cycle? vertebrae four limbs four-chambered heart jaws post-anal tail 1 points

QUESTION 48 Which of these is a major trend in land plant evolution? the trend toward larger gametophytes the trend toward smaller size the trend toward a gametophyte-dominated life cycle the trend toward a sporophyte-dominated life cycle 1 points

QUESTION 49 The phytochrome system is involved in which of the following plant responses? none of the responses involve the phytochrome system photoperiodism all of these responses involve the phytochrome system negative phototropism positive phtotropism 1 points

QUESTION 50 Approximately how many kilocalories (kcal) of a secondary consumer's energy requirements can be supported by a community containing 100 kcal of producers? 0.1 kcal 10 kcal 1 kcal 0.01 kcal 1 points

QUESTION 51 Vertebrates and urochordates share which of the following traits? a high degree of cephalization (i.e., a well-developed head) a notochord and a dorsal, hollow nerve cord vertebral column jaws adapted for feeding

Answer 1

46. The correct option is Most of the energy at each trophic level is lost rather than passing on to the next level. This is the appropriate reason for short food chains. And only 10% of the energy is available to the next level.

47. The correct option is Post anal tail. This is a common character found in all chordates at some point during their life cycle. Apart from this, they also share other common characters like notochord, dorsal hollow nerve cord and pharyngeal slits.

48. The correct option is the trend toward a sporophyte dominated life cycle. With evolution of lower plants like algae to most advanced land plants, there is reduced gametophyte and enhanced sporophyte.

49. The correct option is photoperiodism. The phytochromes are photoreceptors that sense change in photoperiods which later act as flowering signal for a plant.

50. The correct option is 1kCal. According to the 10% rule, 1kCal of energy is available to the secondary consumer and 10kCal to primary consumer if the producer generates 100kCal of energy.

51. The correct option is a notochord and a dorsal hollow nerve cord. This is the common character between an urochord and a vertebrate.