Explanations
Explanations

1.      A     

All monerans are prokaryotes. Bacteria commonly have cell walls, but so do other organisms, such as in kingdoms Fungi and Plantae. Radial cleavage is a characteristic found in kingdom Animalia, and angiosperms and gymnosperms are distinctions within the Plantae kingdom.

2.      A      

Autotrophic (“self-feeding”) organisms produce their own organic nutrients, using energy from sunlight (photosynthesis) or chemical energy (chemosynthesis). Heterotrophic (“other-feeding”) organisms must consume the organic nutrients in other living organisms. Fungi are heterotrophic organisms.

3.      B     

Fungi have chitinous cell walls. Spiders are arthropods, which have chitin incorporated into the exoskeleton. Like all animals, however, the cells of spiders do not have cell walls. The euglena and cnidarian do not possess cell walls. Protist molds and bryophytes both have cell walls made of cellulose.

4.      A     

Taxonomists use body symmetry (e.g., bilateral vs. radial), patterns of embryonic development (e.g., spiral vs. radial cleavage), similarity of molecular clocks (e.g., cytochrome c), and complexity of tissue organization (particularly development of sensory organs and nervous tissue). Motility is characteristic of organisms in various kingdoms and is not used to determine evolutionary relationships among animals.

5.      E     

Bryophytes reproduce using single-celled spores rather than seeds. Spores require a flagellated male gamete to travel through water for fertilization. Seeds contain both a complete embryo and a food supply, allowing the embryo to grow independently of outside food sources when it is smallest and most vulnerable. Also, the male gamete of seed plants is pollen, which can travel through the air. The vascular system has allowed plants to grow larger and develop different parts with specialized functions. Flowers and fruits increase the efficiency of reproduction by recruiting animals into pollen and seed distribution. Animals spread pollen and seeds in a more targeted fashion, and to a wider area, than wind or water usually do.

6.      D     

The heterotroph hypothesis suggests that anaerobic heterotropic organisms may have evolved first, releasing carbon compounds into the atmosphere and allowing the process of photosynthesis to evolve. Autotrophs then consumed the carbon dioxide. The oxygen released as waste facilitated the evolution of aerobic organisms. It would not make sense that anaerobic and aerobic organisms would evolve together. The latter would thrive in an oxygen-rich atmosphere, and the former would rely on other molecules. Autotrophs require carbon dioxide, which was not available in great quantity in the ancient atmosphere of the Earth. Chemosynthesis is an autotrophic process and did not contribute to the evolution of heterotrophs.

7.      D     

Lamarck argued that gradual changes acquired by individuals over a lifetime were passed on to offspring. Use enhanced or amplified a trait while disuse reduced it. Lamarck did not discuss the idea of recessive inheritance, and natural selection was an element of Darwinian evolution.

8.      A     

When a population is unable to interbreed, speciation occurs. Adaptive radiation is a specific type of speciation, but it refers to speciation that occurs by means of competition for a niche, not through geographical isolation. Convergent evolution occurs when two different species that have some similar functions develop similar-looking body parts. Natural selection is always happening; the diversion of the river does not begin natural selection. Lamarckian evolution never occurs, since it is an incorrect theory.

9.      C     

The situation described in the question only covers one generation of penguins. Evolution and speciation take a lot more time than one generation to begin to function, but natural selection occurs within a generation by picking out the most fit individuals.

10.      D     

Of the organisms in the answer choices, only birds and reptiles lay hard eggs. Reptiles do not provide parental care for their young, while birds do.

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