1. Fungi used to be thought as relatives of the plants. What features do they share with plants? Now, we know that fungi are actually more closely related to animals. Explain why.(3 points) 2. Explain, in your own words, the 4 possible steps of early cellular life on earth?(3 points) 3. "The evolution of plants has resulted in a trend of reduced size of the gametophyte generation." Explain this statement using moss ferns, and angiosperms as examples. Point out the structures involved. (3 points) 4. Why are animals like a centipede, a horseshoe crab and a barnacle which all look very different. considered to be in the same group? (3 points) 5. Which structure in the gymnosperm's is roughly equivalent to the anther in the angiosperms? Why?a Points) 6. When you worked on chapter 18 (Fig 18.4) you looked at nine different animal groups Explain why you would classify yourself as a chordate (we hope)and not another group (3 points) 7. "Annelids and arthropod:are the only groups of animals which are segmented." True or false"Why? (3 points) o

1. **Similarities between Fungi and Plants:** Fungi and plants share features like being sessile (immobile), having cell walls, and reproducing via spores. They also exhibit apical growth.<br /><br /> **Why Fungi are Closer to Animals:** Molecular data (DNA and RNA analysis) reveals a closer evolutionary relationship between fungi and animals. Both are heterotrophic (cannot produce their own food) and store carbohydrates as glycogen. Chitin, a component of fungal cell walls, is also found in the exoskeletons of some animals. Furthermore, the flagella in chytrid fungi (a primitive group) are similar in structure to animal flagella.<br /><br />2. **Four Possible Steps of Early Cellular Life:**<br /> 1. **Abiotic Synthesis of Organic Monomers:** Simple organic molecules like amino acids and nucleotides formed from inorganic precursors in the early Earth's environment (possibly aided by energy sources like lightning or hydrothermal vents).<br /> 2. **Polymerization:** These monomers combined to form larger polymers, such as proteins and nucleic acids. This might have occurred on the surface of clay minerals or in hydrothermal vents.<br /> 3. **Protocells:** Membranes formed around clusters of these polymers, creating protocells – precursors to the first true cells. These membranes provided a separate internal environment and allowed for more complex chemical reactions to occur.<br /> 4. **Self-Replication:** The development of a self-replicating molecule, likely RNA, allowed for the inheritance of genetic information and the beginning of Darwinian evolution.<br /><br />3. **Reduced Gametophyte Size in Plant Evolution:** The evolutionary trend in plants shows a progressive reduction in the size and dominance of the gametophyte (haploid) generation and an increase in the sporophyte (diploid) generation.<br /><br /> * **Moss:** The dominant generation is the gametophyte (the leafy green part we typically recognize). The sporophyte is smaller and dependent on the gametophyte.<br /> * **Ferns:** The sporophyte (the leafy frond) is the dominant generation. The gametophyte (a small, heart-shaped structure called a prothallus) is independent but much smaller than the sporophyte.<br /> * **Angiosperms (flowering plants):** The sporophyte is the dominant generation (the plant we see). The gametophyte is extremely reduced and entirely dependent on the sporophyte. The male gametophyte is the pollen grain, and the female gametophyte is the embryo sac within the ovule.<br /><br />4. **Classification of Centipede, Horseshoe Crab, and Barnacle:** Despite their different appearances, these animals are all classified as arthropods because they share key characteristics: a segmented body, a hard exoskeleton made of chitin, jointed appendages, and bilateral symmetry. These shared derived characteristics indicate a common ancestor.<br /><br />5. **Gymnosperm Structure Equivalent to Anther:** The **pollen cone (or microstrobilus)** in gymnosperms is roughly equivalent to the anther in angiosperms. Both structures produce pollen grains, which contain the male gametophytes.<br /><br />6. **Classification as a Chordate:** Humans are classified as chordates because we possess the four key characteristics of the phylum Chordata at some point in our development: a notochord (replaced by the vertebral column in vertebrates), a dorsal hollow nerve cord (develops into the brain and spinal cord), pharyngeal slits (present in embryonic stages), and a post-anal tail (also present embryonically). These features distinguish chordates from other animal groups.<br /><br />7. **Segmentation in Annelids and Arthropods:** False. While annelids and arthropods are segmented, they are not the *only* segmented animals. Chordates also exhibit segmentation, evident in the vertebrae of the spine, the arrangement of muscles, and the segmental nerves branching off the spinal cord.<br />