Answer problem 2 and 3 Part C: Arrange each chordate innovation in order of evol
ID: 212060 • Letter: A
Question
Answer problem 2 and 3 Part C: Arrange each chordate innovation in order of evolutionary appearance (from earliest to most recent) I)jaws 2) limbs 3) post-anal tail 4) vertebrae Problem 2. Compare and contrast the (sexual) life cycle of a moss with that of a flowering plant. For full credit, be sure to use each of the following terms in your answer: alternation of generations, antheridium (or antheridia), archegonium (or archegonia), diploid, double fertilization, endosperm, gametophyte, haploid, heterospory. mitosis, meiosis, sporophyte. o Vo dominant uhile in Floweving plant isgometphgte Cn theriolium in moss produce uie Pollen msle aamefo 8 uhile in Flou eving plan gotr n Floucrin pnt (orary) Pro ouce rule t he 279 tc in mes and Floserin plent, in me5s t heic e a enylosfewn , tinere is no endoyenn in mossound in flow
Explanation / Answer
Hi,
2. The mosses are most commonly seen in gardens and in forests. The moss what we see is the gametophytic generation. Mosses have two distinct spores, (Heterosporous), which develop into male and female gametophytes. The male gametophyte develops into antheridia and it produces sperms. The female gametophytes develop into archegonia and produce eggs. This embryo and sperm will sexually fuse to form sporophytes. These sporophytes are haploid and can germinate to form male and female gametophytes. Thus a major part of their life cycle they are haploid. The gametophytes are photosynthetic similar to flowering plants. Another common feature with flowering plants is the production of sperms and eggs by meiosis.
The flowering plants have basically diploid life cycle with reduced gametophytic generation. Majority of plant cells divide by mitosis, in common with mosses. Only the production of sex cells takes place using meiosis. These plants have specialized organ to carry out the formation of sporophytes. i. e called a flower. The flower is unique to angiosperms and not found in mosses. The mature sporophytes or seed also has a seed coat. Such structures are absent in mosses. The formation of the embryo is a bit complicated in angiosperms with a double fertilization. This results in 3N condition, which develops into endocarp. Endocarp is the protective layer for seed to nourish it during germination.
3.
The nematods and arthropods are now classfiied under ecdysozoans.
THe most common characters shared by these two groups is the three layered cuticle (Exoskeleton). These are periodically motled and renewed. This is called ecdysis. They do not have cilia for locomotion, and produce amoeboid sperm.