Answer:
The seed plants are often divided arbitrarily into two groups: the gymnosperms and the angiosperms. The basis for this distinction is that angiosperms produce flowers, while the gymnosperms do not.
Explanation:
The seed plants are often divided arbitrarily into two groups: the gymnosperms and the angiosperms. The basis for this distinction is that angiosperms produce flowers, while the gymnosperms do not. This is poor form, since it defines the gymnosperms by the absence of a character, and not by any features that the organisms actually share. The gymnosperms do share a number of features, but, as should be obvious from the above cladogram, they are not more closely related to each other than to the angiosperms (Anthophyta). The features shared by gymnosperms were likely present in the early ancestors of the flowering plants as well. It should also be noted that the "progymnosperms" are represented by a box of a different color, in order to make it clear that they are not actually seed plants, but rather are included here because they are believed to be the closest relatives of the seed plants.
Systematics within the seed plants is poorly understood. Part of the problem is that most of the major groups have gone extinct, and several of the groups alive today consist primarily of plants with highly derived morphologies. The above cladogram is based largely on the work of Jim Doyle, a professor at UC Davis, and Michael Donoghue, currently at Harvard, and is therefore somewhat preliminary. It includes some questionable groupings not explicitly supported in their papers.
Answer:
a) Humans depend upon other organisms for food and oxygen
Explanation:
Biodiversity refers to the richness in the species of organisms on Earth i.e the variety of biological organisms on the Earth. The importance of biodiversity cannot be overemphasized because of our dependence on the sustainability of biodiversity in our ecosystems.
The loss of biodiversity, which is becoming rampant by the day, is a major concern to us because we humans depend upon other organisms for food and oxygen. Humans are strictly heterotrophic and hence are reliant on variety of organisms for food. Plants also release oxygen gas via their photosynthetic process, which is key to our survival as a population.
Answer: false
Explanation:
Different parts of DNA are switched on or off to activate genes required for the cell specific function. Under certain conditions cells can de-differentiate, or express different genes e.g. cancer cells.
Answer:
The testes are oval organs about the size of very large olives that lie in the scrotum, secured at either end by a structure called the spermatic cord. Most men have two testes. The testes are responsible for making testosterone, the primary male sex hormone, and for producing sperm.
Explanation:
The pelvic bones are examples of vestigial structures.
