Notes 1-5

Notes 1-5 - Bio Sci 1C - Winter quarter, 2008 Notes for...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Bio Sci 1C - Winter quarter, 2008 Notes for lectures 1-5 (January 8, 9, 10, 14 & 15) 1. All organisms discussed in the course will have cell walls . While we will focus on the highly-evolved flowering plants, four major groups of walled organisms will be discussed. In the first edition of the text used in BIS 1C, all living things were identified as being members of one of 5 Kingdoms . The implication of grouping these organisms in Kingdoms was that researchers who had been studying the evolutionary relationships between organisms (the science of Systematics ) had concluded that all members of a given Kingdom were related to a single common ancestor, an organism that was not an ancestor of the members of another of the so-called kingdoms. The five Kingdoms were Monera (the bacteria, including blue-green algae), the Fungi , the Animalia (animals), the Plantae (plants), and the Protista (including organisms thought to be the ancestors of fungi, plants and animals; this means true algae, protozoans, slime molds and foraminiferans). More recent evidence, discussed in Chapter 1 of the current (2 nd ) edition of the text and about which you will hear more in lecture 33, has led to the conclusion that the “Five Kingdoms” classification system for all living things does not reflect natural, evolutionary relationships. There were two major problems with 5 Kingdoms classification. (1) The Protista included a variety of organisms that were clearly not evolutionarily related to one another and (2) there were two large groups included in the bacteria and growing evidence related to the similarities and differences in key DNA sequences was suggesting that the evolutionary differences between these two groups of bacteria could be greater than the evolutionary differences between current animals, fungi, “protista” and plants. The currently accepted relationships are illustrated in Figure 18.3 in edition 2 of the text. All organisms are now grouped into three domains . A. Two of these domains are called Bacteria and Archaea. These organisms are prokaryotes. This means their cells do not have distinct nuclei (the Greek word karyon means " nut ", the prefix " pro " implies something that comes before). Prokaryotic organisms have most or all of their genetic material (DNA) organized into a circular molecule and that DNA is not surrounded by a nuclear membrane as in the organisms in the third domain. Prokaryotic cells also lack distinct cellular organelles. As a group, the organisms in the Bacteria and Archaea have a great variety of metabolic processes. Some are autotrophic (that is, they are able to biochemically manufacture their own food from inorganic molecules, using energy that has been collected from environmental sources). The word trophic refers to the mode of obtaining food. The prefix " auto " refers to self. However, many of the prokaryotes can’t generate food for themselves, they are heterotrophic . The prefix hetero means "other"; the heterotrophs must get their food from
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/10/2008 for the course BIS 1c taught by Professor Maloof during the Winter '07 term at UC Davis.

Page1 / 14

Notes 1-5 - Bio Sci 1C - Winter quarter, 2008 Notes for...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online