Paleo Lab 8 - Paleobotany

Paleo Lab 8 - Paleobotany - PALEO LABORATORY # 8, PAGE 1...

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

View Full Document Right Arrow Icon
PALEO LABORATORY # 8, PAGE 1 PALEO LAB VIII - LAND PLANTS AND PALYNOLOGY The study of fossil protists and plants is conducted by micropaleontologists and paleobotanists. The field of paleobotany, involving the study of fossil plants, may be divided into a number of subdisciplines. This study involves four of the five kingdoms of organisms and encompasses both the study of large organisms and micropaleontology as well. Most of these organisms produce their energy by means of photosynthesis. We have discussed many of the smaller representatives of photosynthetic organisms during our micropaleontology lab. The lab here discusses the land plants; photosynthetic metazoans of the Kingdom Plantae. Kingdom Plantae It is believed that green land plants (Kingdom Plantae) evolved from ancestors belonging to the Chlorophyta (grass-green algae). Biochemical similarities between the two groups include the presence of chlorophylls a and b, true starch, and cellulose in their cell walls. The Kingdom Plantae include plants in which the fertilized egg develops into an embryo which is enclosed within a protective covering. Another characteristic of sexually reproducing green land plants is Alternation of Generations. In this there are multicellular gamete-producing organisms (Gametophytes) alternating in the life cycle with multicellular spore-producing organisms (Sporophytes). The Kingdom Plantae contains two morphological groups, the bryophytes (mosses, liverworts and hornworts) and the tracheophytes (vascular plants). Of the two, the tracheophytes are the most important paleontologically and include several divisions. Tracheophytes, or vascular plants, are characterized by the presence of conducting cells (xylem and phloem), and usually possess roots, stems and leaves. Roots are subterranean; the subaerial portions of plants are termed shoots. The xylem and phloem form the internal transport system that connects all parts of the plants. Other vascular plant characters include an external waxy covering (Cuticle) that aids in reducing desiccation, a high volume to surface ratio, and differentiation of the shoot system into stem, Foliage (leaves) and reproductive organs. Vascular Plant Structure Because of the presence of rigid tissues, tracheophytes can reach very large size. Also, due to the presence of these resistant conducting systems and waterproofing cuticle structure, vascular plants are more frequently fossilized than fungi, bryophytes and most algae. The conducting cylinder in the root and stem of vascular plants is termed the Stele. In the center of the stele there is typically an area of soft tissue that is used in food storage termed the Pith. Stems of many primitive land plants lack the pith and are termed Protostelic. However, most plants possess a pith that is surrounded by wood, or Xylem. The xylem is actually dead tissue through which water and minerals are transported. The principle food transport system, the Phloem, surrounds the xylem. However, as phloem transports sugars it is typically not
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.

Page1 / 8

Paleo Lab 8 - Paleobotany - PALEO LABORATORY # 8, PAGE 1...

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