Biology 203 1st Edition Lecture 10 Outline of Last Lecture I. Why Care About Algae?II. About AlgaeIII. StramenopilesIV. RhizariaV. Alveolata Outline of Current Lecture I. About Land PlantsII. How did land plants adapt to live on land?III. HepaticophytaIV. Vascular tissues are the next major adaptationCurrent LectureI. About Land Plantsa. Diversification in lineages giving rise to Bacteria and Archaea starts much earlier than diversification of Eukaryab. Limitations of diversity estimates based on named speciesc. Diversification of Fungi and Animals predates that of Land Plantsd. Land plants are a monophyletic group whose common ancestor was an Archaeplastid organism that made it onto landII. How did land plants adapt to live on land?a. How to allow for nutrient absorption without drying out?i. In algae, water and nutrients could move into the body on all surfacesii. On land, a water-proof cuticle (wax) prevents evaporation from upper surfaceiii. Water and nutrients still move up through bottom sideb. How to deal with that horrible UV-radiation source in the sky?i. In algae, water absorbs and scatters most of the UV light and prevents damage of DNA and other cellular componentsii. On land, plants are exposed to more UV lightiii. Cuticle also solves this problemiv. Wax layers scatter UV light and contain other “sunscreen” compoundsc. How to maintain gas exchange with that wax on upper surface?These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.i. Specialized epidermal cells, called guard cells, form an opening (stomata) which plants can open and closeii. Lets plants prevent water loss in dry conditionsIII. Hepaticophytaa. Liverwortsb. Liverworts retain many of the characteristics seen in the earliest land plant fossilsc. But that does not make them “ancient” or “less evolvedd. Liverwort reproductioni. Reproduce sexually using ornate structuresii. Reproduce asexually using gemma cupsIV. Vascular tissues are the next major adaptation found in the fossil recorda. Reproduce sexually using ornate structuresb. Reproduce asexually using gemma cupsc. Vascular tissues also allowed for the development of woody growth formsd. Extinct species of the Lycophyta and Pteridophyta formed the earth’s first
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