BIO 200 Lecture Notes - Lecture 7: Gymnosperm, Phloem, Marchantiophyta
19 Jun 2015
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Bio 200_ evolutionary biology-lecture 7: origin of eukaryotes, protists, and land plants. Eukaryotes arose between 2. 7 and 1. 7 billion years ago. A protist was the first eukaryote and this was a huge event on earth. There is chemical evidence of protist life from 2. 7 billion years ago but there is not a fossil until a billion years later. Multicellularity: allows for flexibility with dealing with the environment in different ways. Sexual reproduction (almost all): leads to increased genetic diversity because of new gene combination. This shows different organelles that carry independent functions. A result of membrane enfolding and the engulfment of other cells and adopting their functions (once prokaryote species introduced into the cell) It was the loss of the rigid cell wall and the enfolding of the cell membrane. This added surface area and increased the cell volume. The origin of the nucleus and endoplasmic reticulum: The image below is unclear so here are the steps:
