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Theme: The cell
Competencies
Competence in Linguistic Communication
Mathematical competence in science, technology and engineering
Personal, social and learning to learn competence
Subjects and year by Educational System
Spain > Biology and geology > 4th ESO > The cell
Enunciation
We owe the theory of endosymbiosis to Lynn Margulis. This theory explains the emergence of eukaryotic cells from primitive prokaryotic organisms. The following diagram summarizes the theory:
Figure 1: Events that supposedly led to the appearance of mitochondria and chloroplasts. Occurred through two independent processes of endosymbiosis, or primary endosymbiosis.Taken from: https://mmegias.webs.uvigo.es/02-english/5-celulas/1-endosimbiosis.php
Figure 2: Comparative structure of prokaryotes, chloroplasts and mitochondria.Taken from:http://www.biologia.edu.ar/botanica/tema8/8-3organulo.htm#Fig%2016
Look at the two figures above and answer the following questions:
1. What similarities do you see in the structure of chloroplasts, mitochondria, and bacteria?
2. Look at figure 1 and determine:
a. How many endosymbioses gave rise to animal cells?
b. How many were necessary to originate plant cells?
3. Based on the above: Where do mitochondria come from? And chloroplasts?
4. Will plant cells have mitochondria?
5. Briefly explain Lynn Margulis's theory of endosymbiosis, indicating what clues could have led her to propose such a theory. Why do you think it is called endosymbiosis and not just symbiosis?
Observations and context
Lynn Margulis was a contemporary of the astronomers Carl Sagan and Robert Whitaker, with whom she proposed a new classification of living things into five kingdoms.
Lynn Margulis is one of the scientists who have contributed with her proposals to the development of evolutionary biology. Some of them, such as Antoinette Brown Blacwell, dared to question some of Darwin's conclusions, who considered that "evolution had made men superior to women." Others like Barbara McClintock or Esther Lederberg discovered transposable genetic elements and horizontal gene transfer in bacteria, respectively. These discoveries have subsequently been of great importance to understand evolution.
Description
This is a short question and answer activity on the theory of endosymbiosis. Objective: Students have to deduce and write the most significant statements of said theory through the interpretation of drawings.