BIOL 122- Organisms and Their Environment

Exam 2

What is the Endosymbiotic Theory, and what are two lines of eviidence that support it?

1) The endosymbiotic theory is the theory that an early eukaryotic cell engulfed two bacteria that were endosymbiotic with the cell, and they all worked together to better each other. Over time, the cells became reliant on each other to the point that the two engulfed bacteria became the mitochondria and the chloroplast.

2) Both the mitochondria and the chloroplast have their own Ribosomes and DNA. Also they both have a double membrane.

What is the amniotic egg? Why is it important for understanding the transition from water-to-land in Chordates?

1) The amniotic egg is an egg with an outer shell( but not always, in humans and mammals) and amniotic fluid on the inside of the egg. The outside of the egg keeps the egg from drying out, and the amniotic fluid serves a similar purpose to a pond would for a frog egg. The amniotic egg also has a yolk food source and areas for waste.

2) is important because it allows land animals to fully leave water for development, because the amniotic fluid is the water.

SA:V gets smaller as an organism gets larger. this change happens because…

Volume is growing at a faster rate than surface area. Volume is x3 where as surface is x2.

What are the 4 unifying characteristics of all Chordates?

1) notochord

2) Dorsal hallow nerve Chord

3) Gill slits

4) post anal tail