Period  4, 7:

1. Review of the Hardy-Weinberg / Chi – Squared Quiz that was handed out yesterday.

2. Speciation slides from HW to Selective mating.

b)  Artemia / Brine Shrimp lab data collection – day 2 – 48 hour period

___________________________________________________________________                                                                             Jump to:   top             10/21 – Wednesday’s Homework: – 

1. Please use the form as your guide to view the following videos and complete the form:                          

The following videos are used to complete the form below.  I will direct you to each video in the form. 

Today’s Connections:

Photosynthesis: What mostly plants do: Convert CO₂ into O₂.

                 6CO₂ (g)  +  6H₂O (l) → 6O₂ (g)  +  C₆H₁₂O₆ (s)

During the Cretaceous Period there was very large carbon dioxide levels, from flood basalts, BUT there was a great number of plants to absorb it and convert it to oxygen to maintain high oxygen levels that prevent the microbial takeover that produce hydrogen sulfide.

A gas mask of hydrogen sulfide has the potential to save lives in the future because humans have adapted to have a tolerance for hydrogen sulfide. This was probably a selective pressure that allowed mammals to survive both the Permian and Triassic mass extinctions.  Hydrogen sulfide slows down the metabolism and mimics “cold blooded” organisms metabolism who use the environment to maintain their metabolism. Warm blooded organisms spend a lot of energy keeping their own metabolism (temperature high) no matter what the temperature is in the environment and are selected for in colder climates. Coldblooded animals spend far less energy on their metabolism and thus are selected for in warm climates.

Based on the Kump hypothesis, the Permian,  Triassic, and, and KT occurred because of a trigger of increased carbon dioxide that lead to a microbial take-over that produced hydrogen sulfide.  The increased carbon dioxide, will increases the acidity in our oceans that will kill out plankton layer, which is responsible for producing most of our oxygen and all of the food in our oceans. Phytoplankton, the plankton that uses photosynthesis to produce the organic material for life in out oceans. Photosynthesis takes in carbon dioxide and water and produced organic matter (food) for the rest of the ocean AND releases OXYGEN for the rest of us!! Also the increased warming of the poles (ice caps) will decrease the ocean currents and make our oceans more stagnant which will decrease oxygen levels even more.  The loss of oxygen will allow the hydrogen sulfide microbes to increase in number as they cannot survive with oxygen.

Mammals or their most recent ancestors WHO ALREADY HAD had a mutation that increased reproductive fitness by allowing them to move slower and require less oxygen (less of it was available due to the death of phytoplankton). Only the small mammal ancestors survived as larger mammals who started to dominate the landscape as the biggest creatures on the planet BEFORE the dinosaurs perished because of there LARGER oxygen requirement NEEDED FOR LARGER ENERGY NEEDS to keep their larger bodies maintaining a higher metabolism.

The hydrogen sulfide has the ability to cool down the body long enough to keep a person alive for critical care. A person who is given hydrogen sulfide will come out of it perfectly fine, with the exception of lost brain tissue. However, in a choice between living and loss of brain tissue, losing brain tissue seems like a more advantageous option. This as not an issue with early mammals because their brains were smaller.

The dinosaurs’s were a mistake or chance event that should never dominated the landscape as they needed a certain set of conditions to be just right for the evolution to occur. Obviously, they had the conditions (very high temperatures and vast plant  diversity and growth) that suited them for the tremendous amount of evolution that occurred BUT they were always going to be doomed.

During the Cretaceous Period they was a lot of continental plates moving and thus a lot of volcanic activity releasing large amounts of carbon dioxide, CO2.  CO2 is a greenhouse gas and greater concentrations contributed to larger average temperatures (+10º F) that supported cold blooded animals and greater plant growth.  Do not forget all energy in ecosystems start with plants!  The amount and health of plants needed to be great to support the very large creatures that dinosaurs became. Greater CO2 levels also acts a fertilizer that contributed to greater plant growth. Greater plant growth supports greater dinosaur evolution and growth.  Because they had hollow bones, did not need to expend energy like warmblooded animals to maintain metabolism, reproduced very frequently, and had tremendous food resources,  they were selected to evolve for these conditions.  They lived in very unique conditions that the earth could not support forever.  The KT event brought a quick end to the Cretaceous Period that was going to end at some later point anyway.

Dinosaurs evolved very quickly to in these very unique conditions and thus were doomed because they did not have the alleles to survive in colder climates ( cold blooded ) with less vegetation (many were so large). 

The pre- mammals (lizard – mammals) were dominating the landscape long before the dinosaurs who could never survive today and the Permian extinction was a stroke of luck for the dinosaurs BUT only prolonged the mammals eventual domination.

These are examples of pre-mammals that existed long before the dinosaurs and they GET NO LOVE!!!!!

as compared to the dinosaurs….

Give these pre-mammals SOME LOVE!!!

Gorgonopsia – reptilian mammal/ endothermia

1.   Make another submission to the Plankton form posted on Wednesday if needed.

2.   Please use the Evolution Presentation and the Origin of Life Presentation Presentation to complete the form below: