Marine Ecology Evolution and Prehistoric Oceans

Chemical Evolution
Organic molecules, biopolymers, and systems of chemical reaction were first necessary to form the first protocols took about one billion years.
Alexander Opairin
Russian Biochemist, first hypothesized that energy from lighting and volcanoes and intense UV light created first organic molecules from inorganic chemicals.
Biological Evolution
change in populations genetics make up through successive generation
describes long-term, large-scale evolutionary changes among groups of species
Natural Selection
individuals of a population have genetically based traits this helps better survive and produce offspring.
Selective pressure
Causes natural selection to occur
Charles Darwin
Developed the concept of Natural Selection in 1846 was published on the Origin of Species by Means of Natural Selection (1859).
Natural Selection Three conditions
-natural variability of a trait within a population
- The trait is heritable
- The trait leads to differential reproduction
Direction Natural Selection
causes allele (gene forms) frequencies to shift toward one end of the normal range eliminating the other end.
Stabilizing Natural selection
causes allele frequencies to shift toward the middle of the normal range, eliminating both ends.
Diversifying natural selection
causes allele frequencies to shift toward both ends, eliminating the middle.
Vestigial structures
reoccurrence of traits (Through Mutation) that were selected against
Transitional Forms

dying of a whole species due to the change in environmental conditions
How much percent of species are now extinct?
99% of all species that existed are all extinct
Speciation and Extinction affected by several major factors
Large scale movements of continents, Gradual climate changes, Rapid Climate change, Human influence
Background Extinction
This is the average extinction rate of (1-10 species) a year who go extinct without any human interference.
Mass Extinction
Abrupt rise in extinction rates above the background level
How many extinctions in earth's history ?
Five Major mass extinctions
Largest Mass Extinction?
Permian, 250 million years ago caused disappearance of 90% of marine species.
Most recent Mass extinction?
Cretaceous, 65 million years ago marking the end of the dinosaurs
Study fossils to learn about Earth's history
Fossil remains
provide the previous geological time that provides clues for climate and geological events as well as evolution.
Fossils are found in what kind of rock?
Sedimentary Rock
Trace Fossils
These are parts, footprints, or burrows etc.
caused by drying , often in the desert
hardened tree sap
Tar Beds
Thick petroleum at surface ( La Brea Tar Pit in CA 15,000 years old
often done in cold areas such as Siberia
Mineral solutions (Ground water) replace original organic materials
molds, casts other types of trace fossils
Fossilized dung or waste (Poop!)
Fossilized digestive stones or eggs
Index fossils
are found in rock layers of a particular geological age
are 245-570 million years old
Precambrian Time period?
4.6 BYA- 570 MYA
4.6 BYA
Earth was formed Early atmosphere was Water vapor,
4.2 BYA
Ocean formed as the planet cooled and Water vapor condensed
3.6 BYA
First evidence of life, cyanobacteria
2.5 BYA
Oxygen began to accumulate in the atmosphere
570 MYA-248 MYA
490 MYA
Brachiopods, Cephalopods and trilobites dominate
443 MYA- 354 MYA
The Devonian Period is known as the Age of the Fishes
End of Paleozoic
Supercontinent Pangea was formed and species began to move into island
250 MYA
- Large scale climatic changes led to the Permian extinction wiping out 90% of marine species
Mesozoic Era
248 MYA- 65 MYA (AGE OF REPTILES) Dinosaurs dominate the land
200 MYA
Pangaea breaks up and continents begin to move to their current locations.
65 MYA
The Mesozoic ended with the Cretacious extinction event. It was caused by a large asteroid hit off the Yucatan Peninsula in Gulf of Mexico
Age of Mammals, mammals replace reptiles as the dominant land animals
First Marine Mammals
appear 50 Mya evolving from land mammal Ambulocetus
evolved 2.5 MYA, with modern Homo sapiens appearing 250,000 years ago, Humans began impacting the ocean in the last 200 years primarily through overfishing and pollution.
Coelacanths (Latimeria chalumnae and Latimeria menadoensis)
With only two extant species, coelacanths are known as "living fossils" and were only discovered recently (1998). They can grow to be over 2 meters long, and have unique hollow spine fins.
Atlantic Horseshoe Crab (Limulus polyphemus)
Despite the name, horseshoe crabs are more closely related to spiders than crabs. They evolved 250-500 million years ago with blood containing hemocyanin (as opposed to our hemoglobin) which turns their blood blue when exposed to oxygen.
Megalodon (Carcharodon megalodon)
Megalodon was one of the most powerful predators in history. Its phylogeny was similar to a great white, but megalodon grew to be almost 60 feet long.
Trilobites (Order Trilobita):
Trilobites are an ancient class of Arthropod that consisted of more than 20,000 species. They were a dominant group in the Paleozoic Era and they were particularly important in the development of the concept of punctuated equilibrium by Gould and Eldridge.
Nautilus (Family Nautilidae):
There are six extant species of Nautilus and they are often considered living fossils since they have remained relatively unchanged in 500 millions years. They are most closely related to squid and octopus, though those groups have obviously lost the external shell that is evident in the Nautilus.
Plesiosaur (Order Plesiosaurus):
Plesiosaurs, which are often mistakenly called dinosaurs, are prehistoric marine reptiles that lived at the same time as dinosaurs. Species in this genus ranged from 2 meters to 20 meters in length and they all lived in shallow seas along continental shelves.
Helicoprion (Helicoprion sp.):
The genus of Helicoprion sharks are known for their bizarre tooth whorls which looked like buzzsaws. These spirals of teeth were most likely located in the throat, though some renderings have placed these strange structures on the bottom jaw. The exact placement is unclear because the cartilage skeleton of a shark does not fossilize well.
Fossil (Definition)
remains of an organisms
Extinction (Definition)
Death of a whole complete Species
Pangae (Definition)
Hypothetical Supercontinent together with current land masses
Period of time
Age of Fishes (Definition)
The Devonian is a geological period during paleozoic also known as Age of Fishes
Major evolutionary change longterm and large scale
Natural Selection (Definition)
Survival of the fittest
Chemical Evolution (Definition)
chemical reactions in ocean during the early history of earth the first step in devolopment of life in this planet. lasted less than a billion years
Vestigial Structure (Definition)
structure in an organism that has lost all or most of its original function in the course of evolution
Age of Mammals (Definition)
Cenozoic Period
1. Which of the following gases were not present in large amounts in the early Earth atmosphere?
a. water vapor
b. carbon dioxide
c. nitrogen
d. oxygen
D. Oxygen
What conditions are more likely to preserve an organism as a fossil?
a. organism with hard parts and slow burial
b. soft-bodied organism and slow burial
c. organism with hard parts and rapid burial
d. soft-bodied organism and rapid burial
C. Rapid Burial and Organism with hard parts
3. Fossils are important because they provide evidence for
a. ancient climate
b. geologic events
c. evolution
d. all of these answers
d. all of these answers