Chapter 25: The History of Life on Earth Flashcards
What is MACROEVOLUTION? how is it often revealed?
evolutionary change above the species level
often revealed through the fossil record
What are the 4 main stages that lead to the creation of the first cell?
- monomer (the abiotic synthesis of small molecules such as amino acids and nitrogenous bases)
- polymer (the joining of these small molecules into macromolecules such as proteins and nucleic acids)
- protocells
- cells that were self replicating (DNA)
What are PROTOCELLS?
droplets with membranes that maintained internal chemistry that was different from that of their surroundings
What is RADIOMETRIC DATING?
a technique of dating rocks and fossils based on the fixed rate of radioactive decay
What is a HALF-LIFE?
the time required for 50% of the parent isotope to decay
How old is a fossil that has 1/4 of the parent isotope left?
multiply 5730 (the half life of carbon) by 2
1 to 1/2 is the first half lie
1/2 to 1/4 is the second half life
What is a PROKARYOTE cell?
a type of cell lacking membrane bound organelles
What were the first cells to develop?
prokaryote
How did prokaryotes obtain energy?
the sun
What did the increase of prokaryotes using the suns energy lead to?
the oxygen revolution
What is a eukaryotic cell? how did they evolve
a cell that has membrane bound organelles, evolved through endosymbiosis and infolding
What is ENDOSYMIOSIS?
a relationship between two species in which and organism lives inside the cell to cells to another organism
What did EDOSYMBIOSIS give rise to?
chloroplasts, mitochandra, and plastids
What is serial endosymbiosis?
a hypothesis for the origin of eukaryotes consisting of a sequence of endosymbiotic events
What did infolding lead to?
nuclear membrane and ER
Why is multicellularity important?
lead to specialization
What is the hypothesis for multicellularity?
unicellular organisms became sticking together in colonies known as a volvox
What was the CAMBRIAN EXPLOSION and why is it important?
the Cambrian was a time about 525-535 million years ago in which many present day phyla emerged in a short period of time
important because this is where we first see hard bodied, large animals and HUNTERS EMERGE along with PREY DEFENSE
When was the colonization of land for Fungi, anthropods, and plants?
420 million years ago
When was the colonization of land for tetrapods?
365 million years ago
What is CONTINENTAL DRIFT?
the movement of plates floating on the earth’s crust
What does continental drift promote?
allopatric speciation on a grand scale
What was the importance of the PERMIAN MASS EXTINCTION and around when did it occur?
most expensive extinction (96% all species wiped out)
250 m.y.a
What was the importance of the CRETACEOUS EXTINCTION?
most famous and well studied extinction (wiped out dinosaurs but placental mammals start flourishing right after)
65 m.y.a
What are ADAPTIVE RADIATIONS?
a period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological niches in their communities
What is an example of WORLDWIDE ADAPTIVE RADIATION?
mammals underwent dramatic diversification/adaptive radiation after the extinction of the dinosaurs
What are the 3 types of mammals (cynodont)?
placental
monotremes
marsupials
what is an example of REGIONAL ADAPTIVE RADIATION?
the silverswords alliance (the plants of hawaii that are all different but came from the same plant - tarweed)
also house flies
what often initiates REGIONAL ADAPTIVE RADIATION?
the founder effect
What are the 3 trends seen through the fossil records of horses?
- larger
- complex molar teeth
- fewer toes
Evolution is like a mechanic not and engineer. T or F?
T
What is an example of evolution not being goal oriented?
the mollusk eye
from the slides: The mollusk eye illustrates this. Although the mollusk eye is very similar to the vertebrate eye in its complexity, it is actually better because the photoreceptors of vertebrate eyes point backwards causing blind spots. Mollusks’ photoreceptors face forward; thus, they have better eyesight. This illustrates that although both of these animals evolved complex eyes independently, the vertebrate’s eye evolved with what was available, not what is the best design.
