history of life worksheet

Flashcard maker : Charles Clay
Earth has formed 4.6 billion years ago
Geological events on Earth set up conditions that would play a major role in the evolution of life on Earth
By the end of the Mesozoic, the continents took on their modern shape
The first organisms appeared on land between 3.9 and 3.4 billion years ago
A footprint, trail or burrow, providing evidence of animal activity
Trace Fossil
A fossil embedded in tree sap, valuable because the organism is preserved intact
An exact stone copy of an original organism, the hard parts of which have been penetrated and replaced by minerals
Petrified Fossil
Any evidence of an organism that lived long ago
The fossil of a thin object, such as a leaf or feather, that falls into sediments and leaves an outline when the sediments harden
An empty space left in a rock, showing the exact shape of the organism that was buried and decayed there
An object formed when a mold is filled by minerals from the surrounding rock
If layers of rocks are left undisturbed the layers on top are younger because they formed after the layers on the bottom
Relative Dating
One fossil is older than another
What is the limitation of relative dating
Radiometric dating
How do paleontologist determine the specific age of a fossil
Compare amount of original radioactive element to amount of new element formed from decay
How do scientist use radiometric dating to determine the age of rocks or fossils
The first photosynthetic bacteria form dome-shaped structures called stromatolites
Primates evolve and diversify
Divided into three periods: Triassic, Jurassic, and Cretaceous
An explosion of life, characterized by the appearance of many types of invertebrates and plant phyla
Mammals appear
Dinosaurs roam earth, and the ancestors of modern birds evolve
Flowering plants appear
Amphibians and reptiles appear
Non-living matter, Spontaneous Generation
Early scientists believed that life arose from (1)____ through a process they called (2)___
Francesco Redi, disproved
In 1668, the Italian physician (3)___ conducted an experiment with flies that (4) _____ spontaneous generation
Microscope, microorganism, spontaneously
Biologist began to use an important new research tool the (5)___. They soon discovered the vast world of (6) ___. The number and diversity of these organisms was so great the the scientist were led to believe once again that these organisms must have arisen (7)___
Louis Pasteur, s-shaped, air, vital force, broth, organism, biogensis
By the mid 1800’s, however (8)____ was able to disproved spontaneous generation once and for all. He set up an experiment, using flasks with unique (9)___ necks. These flasks allowed (10)___, but no organisms to come into contact with a broth containing nutrients. If some (11)___existed, as had been suggested, it would be able to get into the (12)___through the open neck of the flask. His experiment proved that organisms arise only from other (13)___. This idea is called (14)___ is one of the cornerstone of biology today
does not explain
Biogensis (explains)
For life to begin, simple (inorganic) molecules had to be formed an then organized into complex molecules
several billion years ago, earths atmosphere had no free (methane)
Primitive earths atmosphere may have been composed of water vapor, carbon dioxide and (nitrogen)
in the early 1900s, Alexander Oparin proposed a widely accepted hypothesis that life began on (land)
(Pasture) hypothesized that many chemical reactions occurring in the atmosphere resulted in the formation of primordial soup
in 1953 Miller and Urey tested Oparins hypothesis by simulated the conditions of (modern) earth in the laboratory
Amino acids
Miller and Urey showed that organic compounds, including (nucleic acids) and sugars, could be formed in the laboratory just as predicted
Origin of life
This life in a test tube experiment of Millers and Urey provides support for some modern hypothesis of (biogensis)
Sidney Fox took Miler and Ureys experiment further and showed how amino acids could cluster to form (protocells)
Prokaryotic, anaerobic, heterotrophs
What was the characteristics of the first organisms on earth
make own food, didint have to compete for food
What is an autotroph? What factors helped them thrived on earth
achaebacteria, libe in harsh environment, chemosynthetic
What present day organism may be similar to the first autotrphs? why?
Oxygen increased in atmosphere due to process of photosynthesis
what change in the earths atmosphere after the evolution of photosynthezing prokaryotes
Basic elements
Alexander Oparin , J. B. S. Haldane
1942 a Russian, _____ developed a theory to explain, in his view the origin of life on earth. in 1929 an English man____ developed basically the same idea of how life began on earth
Ammonia, water vapor, lightning, rain falls to earth, soup, bacteria

Recombination occurs, replication occurs, 1st cells were formed

Heterotrophic, anaerobic, mutation, autotrophs, prokaryotic cell, eukaryotic, mitochondria

-compounds in the air are ____ methane, H2, ____+____>new substances in the form of ions>ions recombine to form new organic complex molecules>_____> organic soup pools are formed on earths surface>____increased molecules reactions>more complex molecules are formed which became the first living cells, prokaryotes. Think were similar to present day ____>
-Miller tested Oparins theory in lab, reproduced Oparins ideas, found organic soup, had two know amino acids, alanine and glycine>_____>molecules similar to DNA is formed>____>_____>
-First cells were similar to bacteria, cells were ____ and___> reproduced, have plenty of food and space in the organic soup pools on earths surface>large numbers of cells are now present. Therefore, there is a lot of competition for food. This may have lead to adaptation, maybe even ____>_____appeared and carried on process of chemsynthesis. some cells eventually carrying on photosynthesis, which insures better survival and increase in reproduction due to presence of O2 and usage of CO2 these photosynthetic cells were probably like our blue green algae___> Now there is a balance of heterotrophic cells and autotrophic cells these environments, pools of water on the surface of the earth is in a homeostatic situation>both kinds of cells mingle and form colonies the cells in the colonies help to support each other by providing food and O2>____cells were formed_____developed from aerobic bacteria which appeared after O2 was released into the atmosphere chloroplast developed from blue green algae
occurrence of first cells
1992 Sidney Fox heated solutions of amino acids, made protocells-can divide and grow
complex eukaryotic cells
____develop from prokaryotic cells
Endosymbiont theory
1960 Lynn Margul’s, prokaryotic cells ingested aerobic bacteria>mitochondria
Prokaryotic cells ingested bacteria having chlorophyll>chloroplast
Mitochondria and chloroplast have own DNA and can divide
the history of life worksheet

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