Chapter 12- The History Of Life Flashcards
Occurs when minerals carried away by water are deposited around a hard structure. They may also replace the hard structure itself.
Permineralization
Form when flowing water removes all of the original bone or tissue, leaving just an impression in sediment. Minerals fill in the mold, recreating the original shape of the organism.
Natural casts
Records the activity of an organism
Ex. Nests, burrows, imprints of leaves, and footprints
Trace fossils
Organisms that become trapped in tree resin that hardens into Amber after the tree gets buried underground.
Amber preserved fossils
Form when an entire organism becomes encased in material such as ice or volcanic ash or immersed in bogs.
Preserved remains
Most fossils form in what kind of rock?
Sedimentary
What is the best kind of environment for fossilization?
Wetlands, bogs,many areas where sediment is continuously deposited
Where do most fossils result from?
Permineralization
Estimates the time during which an organism loved by comparing the placement of fossils of that organism with the placement of fossils in other rock layers
Relative dating
A technique that uses the natural decay rate of unstable isotopes found in materials in order to calculate the age of the material
Radio metric dating
Atoms of an element with the same number of protons but a different number of neutrons
Isotopes
The amount of time it takes for half of the nuclei isotope in a sample to decay into a different element or its product isotope
Half life
What isotope is commonly used for radioactive dating?
14^C
Fossils of organisms that existed only during specific spans of time over large geographic areas
Index fossils
What determines the age of fossils or strata they’re found in?
Index fossils
What are the best index fossils to use?
Most common, easiest to indent icy, found widely around the world, and only existed for a brief amount of time
A representation of the history of Earth and organizes Earth’s history by major changes or events that have occurred using evidence from the fossil/ geologic records
Geologic time scale
Last tens to hundreds of millions of years and consist of two or more periods
Eras
The most commonly used unit of time on the geologic scale, lasting tens of millions of years. Each are associated with a particular type of rock system.
Period
The smallest unit of geologic time and lasts several million years
Epochs
Ancient life era
Paleozoic
Middle life era
Mesozoic
Recent life era
Cenozoic
A cloud of gas/ dust in space
Nebula
What is the most widely accepted hypothesis of Earth’s origin?
Earth formed by a condensing nebula
What is the meteorite hypothesis?
Organic molecules may come to earth through meteorite or asteroid impacts
How could the behavior of lipids lead to the formation of the first cells?
Lipid molecules formed membranes which formed into spheres called liposomes.
What did the Miller-Urey demonstrate?
Organic molecules form from inorganic molecules beloved to be present in the early atmosphere.
When one organism lives inside the body of another, and both benefit the relationship
Endosymbiosis (or mutualism)
What theory states that larger prokaryotes took up smaller prokaryotes that became what?
Mitochondria and chloroplasts
The fossil evidence indicates that anaerobic prokaryotes were what?
The first living organisms
RNA molecules that can catalyze specific chemical reactions
Ribozymes
Bacteria that can carry out photosynthesis
Cyanobacteria
What is the proof that mitochondria and chloroplasts were once smaller prokaryotes?
- mitochondria and chloroplasts have their own DNA and chromosomes
- can copy themselves in their cells
- about the same size as prokaryotes
- DNA forms in circles
- gene structures are similar to prokaryotes
The evolution of primates is thought to have occurred in which of the following time periods?
Cenozoic era
Which periods make up the Mesozoic era?
Triassic, Jurassic,many Cretaceous
Which is the longest time span in Earth’s history?
Cenozoic era
What is called the age of the reptiles because dinosaurs lived at the time and also features flowering plants, birds, and the oldest direct mammal ancestor?
Mesozoic era
What periods is Cenozoic era divided into?
Tertiary and quaternary
Era of geologic time (544 to 248 million years ago) during which members of every maker animal group alive today evolved
Paleozoic
Era during which dinosaurs roamed the Earth (from 248 million years ago to 65 million years ago)
Mesozoic
Geologic time period that began 65 million years ago and continues today
Cenozoic
Earliest part of the Paleozoic era, when a huge diversity of animal species evolved
Cambrian explosion
What are the ways fossils can form?
Permineralization, natural casts, trace fossils, Amber preserved, and preserved remains
