BIOLOGY CHAPTER 15
Origin of Single-Celled Eukaryotes (dates back 1.8 billion years ago): Origin of Multicellular Eukaryotes (dates back 1.2 billion years ago): A great increase in the diversity of animal forms occurred 535-525 million years ago, during a span of time known as the __________ explosion
Cambrian
3) What is the point of the condenser? 4) As materials cycled back to the sea, Miller collected samples for chemical analysis
Cold water circulates so it cools the atmosphere, raining water and any other compounds back into the sea
What types of animals went through mass extinction at the end of the Paleozoic era?
MARINE and TERRESTRIAL organisms
Evolutionary changes above the species level are referred to as ________
Macroevolution
Even though Phanerozoic is the shortest eon (only the last 541 million years), the eon is divided into three ERAS, and the eras are subdivided into periods Boundaries between ERAS are marked by _____ Lesser extinctions often mark the boundaries between ______
Mass extinction Periods
Enzymes catalyze the joining of monomers to build POLYMERS. How can this happen WITHOUT enzymes?
Monomers are dropped onto hot sand,clay, rock and the heat VAPORIZES the water and concentrates the monomers and some of the them bond together in chains ---> polymers Early Earth: Waves splash organic monomers onto lava or hot rock then brings polymers back into the sea
4) The origin of self-____ molecules that eventually makes inheritance possible
Replicating
The method that is most often used to determine the ages of rocks/fossils is called radiometric dating. What is radiometric dating based on?
The decay of radioactive isotopes into stable isotopes at a rate that can be measured.
What would a scientist change in Miller's apparatus to incorporate new evidence about Earth's early atmosphere?
The mixture of gases in the second flask
Colonization of Land by larger forms of life (dates back 500 million years ago) For how long did life on Earth consist solely of single-celled organisms?
almost 2.3 billion years
Phanerozoic EON: Paleozoic "____ animal" era Mesozoic "____ animal" era Cenozoic "____ animal" era
ancient middle recent
Define Proteinoid microspheres - have many characteristics of living cells Semi-permeable membrane, Able to store and release energy
bubbles given off from organic molecules
Fossils contain isotopes of elements that accumulated when the organisms were alive. When an organism dies, its carbon-14 starts to decay to another element. The rate of decay is expressed as a _____, the time required for 50% of the isotope in a sample to decay
half life
Earth's history is divided into 4 eons, what are they?
1. Hadean 2. Archaean 3. Proterozoic 4. Phanerozoic
Earth and its atmosphere are made up of INorganic molecules but organic molecules are essential to the structures and functions of life. Why does present-day conditions on Earth not allow the spontaneous synthesis of organic compounds and how did the first organic molecules arise in the early atmosphere?
1920s: Oparin and Haldane hypothesis Present day atmosphere is rich in OXYGEN Before photosynthetic prokaryotes added OXYGEN to the air, organic molecules was created by abiotic synthesis with the energy from lightning and intense UV Radiation
1) RNA monomers stick to clay particles and become concentrated 2) Some monomers spontaneously join, which form the first small _____ 3) Then an RNA Chain complementary to one of these genes assembles. If the new chain, IN TURN, serves as a template for another round of RNA assembly, what results?
2) genes 3) A replica of the ORIGINAL gene
What is the half life of carbon-14
5730 years
How did life arise? Scientists hypothesize that chemical and physical processes on early Earth could have produced very simple cells FOUR MAIN STAGES 1) The abiotic (nonliving) synthesis of small organic molecules, such as _____
Amino acids and Nitrogenous bases
By the end of the Mesozoic, dinosaurs had went through mass extinction except for one lineage - the ___
BIRDS
The Mesozoic era: known as the age of REPTILES because of its abundance of reptilian fossils, including those of _____
Dinosaurs
Earth formed about 4.6 billion years ago from gases, dust, and rocks that collided and stuck together while swirling around the SUN Impact of meteorites and compaction by gravity generated immense heat and Earth started off as a molten mass that sorted into LAYERS of varying densities. The least dense material on the SURFACE became the thin crust
FIRST atmosphere: thick with water vapor and other compounds released by volcanic eruptions As Earth gradually COOLED, water vapor ----> oceans
What is the earliest evidence of life on Earth that are about 3.5 billion years old?
Fossils
Scientists use the term "RNA world" for the hypothetical period in the evolution of life when RNA served as both rudimentary _____ and catalytic molecules
Genes
Based on the fossil record, sequence and the ages of rocks/fossils, geologists have established the ____ record of Earth's HISTORY
Geologic
2) Water vapor moved up to "Earth's atmosphere" and what are the 3 other gases there that scientists thought prevailed in the ancient world? Electrodes discharged sparks into the flask (circle) to mimic _____
Hydrogen Gas (H2) Methane (CH4) Ammonia (NH3) Lightning
Why do 3.5 billion year old stromatolites suggest that life originated before 3.5 billion years ago?
If photosynthetic prokaryotes existed by 3.5 billion years ago, a SIMPLER, NON-photosynthetic cell probably originated well before that time
Origin of Prokaryotes (dates back 3.5 billion years ago): Transformations of energy and matter by prokaryotes had a lasting impact on the biosphere What important gas appeared in the atmosphere as a result of prokaryotic photosynthesis
Oxygen
First forms of life were protocells that become _____ cells
Prokaryotic
2) The joining of these small molecules into polymers, such as _______
Protein and Nucleic Acids
Define Ribozymes
RNA molecules capable of acting as an enzyme
Until well into the 1800s, people commonly believed that nonliving matter could generate living organisms randomly ex) flies from rotting meat, fish from ocean mud 1862: Experiments by French scientist Louis Pasteur proved otherwise Confirmed that all life arises ONLY by the ________
Reproduction or PREexisting life
1953: Stanley Miller TESTED the Oparin-Haldane hypothesis MILLER-UREY EXPERIMENT 1) Why was the water (H2O) heated? What does water become when heated? And what does the H2O represent?
So that the water could vaporize and move up Represented the SEA
Ancient layered "stepping stones"/rocks constructed by ancient photosynthetic prokaryotic cells are referred to as ______
Stromatolites (also date back 3.5 billion years)
3) The packaging of these molecules into "____", droplets with membranes that maintained an internal chemistry different from that of their surroundings
protocells Prefix proto-: first, example
