AP Biology Chapter 25 Flashcards

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Questions and Answers

Which of the following are included in the macro evolutionary changes shown by the fossil record? (Select all that apply)

Long-term impacts of mass extinctions (correct)

The development of mammals

The origin of photosynthesis (correct)

The emergence of terrestrial vertebrates (correct)

Which of the following are stages in the production of very simple cells on early Earth? (Select all that apply)

Formation of complex human cells

Joining of these small molecules into macromolecules (correct)

Packaging of molecules into 'protobionts' (correct)

Abiotic synthesis of small organic molecules (correct)

When did Earth form?

4.6 billion years ago

What did Earth's early atmosphere likely contain?

Water vapor and chemicals released by volcanic eruptions Signup and view all the answers

What did A.I. Oparin and J.B.S. Haldane hypothesize about the early atmosphere?

It was a reducing environment with no oxygen Signup and view all the answers

What did the experiments by Stanley Miller and Harold Urey demonstrate?

The abiotic synthesis of organic molecules in a reducing atmosphere is possible Signup and view all the answers

Where may the first organic compounds have been synthesized?

Near submerged volcanoes and deep sea vents Signup and view all the answers

What does the theory of panspermia suggest?

Amino acids have been found in meteorites Signup and view all the answers

What are the key properties of life?

Replication and metabolism Signup and view all the answers

What are protobionts?

Aggregates of abiotically produced molecules surrounded by a membrane or membrane-like structure Signup and view all the answers

What do protobionts exhibit?

Simple reproduction and metabolism and maintain an internal chemical environment Signup and view all the answers

What does the fossil record reveal?

Changes in the history of life Signup and view all the answers

What are sedimentary rocks?

Deposited into layers called strata and are the richest source of fossils Signup and view all the answers

What do strata represent?

Layers of sediment, the richest source of fossils Signup and view all the answers

What characteristics make species favored in the fossil record? (Select all that apply)

Had hard parts Signup and view all the answers

What do sedimentary strata reveal?

Relative ages of fossils Signup and view all the answers

What is radiometric dating?

A method to determine absolute ages of fossils Signup and view all the answers

What is a half-life?

The time it requires for half the parent isotope to decay Signup and view all the answers

What can radiocarbon dating be used to date?

Fossils up to 75,000 years old Signup and view all the answers

What can the magnetism of rocks provide?

Dating information Signup and view all the answers

What do reversals of the magnetic poles leave?

Their record on rocks throughout the world Signup and view all the answers

What are tetrapods?

A group of animals that mammals belong to Signup and view all the answers

How is the geological record divided?

Into the Achaean, Proterozoic, and Phanerozoic eons Signup and view all the answers

What does the Phanerozoic encompass?

Multicellular life Signup and view all the answers

What are the three eras of the Phanerozoic?

Paleozoic, Mesozoic, and Cenozoic Signup and view all the answers

What do major boundaries between geological divisions correspond to?

Extinction events in the fossil record Signup and view all the answers

What are the oldest known fossils?

Stromatolites Signup and view all the answers

How long were prokaryotes Earth's sole inhabitants?

From 3.5 to about 2.1 billion years ago Signup and view all the answers

Which of the following statements about oxygen is true? (Select all that apply)

Most atmospheric oxygen is of biological origin Signup and view all the answers

What is the Oxygen Revolution?

About 2.7 billion years ago, O2 began to accumulate Signup and view all the answers

When did the oldest eukaryotic cells appear?

2.1 billion years ago Signup and view all the answers

What does the hypothesis of endosymbiosis propose?

Mitochondria and plastids were formerly small prokaryotes living within larger host cells Signup and view all the answers

What is key evidence supporting an endosymbiotic origin of mitochondria and plastids? (Select all that apply)

Division is similar in these organelles and some prokaryotes Signup and view all the answers

What occurred during the second wave of diversification?

Multicellularity evolved and gave rise to algae, plants, fungi, and animals Signup and view all the answers

What does the 'snowball Earth' hypothesis suggest?

Periods of extreme glaciation confined life to the equatorial region or deep-sea vents Signup and view all the answers

What does the Cambrian Explosion refer to?

The sudden appearance of fossils resembling modern phyla in the Cambrian period Signup and view all the answers

When did fungi, plants, and animals begin to colonize land?

About 500 million years ago Signup and view all the answers

When did plants and fungi likely colonize land together?

By 420 million years ago Signup and view all the answers

What are arthropods and tetrapods?

The most widespread and diverse land animals Signup and view all the answers

How many times have Earth's land masses formed a supercontinent?

Three times Signup and view all the answers

What happens to Earth's crust? (Select all that apply)

Oceanic and continental plates can collide, separate, or slide past each other Signup and view all the answers

What were the effects of the supercontinent Pangaea?

Reduced shallow water habitat, colder and drier climate inland, changes in climate, and ocean circulation Signup and view all the answers

What did the breakup of Pangaea lead to?

Allopatric speciation Signup and view all the answers

Which statements about fossils are true? (Select all that apply)

The distribution of fossils reflects the movement of continental drift Signup and view all the answers

What does the Permian extinction define?

The boundary between the Paleozoic and Mesozoic eras Signup and view all the answers

What did the Cretaceous mass extinction result in?

Extinction of about half of all marine species and many terrestrial plants and animals Signup and view all the answers

What does the presence of iridium in sedimentary rocks suggest?

A meteorite impact about 65 million years ago Signup and view all the answers

How much higher is the current rate of extinction compared to the typical background rate?

100 to 1000 times Signup and view all the answers

What can mass extinction pave the way for?

Adaptive radiations Signup and view all the answers

What is adaptive radiation?

The evolution of diversely adapted species from a common ancestor upon introduction to new niches Signup and view all the answers

Study Notes

Fossil Record and Macro Evolution

Fossil record indicates significant macroevolutionary changes, including terrestrial vertebrates' emergence, the origin of photosynthesis, and long-term mass extinction impacts.
Sedimentary rocks, formed in strata, serve as the richest fossil source, revealing changes over time.

Early Earth and Life Formation

Earth originated approximately 4.6 billion years ago, developing a primordial atmosphere rich in water vapor and volcanic chemicals like nitrogen and methane.
A.I. Oparin and J.B.S. Haldane proposed that the early atmosphere lacked oxygen, creating a reducing environment conducive to life.
Experiments by Stanley Miller and Harold Urey demonstrated that organic molecules could be synthesized abiotically in such an atmosphere.

Evolution of Organic Compounds

Initial organic compounds may have originated near underwater volcanoes and deep-sea vents, rather than in the atmosphere.
The Panspermia theory supports the idea that life could have extraterrestrial origins, evidenced by amino acids found in meteorites.

Characteristics and Evolution of Life

Key properties of life include replication and metabolism, critical for the development of protobionts, which are aggregates of molecules enclosed in a membrane-like structure.
Protobionts demonstrated simple reproduction and metabolism, maintaining an internal chemical environment.

Geological Timeline and Eons

The geological record is divided into Achaean, Proterozoic, and Phanerozoic eons, with the Phanerozoic encompassing multicellular life.
The Phanerozoic is further segmented into Paleozoic, Mesozoic, and Cenozoic eras, with significant extinction events marking boundaries.

Evolutionary Milestones

The oldest fossils, stromatolites, indicate life existed 3.5 billion years ago, primarily consisting of prokaryotes until about 2.1 billion years ago.
The Oxygen Revolution, beginning around 2.7 billion years ago, marked an increase in atmospheric oxygen due to cyanobacteria, enabling new energy sources and diverse ecosystems.

Eukaryotic Evolution

The oldest eukaryotic cells date back to 2.1 billion years. The endosymbiotic hypothesis posits that mitochondria and plastids originated from prokaryotes living within host cells, supported by structural and functional similarities.

Cambrian Explosion and Land Colonization

The Cambrian Explosion (535 to 525 million years ago) witnessed the rapid appearance of fossils resembling modern phyla.
Fungi, plants, and animals began terrestrial colonization around 500 million years ago, likely in concert, with evidence of joint colonization by plants and fungi by 420 million years ago.

Continental Drift and Supercontinents

Earth's continents shift gradually due to continental drift, influencing geological formations, climate, and ecosystems.
Pangaea, the last supercontinent, formed about 250 million years ago, altering shallow water habitats and overall climate, and later fragmented, leading to allopatric speciation.

Mass Extinctions and Their Consequences

The Permian extinction event (~252 million years ago) was catastrophic, killing approximately 96% of marine species.
The Cretaceous mass extinction (65.5 million years ago) led to the demise of many species, including dinosaurs, likely due to a meteorite impact, with sedimentary evidence of iridium confirming this hypothesis.
Current extinction rates are alarming, estimated to be 100 to 1000 times the background rate, indicating a potential mass extinction and subsequent adaptive radiations in the future.

Adaptive Radiation

Adaptive radiation describes the evolution of diverse species from a common ancestor, particularly after environmental changes or the introduction of new niches.

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Explore the fascinating history of life on Earth through these flashcards covering key concepts in AP Biology Chapter 25. From the emergence of terrestrial vertebrates to the origins of photosynthesis, test your knowledge on macroevolutionary changes and early cellular processes. Perfect for study and revision!