Podcast
Questions and Answers
When were the first fossils of life dated to?
When were the first fossils of life dated to?
about 3.5 billion years ago (bya)
When was Earth formed?
When was Earth formed?
4.6 bya
When did it calm and the oceans start to form?
When did it calm and the oceans start to form?
about 3.9 bya
What are the four parts of the four-part hypothesis and what is it?
What are the four parts of the four-part hypothesis and what is it?
How was the Earth's early atmosphere different chemically than today and what were the main energy sources in it?
How was the Earth's early atmosphere different chemically than today and what were the main energy sources in it?
Who performed the abiogenesis experiment and what was it called?
Who performed the abiogenesis experiment and what was it called?
How were early monomers facilitated in their transformation into polymers?
How were early monomers facilitated in their transformation into polymers?
What three advancements did Protobionts bring?
What three advancements did Protobionts bring?
Name for RNA with enzymatic activity.
Name for RNA with enzymatic activity.
What is the main advantage of RNA developing?
What is the main advantage of RNA developing?
What are three constraints on the fossil record?
What are three constraints on the fossil record?
What are the two most common isotopes used for radiometric dating and their half-lives?
What are the two most common isotopes used for radiometric dating and their half-lives?
When was the time span of the first fossil evidence and what were the organisms found?
When was the time span of the first fossil evidence and what were the organisms found?
Where did photosynthesis start?
Where did photosynthesis start?
When did oxygen build up in the oceans start?
When did oxygen build up in the oceans start?
What was the main influencing factor in increasing diversification?
What was the main influencing factor in increasing diversification?
When were the first Eukaryotic fossils found?
When were the first Eukaryotic fossils found?
What kind of relationship did early Eukaryotes often have with prokaryotes and what two organelles were the result of this?
What kind of relationship did early Eukaryotes often have with prokaryotes and what two organelles were the result of this?
When were the first fossils of Multicellular Eukaryotes found?
When were the first fossils of Multicellular Eukaryotes found?
The oldest complex animal fossils were found about?
The oldest complex animal fossils were found about?
What was the incredible diversification of animals called and when did it occur?
What was the incredible diversification of animals called and when did it occur?
What three major events occurred in the Cambrian explosion concerning the classification of species?
What three major events occurred in the Cambrian explosion concerning the classification of species?
What were the first organisms to make it to land?
What were the first organisms to make it to land?
How many times has Earth had a super-continent?
How many times has Earth had a super-continent?
How many major mass extinctions were there and what is this group of events referred to as?
How many major mass extinctions were there and what is this group of events referred to as?
What is the most famous of these events and what is it called?
What is the most famous of these events and what is it called?
What does Kreiser believe about extinction events?
What does Kreiser believe about extinction events?
Who were the creators of the primitive soup model?
Who were the creators of the primitive soup model?
What was the primitive soup model?
What was the primitive soup model?
Should monomers be able to link without the assistance of cells and enzymes?
Should monomers be able to link without the assistance of cells and enzymes?
What did protobionts do and was it a biotic process?
What did protobionts do and was it a biotic process?
What was probably the first genetic material?
What was probably the first genetic material?
What was the first fossil evidence?
What was the first fossil evidence?
Origin of prokaryotes?
Origin of prokaryotes?
Where did photosynthesis start?
Where did photosynthesis start?
When did oxygen start to build up in the oceans?
When did oxygen start to build up in the oceans?
What are the good and bad effects of O2 increase?
What are the good and bad effects of O2 increase?
When were the first fossils of Eukaryotic life found?
When were the first fossils of Eukaryotic life found?
What was the incredible diversification of animals most noted in this course and when did it occur?
What was the incredible diversification of animals most noted in this course and when did it occur?
What occurred during the Cambrian explosion?
What occurred during the Cambrian explosion?
What does molecular data point to about the appearance of phyla in the Cambrian explosion?
What does molecular data point to about the appearance of phyla in the Cambrian explosion?
How many times has Earth been in a supercontinent?
How many times has Earth been in a supercontinent?
How many major mass extinction events were there and what are they referred to as?
How many major mass extinction events were there and what are they referred to as?
Which was the asteroid and how big was it?
Which was the asteroid and how big was it?
What are the names of the first two eons and their time span?
What are the names of the first two eons and their time span?
What is the name of the current eon and its time span?
What is the name of the current eon and its time span?
What is the origin of life and what specific structure of organisms?
What is the origin of life and what specific structure of organisms?
When did multicellular life appear on land?
When did multicellular life appear on land?
What is a classic example of speciation by isolation?
What is a classic example of speciation by isolation?
What are the extrinsic drives of changes in body plans? (name 3)
What are the extrinsic drives of changes in body plans? (name 3)
What is the term for changes in rate/timing of gene expression and give an example of this?
What is the term for changes in rate/timing of gene expression and give an example of this?
What do developmental genes control? (name 3 things)
What do developmental genes control? (name 3 things)
What is the term for the early development of reproductive systems or retention of juvenile characteristics and give an example?
What is the term for the early development of reproductive systems or retention of juvenile characteristics and give an example?
What are homeotic genes? Give an example.
What are homeotic genes? Give an example.
Is evolution goal oriented?
Is evolution goal oriented?
What is the term for traits that evolved in one context that may assume a new role?
What is the term for traits that evolved in one context that may assume a new role?
Study Notes
Fossils and Earth's Formation
- First fossils of life dated to approximately 3.5 billion years ago.
- Earth formed around 4.6 billion years ago.
- Conditions stabilized and oceans began to form about 3.9 billion years ago.
Formation of Life Hypothesis
- The four-part hypothesis explaining life's origins includes:
- Abiotic synthesis of small organic molecules.
- Formation of polymers from these molecules.
- Emergence of protobionts with membranes.
- Development of self-replicating molecules (RNA).
Early Earth's Atmosphere
- The early atmosphere was more reduced compared to today.
- Main energy sources included ultraviolet radiation and lightning.
Abiogenesis Experiment
- Conducted by Miller and Urey in 1953, using a spark discharge chamber to simulate organic synthesis.
Transformation of Early Monomers
- Clay matrices played a critical role in facilitating the transformation of monomers into polymers.
Advancements by Protobionts
- Protobionts encapsulated polymers in membranes.
- Achieved simple reproduction through liposomes.
- Possessed rudimentary metabolism.
RNA and Self-Replication
- Ribozymes, RNA molecules with enzymatic activity, emerged as crucial players in early life.
- The primary advantage of RNA is its ability to self-replicate.
Fossil Record Constraints
- The fossil record is limited by time, place, and organism diversity.
Radiometric Dating Isotopes
- Carbon-14 (C14) with a half-life of approximately 5,730 years.
- Uranium-238 (U238) with a half-life of about 4.5 billion years.
Prokaryotes and Photosynthesis
- First fossil evidence of prokaryotes found between 3.5 and 2 billion years ago.
- Photosynthesis began in prokaryotes, specifically cyanobacteria, leading to significant changes in Earth's atmosphere.
Oxygen and Diversification
- Oxygen accumulation in oceans started around 2.7 billion years ago.
- Increased O2 levels greatly influenced the diversification of life.
Eukaryotic Life
- First eukaryotic fossils dated to about 2.1 billion years ago.
- Often exhibited an endosymbiotic relationship with prokaryotes, leading to the formation of chloroplasts and mitochondria.
Multicellular Eukaryotes
- First fossils of multicellular eukaryotes found around 1.2 billion years ago.
- Complex animal fossils appeared approximately 575 million years ago.
Cambrian Explosion
- Significant diversification of animals known as the Cambrian explosion occurred around 550 million years ago.
- Characterized by the appearance of most major animal phyla and well-defined body plans.
Land Colonization
- Bacteria were the first organisms to inhabit land.
Super-Continents
- Earth has experienced three super-continent formations throughout its history.
Mass Extinctions
- Five major mass extinctions, collectively referred to as the "Big 5."
- The most famous extinction event is the K-T extinction, caused by a 10 km asteroid impact.
Current Perspectives
- Kreiser posits that current human activities may be instigating another extinction event.
Primitive Soup Model
- Proposed by Oparin and Haldane, suggesting organic compounds could form from inorganic precursors in a primordial environment.
Genetic Material and Abiotic Processes
- RNA likely served as the first genetic material.
- Protobionts emerged via abiotic processes that produced membrane-bound molecules.
Evolutionary Concepts
- Heterochrony describes changes in gene expression timing, exemplified by skull shape differences between chimpanzees and humans.
- Paedomorphosis represents early development of reproductive systems, illustrated by species like the axolotl.
Homeotic Genes and Evolution
- Homeotic genes, including Hox genes, play a role in genetic duplication and divergence, influencing major body plan development.
- Evolution is NOT goal-oriented but rather a response to environmental pressures and changes.
Exaptation
- Exaptation refers to traits that evolve for one purpose and later adapt to a different role, showcasing the adaptability of organisms.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz covers essential concepts from Chapter 25, focusing on the history of life on Earth. Test your knowledge on the timeline of Earth's formation and the emergence of life through a series of flashcards. Perfect for students looking to reinforce their understanding of geological time and biological evolution.
