Week 5: Evidence in Evolutionary Biology (guest lecture) Flashcards
what are the two necessary elements for macroevolution
Genetic heritability
Deep time
describe Genetic heritability
Passing characteristic features from parent to offspring, biological inheritance
define “fit” as it pertains to evolution
characteristics that allow you to reproduce
what are the two parts of “deep time” that assess passage of time
Relative dating: putting events in order
Absolute dating: applying a time “stamp”
what is Stratigraphy
branch of geology that focuses on the study of rock layers (strata) and their arrangement in the Earth’s crust.
what are the 3 different types of rock
Igneous Rocks:
Formation: Igneous rocks form from the cooling and solidification of molten material called magma
Sedimentary Rocks:
Formation: Sedimentary rocks are formed through the accumulation and consolidation of sediments, which can be mineral grains, organic material, or chemical precipitates.
Metamorphic Rocks:
Formation: Metamorphic rocks are formed from pre-existing rocks (either igneous, sedimentary, or other metamorphic rocks) that undergo significant changes in temperature, pressure, or mineral composition
how do fossils form
Mineralization or Petrification: In this process, the organic material of an organism’s body, such as bones, shells, or wood, is gradually replaced by minerals. It occurs when an organism is buried by sediments, such as sand or mud, that gradually replace the original organic material, preserving the organism’s structure in stone.
what is the Principle of Superposition
The Principle of Superposition is a fundamental concept in the field of stratigraphy, a branch of geology that deals with the study of rock layers and their chronological order.
The principle states that in an undisturbed sequence of sedimentary rocks or layers, the youngest rocks are at the top, and the oldest rocks are at the bottom.
How do fossils and the Principle of Superposition permit relative dating?
Principle of Superposition: This principle states that in an undisturbed sequence of sedimentary rocks, the youngest rocks are found at the top, while the oldest rocks are at the bottom. The Principle of Superposition provides a relative chronological order for sedimentary rock layers. It’s a fundamental concept in stratigraphy, helping geologists understand the sequence of events that occurred over time.
Fossils: Fossils are the preserved remains or traces of once-living organisms. They can include the remains of plants, animals, and even microorganisms. Fossils are critical in relative dating because different organisms existed at different times in Earth’s history. Some organisms only lived during specific geological time periods, and this information is used to create a framework for relative dating.
By combining the information from the Principle of Superposition and the presence of specific fossils or fossil assemblages, geologists can create a relative chronological framework for a sequence of sedimentary rock layers. This allows them to understand the order of events, such as the deposition of sediments and the existence of different life forms, without assigning specific numerical ages.
what is Radiometric dating
a method used to determine the absolute age of rocks and minerals
Unlike relative dating methods, which establish the chronological order of events but not their actual ages, radiometric dating provides numerical age estimates in years. It relies on the principles of radioactive decay.
how does radiometric dating work
Radioactive Isotopes: are unstable forms of elements. These isotopes undergo a process called radioactive decay, during which they transform into stable daughter isotopes over time. This decay occurs at a predictable and constant rate, which is characteristic of each radioisotope.
Half-Life: Each radioactive isotope has a specific half-life, which is the time it takes for half of a sample of the isotope to decay into its daughter isotope. The half-life is a fundamental property of the radioisotope and does not change.
Accumulation of Daughter Isotopes: When a rock or mineral forms, it may contain a certain amount of a radioactive parent isotope. Over time, the parent isotope decays into the stable daughter isotope. By measuring the ratio of parent to daughter isotopes in a sample, scientists can determine how many half-lives have elapsed, which provides a way to calculate the age of the sample.
Measuring Isotope Ratios: Radiometric dating methods involve measuring the ratio of parent and daughter isotopes using specialized instruments like mass spectrometers. By comparing these ratios to the known half-life of the radioisotope, scientists can calculate the absolute age of the sample.
What can be dated
Only igneous materials that have allowed isotopes to be “locked in” since formation
what are the 5 Evidences for Evolution based on paleontology
- Branching organization of life
- Transitional fossils
- Homologous structures
- Vestigial structures
- Convergent evolution
what are Transitional fossils
Transitional fossils are a type of fossil that provides evidence of evolutionary transitions between different groups of organisms.
what are Homologous structures
Homologous structures are anatomical features or traits found in different species that share a common evolutionary origin or ancestry. These structures may have evolved to serve different functions in various species, but their similarity in terms of structure, development, or origin suggests a common ancestor.
