lectrure 3- evidence of evolution Flashcards
(44 cards)
what are the 2 definitions of theory regarding science?
Theory (1): A hypothesis propose as an explanation; hence a speculation, conjecture; an idea or set of ideas about something; and individual view or notion.
Theory (2): A scheme or system of ideas or statements held as an explanation or accounts of a group or facts or phenomena;a hypothesis that has been confirmed or established by observation or experiments and is propounded or accepted as accounting for the known facts; a statement of what are held the general laws, principle, or causes of something known as observed
what is a theory in science? and what are some theories?
“A hypothesis that has been confirmed or established by observation or experiments and is propounded or accepted as accounting for the known facts (…)”
Heliocentric theory
Gravitational theory (Newton’s Law of Gravity)
Big Bang Theory
Cell theory
Theory of plate tectonics
Theory of Evolution
define domestication
Domestication refers to the process by which wild animals or plants are selectively bred and managed by humans for specific purposes, leading to changes in their genetics, behavior, and morphology. It involves the adaptation of wild species to live and reproduce in human-controlled environments, such as farms, households, or other managed settings. Domestication typically results in traits that are desirable to humans, such as increased docility, productivity, or nutritional value.
define artificial selection
Artificial selection, also known as selective breeding or human-directed evolution, is a process by which humans intentionally select and breed organisms with desired traits to produce offspring with those same traits. This process mimics the natural selection mechanism observed in the wild but is directed by human preferences or goals rather than natural environmental pressures
who breeds in natural selection?
In natural selection you don’t need a breeder, you don’t need a selector, survival will do it for you
what is macro evolution?
It refers to larger changes over a long-time scale.
what is the path to macro evolution showing us for certain fish?
*That fishing rod has been shaped by selection by the eyes of generations of prey fish
*The ones that look most like wriggling worms, were most successful in luring prey
what does survival determine for natural selection?
Survival is all it takes to determine the non-random survival of genes that made the desirable characteristic
As the generations go by, the number of genes that are successful in building bodies that are good at surviving, are the ones that we see in gene pools in species all over the world.
what are some different forms of evidence for evolution?
Anatomy: Species may share similar physical features because the feature was present in a common ancestor
Fossils: They document the existence of now-extinct past species that are related to present-day species
Natural history: Traits present in organisms can be understood only in view of their evolutionary path
Embryology: Traits present in organisms can be understood only in view of their evolutionary path
Biogeography: The global distribution of organisms reflects evolution and geological change
how does anatomy relate to proof of evolution?
Organisms often look similar in their morphology
what is homology? what does it show?
the relatedness of life forms
two traits that have descended from a common ancestral character
such as the wings of a bat, arms of a human, legs of a cheetah or fins of a what having the same bones
what is homology and analogy?
Homology= the relationship of any two traits that have descended from a common ancestral trait
Analogy= The relationship of any two traits that have descended from “unrelated” ancestors through convergent evolution
Homologous structures provide evidence for common ancestry
what is a fossil? and what are the different types?
A fossil is the preserved remains of a once-living organism.
Petrified Fossils
Molds and Casts
Carbon Films
Trace Fossils
Preserved Remains
what do Fossil records show us?
Fossils in older layers are more primitive than those in the upper layers
*Most recent fossils more resemble extant species
*Species change over time
*Transitional forms in major groups *Variation within each species
*Cases of imperfect adaptation
what is the Principle of superposition
These early geologists simply ordered the different layers of rocks that they found
Deeper layers must have been laid down before the shallower ones
Use fossils to cross-correlate different locations
how do we determine a fossil’s age?
Fossils are generally only found in sedimentary rocks
We can calculate the date of formation of the igneous rock, using radioactive isotopes decay
what are the half-lives of important elements?
Element Half-life
Uranium-4.5 Billion years
Californium- 800 years
neptunium- 1hour
Plutonium- 5 hours
Americium- 25 minutes
Nobelium- 3 seconds
Carbon- 5730 years
Carbon-740 milliseconds
how old is the planet?
The planet is 4.6 billion years old
order the different periods of evolution
1- archean
2- proterozoic
3- paleozoic
4- Mesozoic
5- Cenozoic (with humans)
what is the missing link of fossil evolution?
The concept of a “missing link” in fossil evolution refers to a hypothetical transitional fossil that would fill a perceived gap in the fossil record between two different species or lineages. It’s important to note that this term is somewhat outdated and can be misleading, as it implies that there is a single fossil that is crucial for understanding evolutionary relationships. In reality, the fossil record is complex and incomplete, and our understanding of evolutionary relationships is based on a large body of evidence rather than a single fossil.
In paleontology and evolutionary biology, scientists use the term “transitional fossil” instead of “missing link.” Transitional fossils are fossils of organisms that display traits that are intermediate between those of their presumed ancestors and descendants. They provide valuable evidence for evolutionary transitions and the gradual change of species over time.
While there are certainly gaps in the fossil record, scientists have discovered numerous transitional fossils that provide insight into various evolutionary transitions, such as the evolution of whales from land-dwelling ancestors, the evolution of birds from theropod dinosaurs, and the transition from fish to tetrapods (four-legged vertebrates).
It’s also worth noting that our understanding of evolution is not solely based on the fossil record. Other lines of evidence, such as comparative anatomy, embryology, genetics, and biogeography, contribute to our understanding of evolutionary relationships and processes. Overall, while there may not be a single “missing link” fossil, the cumulative evidence from multiple sources allows scientists to reconstruct the history of life on Earth and understand how different species are related to one another
what does Evidence from fossil record provide?
The fossil record provides valuable evidence for understanding the history of life on Earth and the processes of evolution. Here are some key contributions of the fossil record:
Documentation of Extinct Species: Fossils provide direct evidence of organisms that lived in the past but are now extinct. By studying these fossils, scientists can reconstruct the diversity of life forms that have inhabited the Earth throughout its history.
Transitional Forms: Fossils often preserve intermediate or transitional forms between different groups of organisms. These transitional fossils provide evidence for evolutionary transitions, such as the evolution of whales from land mammals, the evolution of birds from theropod dinosaurs, and the transition from fish to tetrapods (four-legged vertebrates).
Chronological Sequence: Fossils are dated based on the layers of rock in which they are found, allowing scientists to establish a chronological sequence of life forms over time. This chronological sequence helps researchers understand the timing and pace of evolutionary events and the order in which different groups of organisms appeared and diversified.
Biogeographic Patterns: Fossils found in different regions of the world provide information about past geographic distributions of species and changes in Earth’s continents and environments over time. This evidence helps scientists reconstruct past environments and understand how organisms have migrated and adapted to changing conditions.
Evidence of Extinction Events: Mass extinctions, such as the one that marked the end of the Cretaceous period and the extinction of non-avian dinosaurs, are documented in the fossil record. Studying these extinction events can provide insights into their causes and consequences and help predict future patterns of extinction in response to environmental changes.
Evolutionary Trends: Fossils reveal patterns of evolutionary change over long periods of time, such as trends in body size, shape, and complexity. By studying these trends, scientists can infer the processes driving evolutionary change and the selective pressures that have shaped the diversity of life on Earth.
what can we learn about evolution regarding the whale?
Evolution of snout-blowhole
The evidence for the evolution of whales from land-dwelling ancestors comes from a combination of:*fossil evidence, *comparative anatomy, *and genetic studies
What do fossils teach us?
Confirm several predictions of evolutionary theory:
*gradual change within lineages *splitting of lineages
*the existence of transitional form
We find transitional forms in the fossil record precisely where they should be
Evolutionary change, even of a major sort, always involves remodelling the old into the new
legs of land animals ➔limbs of ancestral fish
Mammal’s middle ear bones➔jawbones of reptilian ancestors
Birds’ wings ➔the forelegs of dinosaurs
does natural selection occur with new material?
no
Natural selection can act only by changing what already exists
New species will be modified versions of older ones
