Chapter 15 Evolution
Mass Extinction
An episode during which large numbers of species become extinct Currently going through next mass extinction because of humans (6th) 65 million years ago there was one believed to be caused by asteroid
Geologic Column
Arrangement of rock layers in which the oldest rocks are at the bottom. Geological column contains all the known fossils and rock formations on Earth arranged from oldest to youngest Comparing and piecing rock samples rom around world When unsure about a certain rock sequence, they use the geologic column
What are used to compare the relative ages of fossils
Index Fossils
Evaluating Lamarck's Hypotheses
Lamarck did not know: how traits are inherited. that an organism's behavior has no effect on its heritable characteristics. However, he paved the way for the work of later biologists.
Flaw of Lamarck
Lamarck proposed that by selective use or disuse of organs, organisms acquired or lost certain traits during their lifetime. These traits could then be passed on to their offspring. Over time, this process led to change in a species. Flaws: Tendency toward perfection Traits don't evolve to perfect Use and Disuse If you don't use it, you still have it (in contrary to Lamarck)
Malthus and his theories
Malthus reasoned that if the human population continued to grow unchecked, sooner or later there would be insufficient living space and food for everyone
Vestigial Features
Many organisms have features that seem to serve no useful function. These apparently useless features are said to be vestigial. Vestigial features were useful to an ancestor, but they are not useful to the modern organism that has them.
Inherited Variation and Artificial Selection
Members of each species vary from one another in important ways. Darwin noted that plant and animal breeders would breed only the largest hogs, the fastest horses, or the cows that produced the most milk. Darwin termed this process artificial selection. Artificial selection is the selection by humans for breeding of useful traits from the natural variation among different organisms.
Giraffes got long neck
NOT FROM Stretching, but from mutations, Theorized that there used to be short necked giraffes and low vegetation, eventually led to higher vegetation and long necked giraffes mated more while short necked always looked for food
Because of its similarities to artificial selection, Darwin referred to the survival of the fittest as
Natural Selection Over time, natural selection results in changes in the inherited characteristics of a population. These changes increase a species' fitness in its environment.
Peter and Rosemary Grant
Natural selection experiment with Finches, Dry year had tougher seeds and only big beak finches flourished Wet Year had smaller beak flourishing
Descent with modification.
Principle where natural selection produces organisms that have different structures, establish different niches, or occupy different habitats. Each living species has descended, with changes, from other species over time.
Natural Selection
Process by which organisms with favorable variations reproduce at higher rates than those without such variations. It is one of the major influencing factors in the process of evolution
On the Origin of Spcies
Proposed a mechanism for evolution, natural selection presented evidence that evolution has been taking place for millions of years—and continues in all living things.
Hutton
Realized that natural forces broke rock into smaller particles, and would deposit into sediment and reset cycle
Most fossils form in what rock
Sedimentary
Fossils are mostly in what rock
Sedimentary (many layers)
Homologous Features
Similar features that originated in a shared ancestor are described as homologous features.
Extant
Species that are still alive
Law of Superposition
States that a sedimentary rock layer is older than the layers above it and younger than layers below it
According to Lamarck
Thought that the parent's experience to their life would happen to the children (mouse tails) Lamarck recognized: Living things changed over time All Species were descended from other species Organisms were adapted to their environments
When has reproductive isolation occured
When the members of two populations cannot interbreed and produce fertile offspring,
Index Fossils
a species that is recognizable and that existed for a short period but had a wide geographic range.
Adaptation
any inherited characteristic that increases an organism's chance of survival.
Analogous Features
are structures in more than one organism that have similar appearance and function but different embryological origin.
Gradualism
biological change was slow and steady, made by Darwin
Natural Selection and chance events can
can change the relative frequencies of alleles in a population and lead to speciation.
Adaptive Radiation
is the process by which a single species or a small group of species evolves into several different forms that live in different ways. 14 finches from 1 finch All fill different niches, so they can coexist
Macroevolution
large-scale evolutionary patterns and processes that occur over long periods of time.
Geographic Isolation
occurs when two populations are separated by geographic barriers such as rivers or mountains.
Fossil Record
provides evidence about the history of life on Earth. It also shows how different groups of organisms, including species, have changed over time.
Hutton and Lyell
recognized Earth is millions of years old and the processes that changed Earth in past are same processes that operate in the present
Speciation
the formation of new species. A species is a group of organisms that breed with one another and produce fertile offspring.
Hox Genes
the master control genes of body layout.
Divergent Evolution
the process by which two or more related species become more and more dissimilar.
Convergent Evolution
the process by which unrelated species become more similar as they adapt to the same kind of environment.
How many mass extinctions have there been
5
Population
A group of living things of the same species that live in a specific area
Convergent Evolution results in what
Analogous structures (butterfly and bird)
Domesticated animals
Artificial Selection
Community is still
Biotic (living), ecosystem (abiotic nonliving + biotic)
Darwin
Descent with modification, which states that newer species in the fossil record are modified descendants of older species (Lamarck, new animals are like old animals with slight modification) Modification by natural selection, which states that organisms to theirr environment are more likely and reporduce Went to Galapagos and South America
Hypothesis became
During his travels, Darwin made numerous observations and collected evidence that led him to propose a hypothesis about the way life changes over time. That hypothesis has become the theory of evolution (aka theory of natural selection).
Fiddler Crab and big claw
Eventually fiddler crabs grew because they used it repeatedly,
Darwin's hypothesis relied on what 2 assumptions
For beak size and shape to evolve, there must be enough heritable variation in those traits to provide raw material for natural selection. Differences in beak size and shape must produce differences in fitness, causing natural selection to occur.
The what of two populations must become separated for them to become new species.
Gene pool
Darwin Publication of On the Origin of Species
He shelved his manuscript for hears and told his wife to publish it in case he died In 1858, Alfred Wallace sent an essay to Darwin for review. Wallace's ideas summarized Darwin's work In 1859 he published the book
This understanding of geology influenced Darwin
If the Earth could change over time, life might change as well. It would have taken many years for life to change in the way Lyell suggested. This would have been possible only if the Earth were extremely old.
Law of Use and Disuse
If you don't use it, you lose it WHICH IS WRONG
Voyage of the Beagle
In 1831, Darwin set sail from England aboard the H.M.S. Beagle for a voyage around the world.
Lyell's Principles of Geology
Lyell stressed that scientists must explain past events in terms of processes that they can actually observe. The processes that shaped the Earth millions of years earlier continue in the present.
Extinction
More than 99% species that ever lived are now extinct Mass extinction provided ecological opportunities for organisms that survived resulted in bursts of evolution that produced many new species
What is the DRIVING FORCE OF EVOLUTION
Natural Selection
His observations
Observed many plants and animals were well suited to environments Puzzled where specides lived and didn't love Fossils Observed that the islands were close, but had different climates
Who tested Darwin's hypothesis
Peter and Rosemary Grant
Catastrophism
Principle that states that geological change occurs suddenly Today scientists agree that, while most changes is gradual and uniform, catastrophes do occur occassionally
Evolution
Process of which populations change over time By which modern organisms have descended from ancient organisms
Physical Adaptation
Structural Adaptation
Compared processes in nature to artificial selection
The Struggle for Existence Darwin realized that high birth rates and a shortage of life's basic needs would force organisms to compete for resources.
Fitness
The ability of an individual to survive and reproduce in its specific environment NOT JUST TO SURVIVE Which is the most fit bird with nest of 4 birds or nest with 5 birds 5 BIRDS BECAUSE REPRODUCTION
Survival of the Fittest
The ability of an individual to survive and reproduce in its specific environment is fitness. Darwin proposed that fitness is the result of adaptations. An adaptation is any inherited characteristic that increases an organism's chance of survival.
Coevolution
The process by which two species evolve in response to changes in each other over time (Pollination)
Uniformintarianism
Theory that geological processes from the past can be explained or understood in terms of the geological processes, forces, or phenomena at work in the present Basically everything is very slow, gradual process over time THE PROCESSES THEMSELVES TO CHANGE THE EARTH HAVE NEVER CHANGED
Wondered if they were from same species
They were from same ancestor species
Basic Divisions of geologic time scale
eras and periods.
6 Important topics in macroevolution
extinction adaptive radiation convergent evolution coevolution punctuated equilibrium changes in developmental genes
Speciation in the finches occurred by
founding of a new population geographic isolation changes in new population's gene pool reproductive isolation ecological competition
Punctuated Equilibrium
is a pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change.
Half-life
is the length of time required for half of the radioactive atoms in a sample to decay.
Radioactive Dating
is the use of half-lives to determine the age of a sample.
Temporal Isolation
occurs when two or more species reproduce at different times.
Behavioral Isolation
occurs when two populations are capable of interbreeding but have differences in courtship rituals or other reproductive strategies that involve behavior.
Relative Dating
the age of a fossil is determined by comparing its placement with that of fossils in other layers of rock. Rock layers form in order by age—the oldest on the bottom, with more recent layers on top.
Jean Baptiste de Lamarck Theory of Acquired Traits/Characteristics
was the first person to clearly state the theory that types of organisms change over time and that new types of organisms are modified descendants of older types (i.e. armadillos being like descendants of dinosaurs) <----This was right To explain how species change, Lamarck INCORRECTLY hypothesized that traits were acquired through an organism's experience or behavior and were passed on to its offspring. We now know that individuals do not evolve; populations do. 1 experiment was chopping tails of mice, this disproved Lamarck Lamarck experiment used webbed feet that supposedly came from compression
