chapter 1 Flashcards
Phenomenon
something in nature that we wish to explain
Hypotheses
educated guesses of cause and effect
Theory
the conceptual framework within which our hypotheses are framed
Predictions
logical deductions of our hypotheses (predictions must be independent of the data or knowledge that went into formulating our hypotheses)
Tests
empirical falsification or verification of our predictions
Biological evolution
Any change in the inherited traits of a population that occurs from one generation to the next
What does evolution explain?
The diversity of life
Evolutionary case studies
Whales:mammals gone to sea. Viruses: deadly escape artists.
Lineage
A chain of ancestors and their descendants. A lineage may be the successive generations of organisms in a single population, the members of an entire species during an interval of a million years, or a group of related species descending from a common ancestor.
Natural Selection
A mechanism that can lead to evolution, whereby differential survival or reproduction of individuals causes some genetic types to replace (out complete) others.
Convergent evolution
the independent origin of similar traits in seperate lineages.
Homologous
characteristics are similar in two or more species because they are inherited from a common ancestor.
Synapomorphy
derived form of a trait that is shared by a group of related (i.e. one that evolved in the immediate common ancestor of the group and was inherited by all its descendants).
Phylogeny
A visual representation of the evolutionary history of populations, genes, or species.
Mutation
any change to the genomic sequence of an organism.
Reassortment
Viral reassortment occurs when genetic material from different strains gets mixed into new combinations within a single individual.
Molecular Clock
technique in molecular evolution that uses fossil constraints and rates of molecular change to deduce the time in geologic history when two species or other taxa diverged.
How did whales and fish lineages evolve?
independently, converged on body forms that are superficially similar.
Ambulocetus
fossil whale that had legs. The animal had traits that were intermediate between modern whales and their terrestrial ancestors.
What does the chemistry of fossil whales document?
A transition from land to estuaries to the open ocean- the same transition documented in the changing shape of their skeletons.
What synapomorphies do whales share with mammals?
Mammary glands
– Three middle ear bones
– Hair (in developing embryos)
How did whales similarities with fish arise?
convergent evolution
Whales and seals…
evolved flippers independently through convergent evolution.
The concept of Uniformitarianism traces back to…
James Hutton
Which allows for rapid evolution of influenza virus?
- High mutation rate
- High reproductive rate
Which structure in fossil whales suggests that they are related to artiodactyls?
- The anklebone
- Astragalus
Who co-discovered the theory of evolution?
Alred Russell Wallace
What helps document the transition from land to water?
isotopic analysis of fossil teeth, fossil analysis of hindlimb loss.
Explain Isotopic analysis:
Terrestrial animals drink freshwater; marine animals drink saltwater
• O18/O16 ratio higher in saltwater
– Higher ratio in teeth of marine animals
Explain Hindlimb loss:
-Fossils document hindlimb loss
-Changes in gene expression led to hindlimb loss
• Hindlimbs begin to form but do not fully develop
-Fossils of whales document the gradual reduction and simplification of pelvis.
What evidence is present for the evolution of whales from terrestrial mammal ancestors?
Whales start the process of hind limb development.
Explain Hemagglutinin and its significance:
A protein on the surface of the influenza virus that latches it to a host cell; it is also the protein that is recognize by our immune system, and it is harvested to manufacture vaccines(the flu shot). This viral protein evolves extremely rapidly, rendering our vaccines obsolete months after they made.
What is so dangerous about reassortment of the influenza virus?
It could blend dangerous elements of pig or bird flu with the infectious potential of human flu, instantaneously generating a deadly and infectious strain.
How can we map virus lineages?
Mutations arise at a roughly steady rate, and so the number of different mutations in two lineages provides a clue to how long ago they diverged from a common ancestor.
Explain evolution of whale teeth:
Ancestors of whales had teeth and small patches of baleen Baleen completely replaced teeth in Mysticetes – Genes for building teeth disabled
Cetacean brain evolution:
Sociality promoted the evolution of large brains
– Form lasting alliances
– Competition for mates
– Complex communication
Genetic drift:
evolution arising from random changes in the genetic composition of a population from one generation to the next.
Phenotype-
Measurable aspects of organisms, such as morphology(structure), physiology, and behavior. Genes interact with other genes and with the environment during the development of the phenotype.
Why is evolution not “just a theory”?
Scientific theories backed by multiple lines of evidence
– Provide overarching explanation for major aspects of natural world
Common Misconceptions about Evolution:
1) Evolution is “just” a theory
2) Evolutionary biologists understand everything about the history of life
3) Evolution explains the origin of life
4) Evolutionary biologists search for missing links
5) Evolution violates the second law of thermodynamics
6) Evolution is natural selection
7) Evolution is entirely random
8) Organisms evolve adaptations they “need”
9) Evolution is a march of progress
10) Evolution always moves from simple to complex
11) Evolution results from individuals adapting to environment
12) Organisms are perfectly adapted to their environment
13) Evolution happens for the good of the species
14) Evolution promotes selfishness and cruelty
15) Evolution seeks peaceful harmony in nature
16) Life can be divided into higher and lower forms
17) Evolution has produced a stable diversity of life
True or False: Mutations are errors that arise when DNA is replicated.
True
T or F: New mutations cause individuals to differ from each other genetically
True
T or F: Natural selection and genetic drift are mechanisms of evolution, because they can cause the genetic composition of the population to shift from generation to generation.
T
T or F:Natural selection occurs when some genetic types of individuals survive and reproduce more successfully than others
T
T or F: Evolution responds to an individual’s need
False
T or F: Evolution produces complex adaptations, and moves toward a
particular goal.
false
T or F: Evolutionary biologists test hypotheses about evolution using many different lines of evidence.
T
T or F: Whales evolved from land mammals about 50 million years ago. Evolution has shaped many aspects of their biology, from their behavior to aging.
T
T or F: The rapid evolution of influenza virus makes it difficult to fight
T
