30 Questions
What is the term for changes in gene/allele frequency over generations?
Microevolution
What causes new species to emerge?
Speciation
Which process explains the build-up of genetic changes in a population over time?
Genetic drift
What can cause gene pools to become increasingly different from the original pool?
Gene flow
Which barrier leads to the fragmentation of gene pools during speciation?
Geographic isolation
What process occurs when genetic changes result in a population hunting in water versus on land, like Garter snakes?
Behavioral isolation
What is the primary source of gene pools for future speciation?
Survivors of mass extinction events
Which statement best describes homologous structures?
Related species have shared structures inherited from the same gene pool.
Why can species have very different phenotypes despite being closely related?
Caused by divergent evolution
Which pairs of traits are examples of convergent evolution?
Hummingbird and sphinx moth traits
What is the relationship between apes and humans according to the text?
Apes are distant cousins of humans
Which of the following is NOT a theory according to the text?
Guess theory
What is the definition of microevolution?
Changes in genetic composition within a population over generations
What is the primary cause of genetic diversity in a population?
Mutation
What does the term 'gene pool' refer to?
All the genes and alleles in a population
How is the genetic composition of a population measured?
By measuring the frequency of each allele in the gene pool
What is the outcome of gene flow?
It increases the genetic diversity of the population
What is the first mechanism of microevolution?
Mutation
What is the primary cause of allele frequency change in genetic drift?
Allele function is irrelevant to the change.
Which of these circumstances makes genetic drift likely?
The associated phenotype is not an advantage or disadvantage.
What is a population 'bottleneck'?
A population crash over a short time, resulting in the loss of alleles.
What is the definition of 'relative fitness'?
The number of surviving offspring over a lifetime.
What is the primary cause of allele frequency change in natural selection?
The environment determines which phenotypes are higher or lower fitness.
Which of these is an example of natural selection?
Individuals with specific phenotypes are more likely to survive and reproduce in a particular environment.
Which phylum do starfish belong to?
Phylum Echinodermata
What type of endoskeleton do chondrichthyes have?
Cartilage
Which class of chordates includes animals that are the first to colonize land?
Class Amphibia
What is a unique feature of some reptiles that is not a defining mammalian trait?
Placentas
What percentage of all mammals belong to the two most species-rich mammalian orders?
More than 75%
What major event occurs in the life cycle of amphibians?
Metamorphosis
Study Notes
Microevolution
- Microevolution: changes in gene/allele frequency over generations, causing a change in the phenotype of a population over time
- Mechanisms of microevolution:
- Genetic drift: allele frequency change due to chance, regardless of the allele's usefulness
- Natural selection: allele frequency change due to the allele's associated phenotype being an advantage or disadvantage in a particular environment
- Gene flow: migration adds or removes alleles from a gene pool
- Mutations: brand new alleles that can occur before any of the other three mechanisms
Genetic Drift
- Genetic drift: allele frequency change due to chance, regardless of the allele's usefulness
- Circumstances that make drift likely:
- The associated phenotype is not an advantage or disadvantage
- Small populations: more likely to change due to a chance event, regardless of the allele's usefulness
- Population bottleneck: population crashes over a short time, alleles lost regardless of allele value
- If the population begins to increase again, the lost alleles may not be recovered
Natural Selection
- Natural selection: allele frequency change due to the allele's associated phenotype being an advantage or disadvantage in a particular environment
- Allele's associated phenotype is defined as an advantage or disadvantage if it is associated with reproductive success
- Relative fitness: the number of surviving offspring over a lifetime, relative to others in the population
Speciation
- Speciation: the process of population divergence, resulting in new species
- Two key steps:
- Gene pool fragmentation: a reproductive barrier occurs, causing geographic isolation, habitat isolation, behavioral isolation, or temporal isolation
- New gene pools become increasingly different: microevolution, mutations, natural selection, and genetic drift occur, leading to the formation of new species
Patterns of Evolution
- Diversification: new species and whole new lineages occur due to speciation
- Transitional species: have ancestral and new traits, may have intermediate phenotypes
- Homologous structures: related species have shared structures, same source, subsequently modified by natural selection
- Divergent evolution: species can have very different phenotypes even if they are fairly closely related
- Convergent evolution: species can have very similar phenotypes even if they are not closely related
Macroevolution
- Macroevolution: the development of new species and families of species
- Six patterns of evolution:
- Diversification
- Transitional species
- Homologous structures
- Divergent evolution
- Convergent evolution
- Speciation
- Evolution is not a guess, but a scientific theory, like germ theory, cell theory, and genetic theory
Kingdom Characteristics
- Kingdom Plantae: characteristics
- Kingdom Fungi: characteristics
- Kingdom Animalia: characteristics
- Levels of biological organization
Explore the concepts covered in Unit 4 of BIO 105 with Professor Craddock, including microevolution, macroevolution, taxonomy, and biological organization. Learn about genetic diversity, mechanisms of microevolution, and the development of new species and families.
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