Unit 7 AP biology

What is evolution

Evolution is the change in the genetic makeup of a population over time.

What is adaptation

Adaptation is a characteristic or trait that improves an organism’s ability to survive and reproduce in a specific environment.

What is evolutionary fitness

Evolutionary fitness refers to an organism’s ability to survive, reproduce, and pass on its genes to the next generation.

Explain the process of natural selection

Natural selection is the process by which individuals with advantageous traits are more likely to survive and reproduce, passing those traits to the next generation.

What are the roles of competition, variation, reproductive success, and heritability in natural selection

Competition for resources leads to survival of the fittest; variation in traits allows some individuals to be better suited to the environment; reproductive success ensures these traits are passed on; heritability ensures that beneficial traits are inherited by offspring.

What are the sources of variation

Mutations, sexual reproduction, and genetic recombination are sources of variation.

How does ecosystem stability affect the rate of evolution

Stable ecosystems may have slower rates of evolution due to less environmental change, while unstable ecosystems may drive faster evolutionary change.

Why is variation important to a population faced with environmental change?

Variation increases the likelihood that some individuals will have traits that allow them to survive and reproduce under changing environmental conditions.

What is selective pressure

Selective pressure refers to environmental factors that influence which individuals survive and reproduce, often based on their traits.

How do humans influence evolution through artificial selection?

Humans selectively breed organisms with desirable traits to influence the evolution and variation of species.

What is convergent evolution?

Convergent evolution is the process by which unrelated species evolve similar traits due to similar environmental pressures.

What are analogous structures?

Analogous structures are body parts that serve similar functions in different species but evolved independently, often due to convergent evolution.

What is a population

A population is a group of individuals of the same species living in the same area and interbreeding.

What is a gene pool?

A gene pool is the total collection of genes and alleles in a population

What is microevolution

Microevolution is the change in allele frequencies within a population over time.

How can natural selection, sexual selection, mutations, genetic drift, and migration contribute to evolution?

These mechanisms alter allele frequencies in a population, driving evolutionary change.

What is the bottleneck effect

The bottleneck effect occurs when a population's size is drastically reduced, leading to a loss of genetic variation.

What is the founder effect

The founder effect occurs when a small group of individuals establishes a new population, leading to reduced genetic variation.

What is Hardy-Weinberg equilibrium

Hardy-Weinberg equilibrium is a condition where allele frequencies in a population remain constant over generations, indicating no evolution.

What are the conditions for Hardy-Weinberg equilibrium

Large population size, no migration, no mutations, random mating, and no natural selection.

How do you calculate allele and genotype frequencies using Hardy-Weinberg equations

Use the equation p2+2pq+q2=1 to calculate genotype frequencies and p+q=1 for allele frequencies, where p and q represent the frequencies of two alleles.

What disciplines provide evidence for evolution

Fossil records, comparative anatomy, embryology, and molecular biology provide evidence for evolution.

How do fossils provide evidence for evolution

Fossils show changes in species over time and reveal intermediate forms that support the theory of evolution.

What are homologous and vestigial structures

Homologous structures are body parts in different species that have a common evolutionary origin but may serve different functions. Vestigial structures are remnants of traits that had a function in ancestors but are no longer useful.

How do molecular sequences support evolution

Similarities in DNA and amino acid sequences across species indicate common ancestry.

What are the three domains of life

The three domains of life are Eubacteria, Archaea, and Eukarya.

What evidence supports the relatedness of the three domains of life

Genetic data, such as similarities in rRNA sequences, show that all three domains share a common ancestor.

What evidence supports the relatedness of eukaryotes

Similarities in the genetic makeup of all eukaryotes, as well as shared cellular structures, support their common ancestry.

What are transitional fossils

Transitional fossils are fossils that show intermediate stages between different groups of organisms, providing evidence for the gradual process of evolution.

How is life continuing to evolve today

Examples like pesticide resistance and antibiotic resistance demonstrate ongoing evolutionary change in species.

What is a molecular clock

A molecular clock is a method used to estimate the time of divergence between species based on the number of genetic mutations accumulated over time.

What is the significance of nodes on a phylogenetic tree/cladogram

Nodes represent common ancestors from which different species or groups evolved, showing the point of divergence.

What are shared ancestral and shared derived characteristics

Shared ancestral characteristics are traits inherited from a common ancestor and present in multiple lineages. Shared derived characteristics are traits that evolved in the most recent common ancestor and are unique to its descendants.

What is an outgroup in a cladogram

An outgroup is a species or group that is outside the group being studied, used as a reference point to determine the evolutionary relationships of the ingroup.

How do you analyze a phylogenetic tree/cladogram to determine the relatedness of species

The closer two species are to each other on a cladogram, the more closely related they are, sharing more recent common ancestors.

What types of data are used to construct a phylogenetic tree/cladogram

Morphological data, molecular (DNA, RNA, and protein) sequences, and behavioral data are often used to build phylogenetic trees.

What is parsimony in phylogenetic analysis

Parsimony is the principle that the simplest explanation, requiring the fewest evolutionary changes, is preferred when constructing phylogenetic trees.

What is macroevolution

Macroevolution refers to large-scale evolutionary changes that occur over long periods, including the formation of new species and higher taxonomic groups.

What is the biological species concept

The biological species concept defines a species as a group of organisms that can interbreed and produce fertile offspring, but are reproductively isolated from other such groups.

How does speciation occur

Speciation occurs when a population becomes reproductively isolated from other populations, leading to genetic divergence and the formation of new species.

What are pre-zygotic and post-zygotic reproductive barriers?

Pre-zygotic barriers prevent mating or fertilization (e.g., temporal isolation, behavioral isolation), while post-zygotic barriers occur after fertilization, preventing successful reproduction (e.g., hybrid sterility).

What is allopatric speciation

Allopatric speciation occurs when a population is geographically separated, leading to reproductive isolation and the formation of new species.

What is sympatric speciation

Sympatric speciation occurs when new species arise from a population that shares the same geographic area, often due to behavioral, ecological, or genetic factors.

What is adaptive radiation

Adaptive radiation is the rapid diversification of a species into different forms that occupy different ecological niches.

What is punctuated equilibrium

Punctuated equilibrium is a model of evolution where species experience long periods of stability interrupted by rapid bursts of evolutionary change.

What is gradualism

Gradualism is the model of evolution that suggests species evolve slowly and steadily over time.

What situations can increase extinction rates

Habitat destruction, climate change, overhunting, pollution, and invasive species can increase extinction rates (HIPOC)

How do extinction and speciation affect biodiversity

Extinction decreases biodiversity, while speciation increases it. The balance between both processes affects the overall diversity of life.

How can extinction lead to adaptive radiation

After an extinction event, available ecological niches allow surviving species to rapidly diversify and adapt, leading to adaptive radiation.

What is heterozygote advantage

Heterozygote advantage occurs when individuals with two different alleles for a gene have a higher fitness than individuals with two identical alleles, helping maintain genetic variation in a population.

What is frequency-dependent selection

Frequency-dependent selection is when the fitness of a phenotype depends on how common or rare it is in the population, maintaining variation by favoring less common phenotypes.

What are the types of natural selection

Stabilizing selection favors intermediate phenotypes

disruptive selection favors extreme phenotypes

directional selection favors one extreme phenotype

When did Earth form

Earth formed approximately 4.5 billion years ago

When were conditions on Earth suitable for life

Earth’s conditions became suitable for life around 3.8 billion years ago, when the atmosphere and environment allowed the formation of organic molecules.

What was Miller and Urey's experiment

Miller and Urey's experiment demonstrated how organic molecules, such as amino acids, could form from simple chemicals under conditions simulating early Earth.

Why was the lack of oxygen important for early Earth

The absence of oxygen allowed for the formation of organic molecules through chemical reactions, as oxygen would have broken down those molecules.

How could organic molecules have been brought to Earth other than by abiotic synthesis

Organic molecules may have been delivered by comets or meteorites from space

What is the RNA world hypothesis

The RNA world hypothesis suggests that RNA molecules were the first self-replicating systems, forming the basis for life before DNA and proteins.