AP Bio Unit 7 Supreme Flashcards

All of Unit 7!!

Cyanobacteria

The earliest fossil evidence of life on Earth, dating back to 3.5 billion years ago.

RNA World Hypothesis

A theory proposing that RNA was the earliest genetic material and explains the pre-cellular stage of life.

Oparin and Haldane Hypothesis

Posited that early Earth was primarily composed of hydrogen, methane, ammonia, and water, which could have led to the formation of organic molecules.

Experimental Data

Research conducted by Stanley Miller and Harold Urey that demonstrated organic compounds, including amino acids, could form under early Earth conditions.

Macromolecules

Large complex molecules formed from organic molecules that serve as the building blocks of life.

Meteorites

Celestial bodies that may have transported organic molecules to Earth, contributing to the origins of life.

4.6 billion years ago (bya)

The approximate time when Earth was formed.

3.9 billion years ago (bya)

The time when early Earth became suitable for life.

Species

A group capable of interbreeding and producing viable, fertile offspring.

Speciation

The formation of new species, resulting in diversity of life forms.

Allopatric Speciation

Speciation occurring when populations are geographically isolated by physical barriers.

Sympatric Speciation

Speciation that occurs when new species evolve from a single ancestral species while inhabiting the same geographic region.

Prezygotic barriers

Factors that prevent mating or fertilization between species.

Postzygotic barriers

Factors that prevent hybrid zygotes from developing into viable, fertile adults.

Habitat isolation

When species live in different areas or occupy different habitats within the same area.

Temporal isolation

When species breed at different times of the day, year, or season.

Behavioral isolation

When unique behavioral patterns and rituals separate species.

Mechanical isolation

When reproductive anatomy of one species does not fit with the anatomy of another species.

Gametic isolation

When proteins on the surface of gametes prevent the egg and sperm from fusing.

Reduced hybrid viability

When the genes of different parent species interact in ways that impair the hybrid’s development or survival.

Reduced hybrid fertility

When a hybrid develops into a healthy adult but is sterile.

Hybrid breakdown

When the hybrid of the first generation is fertile, but their offspring are sterile.

Microevolution

Change in allele frequencies within a single species or population.

Macroevolution

Large evolutionary patterns that occur over significant time spans.

Punctuated equilibrium

Evolution occurring rapidly after a long period of stasis.

Gradualism

Evolution occurring slowly over extended periods of time.

Divergent evolution

When groups with the same common ancestor evolve and accumulate differences.

Convergent evolution

When two different species develop similar traits despite having different ancestors.

Extinction

The termination of a species.

Phylogeny

The evolutionary history of a group of organisms.

Systematics

The classification of organisms and determining their evolutionary relationships.

Taxonomy

The science of naming and classifying species.

Phylogenetics

The hypothesis of evolutionary history, often represented through phylogenetic trees.

Phylogenetic Trees

Diagrams that represent the evolutionary history of a group of organisms, showing the amount of change over time.

Cladograms

A diagram that shows relationships among species, with each line representing a lineage and branching points as nodes.

Node

A point in a phylogenetic tree where a lineage splits, representing a common ancestor.

Clade

A group of species that includes a common ancestor and all its descendants.

Sister Taxa

Two clades that emerge from the same node.

Basal Taxon

A lineage that evolved from the root and remains unbranched.

Synapomorphy

A derived character shared by clade members.

Derived Characteristic

Similarity inherited from the most recent common ancestor of an entire group.

Ancestral Characteristic

Similarity that arose prior to the common ancestor.

Outgroup

A lineage that is the least closely related to the rest of the organisms in a study.

Monophyletic Group

A group that includes the most recent common ancestor of the group and all its descendants.

Paraphyletic Group

A group that includes the most recent common ancestor but not all its descendants.

Polyphyletic Group

A group that does not include the most recent common ancestor of all its members.

Principle of Parsimony

The hypothesis that requires the fewest assumptions is preferred when there are conflicts among characters.

Fossil Record

Gives a visual of evolutionary change over time through remains or traces of past organisms.

Comparative Morphology

Analysis of the structures of living and extinct organisms to identify similarities and differences.

Homology

Characteristics in related species with similarities despite differing functions.

Vestigial Structures

Structures that are conserved in species even though they no longer serve a useful function, like the human tailbone and appendix.

Molecular Homology

Similarity of DNA and amino acid sequences across different species, indicating common ancestry.

Convergent Evolution

Similar adaptations evolved in distantly related organisms due to similar environmental pressures.

Analogous Structures

Structures that are similar in function but have different evolutionary origins, like the wings of birds, bats, and bees.

Biogeography

The geographical distribution of animals and plants, providing evidence for evolution.

Natural Selection

The process by which structures can become vestigial if they were once useful but have mutated to become unnecessary.

Eukaryotes

Organisms whose cells have membrane-bound organelles and linear chromosomes, supporting common ancestry.

Population Genetics

The study of genetic variation within populations and how these variations change over time.

Gene Pool

The total genetic diversity found within a population, consisting of all alleles at all loci in individuals.

Microevolution

Small-scale changes in allele frequency within a population.

Mutations

Changes in the DNA sequence that can introduce new alleles.

Genetic Drift

Random changes in allele frequencies that are more significant in small populations.

Bottleneck Effect

A drastic reduction in population size due to an environmental event, leading to over or under-representation of alleles.

Founder Effect

Occurs when a small number of individuals start a new population with a different allele frequency from the source population.

Gene Flow

The transfer of alleles between populations through the movement of individuals or gametes.

Natural Selection

A mechanism of evolution where individuals with advantageous traits survive and reproduce more successfully.

Directional Selection

A mode of natural selection that favors one extreme phenotype.

Stabilizing Selection

A mode of natural selection that favors the average phenotype, reducing variation.

Disruptive Selection

A mode of natural selection that favors extreme phenotypes over the average.

Hardy-Weinberg Equilibrium

A hypothetical scenario where allele frequencies remain constant in a population, indicating no evolution.

p + q = 1

The formula representing the relationship between the frequencies of two alleles in a population.

p² + 2pq + q² = 1

The formula for calculating genotype frequencies in a population.

Natural Selection

A process in which individuals with certain traits tend to survive and reproduce at higher rates due to those traits.

Charles Darwin

English naturalist known for his research on evolution and natural selection, particularly at the Galapagos Islands.

Biogeography

The geographic distribution of species; a field of study that Darwin was interested in.

Descent with Modification

A modern definition of evolution proposed by Darwin, describing the change in genetic makeup of a population over time.

Adaptations

Inherited characteristics of organisms that enhance their survival and reproduction.

Artificial Selection

The selective breeding of domesticated plants and animals to encourage desirable traits.

Heritable Traits

Characteristics that can be passed from parent to offspring, contributing to evolution.

Favorable Traits

Traits that lead to survival and reproduction, accumulating in the population over time.

Phenotypic Variations

Observable differences in traits among individuals in a population that natural selection acts upon.

Evolution

Change in the genetic makeup of a population over time; includes concepts of descent with modification.

Convergent evolution

The process where unrelated or distantly related organisms develop similar characteristics or adaptations in response to comparable environmental challenges.

Divergent evolution

The phenomenon in which related species become increasingly different over time, often driven by various environmental influences and the need for different adaptations.