evolutionary bio exam 1 study guide

What is evolution?

Evolution is the change in the heritable characteristics of biological populations over successive generations, driven by processes such as natural selection, mutation, gene flow, and genetic drift.

What is natural selection?

Natural selection is the process by which organisms better adapted to their environment tend to survive and produce more offspring, leading to the gradual evolution of species.

What is genetic drift?

Genetic drift is a mechanism of evolution that refers to random changes in the frequency of alleles in a population, which can lead to significant changes over time, especially in small populations.

What is mutation?

Mutation is a change in the DNA sequence of an organism's genome, which can lead to new traits that may be beneficial, harmful, or neutral in terms of survival and reproduction.

What is gene flow?

Gene flow is the transfer of genetic material between populations, which can increase genetic diversity and reduce differences between populations.

What is speciation?

Speciation is the evolutionary process by which populations evolve to become distinct species, often due to geographic isolation or differing environmental pressures.

What is a common ancestor?

A common ancestor is an ancestral species from which two or more descendant species have evolved, providing evidence for the evolutionary relationships among species.

What is adaptive radiation?

Adaptive radiation is the rapid evolution of diversely adapted species from a common ancestor, often occurring when a species colonizes a new environment with varied ecological niches.

What is convergent evolution?

Convergent evolution is the process by which unrelated or distantly related organisms evolve similar traits or adaptations in response to similar environmental challenges.

What is divergent evolution?

Divergent evolution is the accumulation of differences between closely related species, often due to different environmental pressures or ecological niches.

What is artificial selection?

Artificial selection is the intentional breeding of organisms by humans for specific traits, leading to changes in the genetic makeup of a population.

What is fitness in evolutionary biology?

Fitness refers to an organism's ability to survive and reproduce in its environment, often measured by the number of offspring produced that survive to reproductive age.

What is a phenotype?

A phenotype is the observable physical or biochemical characteristics of an organism, determined by both genetic makeup and environmental influences.

What is a genotype?

A genotype is the genetic constitution of an organism, representing the specific alleles inherited from its parents.

What is a fossil?

A fossil is the preserved remains or traces of ancient organisms, providing evidence for the history of life and evolutionary changes over time.

What is the fossil record?

The fossil record is the chronological collection of life's remains in sedimentary rock layers, offering insights into the history of life and evolutionary processes.

What is homology?

Homology refers to similarities in structure or function between different species that arise from a common ancestor, indicating evolutionary relationships.

What is analogy?

Analogy refers to similarities in function or appearance between different species that arise from convergent evolution, not from a common ancestor.

What is a cladogram?

A cladogram is a diagram that shows the evolutionary relationships among various species based on shared characteristics, illustrating the branching patterns of evolution.

What is phylogenetics?

Phylogenetics is the study of the evolutionary history and relationships among individuals or groups of organisms, often using genetic data to construct evolutionary trees.

What is extinction?

Extinction is the permanent loss of a species, which can occur due to various factors including environmental changes, loss of habitat, and competition.

What is coevolution?

Coevolution is the process by which two or more species influence each other's evolution, often seen in predator-prey relationships or mutualistic interactions.

What is a niche?

A niche is the role or function of an organism or species within an ecosystem, including its habitat, resource use, and interactions with other organisms.

What is biodiversity?

Biodiversity refers to the variety of life in a particular habitat or ecosystem, encompassing species diversity, genetic diversity, and ecosystem diversity.

What is the theory of punctuated equilibrium?

The theory of punctuated equilibrium proposes that species remain relatively stable for long periods, interrupted by brief episodes of rapid evolutionary change.

What is a population?

A population is a group of individuals of the same species that live in a specific area and interbreed, sharing a common gene pool.

What is sexual selection?

Sexual selection is a form of natural selection where individuals with certain traits are more likely to attract mates, leading to the evolution of those traits.

What is allopatric speciation?

Allopatric speciation occurs when a population is geographically isolated, leading to the evolution of distinct species due to lack of gene flow.

What is sympatric speciation?

Sympatric speciation occurs when new species evolve from a single ancestral species while inhabiting the same geographic region, often through mechanisms like polyploidy.

What is a gene pool?

A gene pool is the total collection of genes and their alleles in a population, representing the genetic diversity available for evolution.

What is a vestigial structure?

A vestigial structure is a body part that has lost its original function through evolution, such as the human appendix or the remnants of hind limbs in whales.

What is the Hardy-Weinberg principle?

The Hardy-Weinberg principle describes the conditions under which allele frequencies in a population remain constant over generations, indicating no evolution is occurring.

What is a transitional fossil?

A transitional fossil is a fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group, providing evidence for evolution.

What is endemism?

Endemism refers to a species that is native to and restricted to a specific geographical area, often resulting from evolutionary processes in isolated environments.

What is the significance of genetic variation?

Genetic variation is crucial for a population's ability to adapt to changing environments, as it provides the raw material for natural selection to act upon.

What is the role of environmental pressures in evolution?

Environmental pressures, such as climate change, resource availability, and predation, influence which traits are favorable for survival and reproduction, guiding the process of evolution.

What is the significance of the Galápagos Islands in evolutionary biology?

The Galápagos Islands are significant in evolutionary biology for their unique species and the insights they provide into natural selection and adaptive radiation, famously studied by Charles Darwin.

Current and past distributions of the HIV-1 pandemic

The HIV-1 pandemic has evolved over time, with varying distributions influenced by factors such as transmission rates, social behavior, and public health interventions.

Life cycle of HIV

HIV infects people by targeting CD4+ T cells, integrating its genetic material into the host's DNA, leading to cell death and the progression to AIDS, which is characterized by a severely weakened immune system.

How AZT and other drugs stopped HIV progression

AZT (zidovudine) inhibits reverse transcriptase, preventing HIV from replicating. However, resistance can develop, leading to treatment failure.

Current state of cures for AIDS

While there are effective treatments for managing HIV, challenges include viral reservoirs, stigma, and the complexity of the virus. The Berlin and London patients were cured through stem cell transplants from donors with a rare genetic mutation.

Transmission Rate Hypothesis

This hypothesis suggests that the rate of HIV transmission is influenced by factors such as viral load, sexual practices, and the presence of other sexually transmitted infections.

Origins of HIV-1 and HIV-2

HIV-1 originated from simian immunodeficiency virus (SIV) in chimpanzees, while HIV-2 is derived from SIV in sooty mangabey monkeys.

Basic premise of the SARS-CoV-2 origins discussion

The discussion paper examines the origins of SARS-CoV-2, considering zoonotic transmission and the role of intermediate hosts in the emergence of the virus.

What is biological evolution?

Biological evolution is the change in the heritable characteristics of biological populations over successive generations, driven by processes such as natural selection, mutation, and genetic drift.

Who was Charles Darwin?

Charles Darwin was a naturalist who proposed the theory of evolution by natural selection, influenced by the scientific atmosphere of the 19th century and contributions from other scientists like Wallace and Lyell.

Lamarck and Wallace's contributions

Lamarck proposed the idea of inheritance of acquired characteristics, while Wallace independently conceived the theory of natural selection, prompting Darwin to publish his findings.

Examples of evidence for evolution

Evidence for evolution includes fossil records, comparative anatomy, molecular biology, and observed instances of natural selection, demonstrating that evolution occurs over time.

Geologists' contributions to evolution evidence

Geologists provided evidence of Earth's age and the gradual changes in the fossil record, supporting the concept of deep time necessary for evolutionary processes.

Darwin's finches and natural selection

Darwin's finches are a classic example of natural selection, where variations in beak size and shape allowed different species to adapt to available food sources on the Galápagos Islands.

Importance of heritability in natural selection

Heritability is crucial for natural selection, as traits must be passed on to offspring for evolution to occur. Measuring heritability can be complex due to environmental influences.

Darwin's Four Postulates

Darwin's Four Postulates state that variation exists, some variations are heritable, individuals compete for resources, and those with advantageous traits are more likely to survive and reproduce.

Evidence from artificial selection

Darwin used examples of artificial selection, such as dog breeding, to illustrate how selective pressures can lead to significant changes in species over time, analogous to natural selection.

Research by the Grants on the Galápagos Islands

The Grants studied finch populations on the Galápagos Islands, demonstrating natural selection in action through changes in beak size in response to food availability during droughts.

Darwin's problems with his theory

Darwin faced challenges such as the lack of a mechanism for inheritance and the sudden appearance of complex traits, which have since been addressed through genetics and modern evolutionary synthesis.

Criticisms of evolution by Creationists

Creationists argue against evolution using misconceptions about complexity and gaps in the fossil record, but scientific evidence supports evolution through extensive research and data.

Definitions of fitness, adaptation, homology, systematics, phylogeny, and taxonomy

Fitness refers to an organism's ability to survive and reproduce; adaptation is a trait that enhances fitness; homology indicates shared ancestry; systematics is the study of classification; phylogeny is the evolutionary history of a species; taxonomy is the classification of organisms.

Linnaeus's contributions to classification

Carl Linnaeus developed the binomial nomenclature system for naming species and laid the foundation for modern taxonomy by organizing organisms into hierarchical categories.

Differences between synapomorphies, autapomorphies, and (sym)pleisiomorphies

Synapomorphies are shared derived traits used to infer evolutionary relationships, autapomorphies are unique derived traits, and (sym)pleisiomorphies are shared ancestral traits, important for phylogenetic reconstruction.

Different types of homoplasy

Homoplasy refers to traits that arise independently in different lineages, including convergent evolution and evolutionary reversals, complicating phylogenetic analysis.

Assumptions for characters in phylogenetic analysis

Assumptions include that characters are heritable, independent, and that the evolutionary changes are consistent across lineages, allowing for accurate tree construction.

How trees are rooted with outgroups

Phylogenetic trees are rooted using outgroups, which are closely related but distinct species, to establish the direction of evolutionary change and provide a reference point.

Evidence for the placement of Cetacea in artiodactyl mammals

Molecular and morphological evidence supports that cetaceans (whales and dolphins) are closely related to artiodactyls (even-toed ungulates), sharing a common ancestor.

Tree terminology and reading phylogenetic trees

Key terms include nodes (branching points), branches (lineages), and tips (extant species). Reading trees involves understanding relationships and evolutionary distances between species.

How to make a character matrix for phylogenetic trees

A character matrix is created by listing species and their traits, which can then be analyzed to build a phylogenetic tree based on shared characteristics.

Features of maximum parsimony, distance methods, maximum likelihood, and Bayesian analysis

Maximum parsimony minimizes the number of changes; distance methods calculate genetic distance; maximum likelihood estimates the probability of observed data; Bayesian analysis incorporates prior knowledge and provides posterior probabilities.

Assessing confidence in trees and nodes

Confidence in phylogenetic trees can be assessed using bootstrapping, which tests the robustness of tree branches, and posterior probability in Bayesian analysis, indicating the likelihood of a hypothesis.

Molecular clocks and clock-like evolution

Molecular clocks use mutation rates to estimate the timing of evolutionary events, assessing whether taxa evolve at a consistent rate over time.

What is monophyly?

Monophyly refers to a group of organisms that includes a common ancestor and all its descendants, while non-monophyly includes groups that do not meet this criterion.

Using phylogenetic trees to answer questions

Phylogenetic trees can be used to infer evolutionary relationships, trace the history of traits, and understand the processes that led to diversification among species.

Different types of variation among individuals

Variation can be genetic (due to alleles), environmental (due to external factors), or G x E (gene-environment interactions), influencing phenotypic traits.

Determining genetic, environmental, or G x E variation

To determine the source of variation, experiments can be conducted to isolate genetic factors, control environmental conditions, and analyze interactions between genes and the environment.

Types of mutations creating new alleles, genes, or species

Mutations such as point mutations, insertions, deletions, and duplications can create new alleles; larger genomic changes can lead to new genes, and speciation often involves reproductive isolation and genetic divergence.

SARS-CoV-2 evolution discussion question

Discuss the implications of SARS-CoV-2 evolution on public health strategies and vaccine development, considering how mutations affect transmissibility and vaccine efficacy.