Unit 3 Review Flashcards

A collection of flashcards based on the key concepts from Unit 3, focusing on viruses, evolution, natural selection, genetics, and phylogenetics.

What are the three components of the Lyme Disease system?

Host: mouse, deer, or human; Vector: tick carrying Borrelia burgdorferi; Pathogen: Borrelia burgdorferi.

What is the host for COVID-19?

Humans (plus cats, dogs, mink, and others).

What type of pathogen is SARS-CoV-2?

It is a virus that causes coronavirus disease 2019 (COVID-19).

Which famous naturalist said, 'Nothing in Biology makes sense except in the light of evolution'?

Theodosius Dobzhansky.

What are the four stages of natural selection?

1) Variation exists in traits. 2) Differential survival and reproduction. 3) Heritable traits favored. 4) Population changes over generations.

Define evolution.

Evolution is descent with modification; it refers to the change in populations through time.

What are adaptations?

Traits that enhance an organism's chances of survival and reproduction.

What is the significance of the phrase 'survival of the fittest'?

It refers to the differential survival and reproduction of individuals with advantageous traits.

What is a gene?

A distinct sequence of nucleotides forming part of a chromosome.

What is an allele?

Different versions of a gene that can exist for any given trait.

What does the term 'homozygous' mean?

Having two identical alleles for a specific gene.

What does the term 'heterozygous' mean?

Having two different alleles for a specific gene.

Define phenotype.

The physical expression or characteristics of a genotype.

What are the Hardy-Weinberg assumptions?

1) No mutation, 2) Random mating, 3) No gene flow, 4) Infinite population size, 5) No selection.

What does gene flow refer to?

The movement of alleles between populations through migration or dispersal.

What is genetic drift?

A change in allele frequency within a population due to random sampling of organisms.

What is the founder effect?

A form of genetic drift that occurs when a small group establishes a new population.

What is the bottleneck effect?

A significant reduction in population size due to environmental events or human activities.

What is natural selection?

The process by which individuals with advantageous traits survive and reproduce more successfully.

Define mutation.

A change in the DNA sequence that can lead to new alleles.

What are vector-borne diseases?

Diseases transmitted to humans by vectors like mosquitoes or ticks.

What is a phylogeny?

The history of the evolution of a species or group of species.

What is the biological species concept?

Defines species as groups of actually or potentially interbreeding populations that are reproductively isolated.

What is a pre-zygotic isolating mechanism?

Factors that prevent mating or fertilization between species.

What is a post-zygotic isolating mechanism?

Factors that reduce the viability or reproductive capacity of hybrid offspring.

What is allopatric speciation?

Speciation that occurs when populations are geographically isolated.

What is sympatric speciation?

Speciation that occurs without geographical isolation, often through polyploidy or behavioral changes.

What role do intermediaries play in evolution?

They can serve as hosts for pathogens such as viruses and facilitate transmissions.

How do mutations affect evolution?

They introduce new genetic variation and can affect an organism's fitness.

Define artificial selection.

The intentional breeding of plants or animals for specific traits.

What is sexual selection?

A mode of natural selection where individuals with certain traits are more likely to find mates.

What is the relationship between adaptation and fitness?

Adaptations increase an organism's fitness by improving survival and reproductive success.

What is a viral vector?

A virus used to deliver genetic material into cells.

Define 'virus'.

A small infectious agent that replicates only inside the living cells of an organism.

What is the function of the spike protein in SARS-CoV-2?

It attaches to the ACE2 receptor on human cells, facilitating entry into the cell.

What are zoonotic diseases?

Diseases that can be transmitted from animals to humans.

Define ecological adaptation.

Adjustments of organisms to their environments that enhance survival.

What is the primary goal of systematics?

To classify organisms and determine their evolutionary relationships.

What does a phylogenetic tree signify?

The evolutionary history of a group of organisms depicted in a branching diagram.

What is the 'Out of Africa' hypothesis?

The theory that all modern humans originated from a common ancestor in Africa before migrating globally.

What defines a mass extinction event?

A significant and rapid decrease in the biodiversity on Earth, often due to catastrophic events.

What role do viruses play in ecosystems?

Viruses can regulate population sizes of microorganisms, contributing to nutrient cycling.

What are the steps of the scientific method?

1) Observation, 2) Question, 3) Hypothesis, 4) Experiment, 5) Analysis, 6) Conclusion.

Define hypothesis.

A testable prediction about the relationship between variables.

What is the purpose of a control group in an experiment?

To provide a baseline for comparison against the experimental group.

What is a double-blind study?

A study in which neither the participants nor the researchers know who is receiving the treatment to minimize bias.

What is homeostasis?

The maintenance of stable internal conditions in an organism.

What is a trophic level?

A position in a food chain or food web that indicates the organism's role in the energy transfer.

What are primary producers?

Organisms that create energy through photosynthesis or chemosynthesis, forming the base of the food chain.

Define biomagnification.

The process by which the concentration of toxins increases in organisms at each successive trophic level.

What are keystone species?

Species that have a disproportionately large impact on their ecosystem relative to their abundance.

Define ecological niche.

The role and position a species has in its environment, including all interactions with biotic and abiotic factors.

What is the difference between a fundamental niche and a realized niche?

The fundamental niche is the potential mode of existence, while the realized niche is the actual mode of existence due to limiting factors.

What is symbiosis?

A close and long-term interaction between two different species.

What are the three types of symbiotic relationships?

1) Mutualism (both benefit), 2) Commensalism (one benefits, other unaffected), 3) Parasitism (one benefits at the other's expense).

What is succession in ecology?

The process by which ecosystems change and develop over time.

What is primary succession?

Succession that occurs in an area without soil or where no previous ecosystem existed.

What is secondary succession?

Succession that occurs in an area where a disturbance has destroyed an existing ecosystem but soil remains.

What are invasive species?

Non-native species that spread widely in a new habitat and can cause harm to the environment, economy or human health.

Define biodiversity.

The variety of life in the world or a particular habitat or ecosystem.

What is biological magnification?

The process by which the concentration of toxins increases in higher trophic levels.

What is climate change?

Long-term alteration in temperature and typical weather patterns in a place.

Define greenhouse gases.

Gases in the Earth's atmosphere that trap heat, contributing to the greenhouse effect.

What is ecological footprint?

A measure of human demand on the Earth's ecosystems, representing the amount of natural capital used.

What is the purpose of conservation biology?

To study and implement ways to protect biodiversity and manage natural resources.

What is a niche partitioning?

The process by which competing species use the environment differently to coexist.

What is the role of decomposers in an ecosystem?

Decomposers break down dead organic matter, recycling nutrients back into the ecosystem.

Define photosynthesis.

The process by which green plants use sunlight to synthesize foods from carbon dioxide and water.

What is cellular respiration?

The process by which cells convert glucose and oxygen into energy, carbon dioxide, and water.

What is the difference between prokaryotic and eukaryotic cells?

Prokaryotic cells lack a nucleus and membrane-bound organelles, while eukaryotic cells do have these features.

What are chromosomes?

Structures within cells that contain DNA and protein, carrying genetic information.

Define allele frequency.

The proportion of a specific allele among all allele copies in a population.

What is speciation?

The process through which new species arise.

Define extinction.

The end of an organism or a species, occurring when the last individual of the species dies.

What are conservation strategies for protecting endangered species?

Habitat preservation, legal protection, captive breeding programs, and public education.

What does a food web illustrate?

The complex network of feeding relationships among organisms in an ecosystem.

Define ecosystem.

A community of living organisms interacting with their physical environment.

What is carrying capacity?

The maximum population size that an environment can sustain.

What is the significance of the ozone layer?

It protects Earth from harmful ultraviolet radiation from the sun.

What is biodiversity hotspot?

A biogeographic region with significant levels of biodiversity that is under threat from human activities.

Define sociobiology.

The study of social behavior in animals and humans in an evolutionary context.

What are phylogenetic markers?

Traits or genes that can be used to study evolutionary relationships among species.

What is the difference between haploid and diploid cells?

Haploid cells have one set of chromosomes (n), while diploid cells have two sets (2n).

Define genetic variation.

Differences in genes among individuals within a population.

What is the role of natural selection in evolution?

Natural selection leads to the adaptation of species to their environment over time.

What is the ecological importance of wetlands?

Wetlands act as natural water filters, flood control, and habitat for diverse species.

What are the impacts of climate change on ecosystems?

Climate change can lead to shifts in species distributions, altered ecosystem functions, and increased extinction rates.

Define habitat destruction.

The loss of a natural habitat, typically due to human activity, leading to loss of biodiversity.

What is the significance of taxonomic classification?

It organizes biological diversity into hierarchical groups, aiding in identification and study.

Define ecological restoration.

The process of returning an ecosystem to its original structure and function.

What are the characteristics of a density-dependent factor?

Factors that influence population size in relation to the population's density, such as food availability.

What is a dead zone in an aquatic ecosystem?

Areas of water with low oxygen concentrations, often caused by nutrient pollution.

What role do fungi play in ecosystems?

Fungi decompose organic material, recycling nutrients, and can form symbiotic relationships with plants.

What is phenotypic plasticity?

The ability of an organism to change its phenotype in response to environmental factors.

What are ecosystem services?

Benefits that humans obtain from ecosystems, including provisioning, regulating, cultural, and supporting services.

Define biogeography.

The study of the geographic distribution of living organisms.

What is gene therapy?

A technique that modifies a person's genes to treat or prevent disease