Organisms, populations, communities, and species
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Which of the following statements accurately describes the relationship between an organism, population, and community?

  • An organism is a life form, a population is a single species, and a community is a synonym for the same species
  • An organism is a group of same species, a population is a life form and a community is multiple species in the same area.
  • An organism is a life form, a population is a group of same species, and a community is multiple species in the same area. (correct)
  • An organism is a life form, a population is a group of different species, and a community is a single species in the same area.

Variation refers exclusively to visible physical differences between individuals of the same species.

False (B)

What is the primary function of the Basic Local Alignment Search Tool (BLAST)?

To find regions of similarity between biological sequences.

A group of organisms of the same species living in the same area is referred to as a ______.

<p>population</p> Signup and view all the answers

Match the type of variation with its correct description:

<p>Discontinuous Variation = Variation where individuals fall into distinct categories. Continuous Variation = Variation where individuals demonstrate gradation across a range of traits.</p> Signup and view all the answers

Which of the following is NOT a key characteristic of the types of variation?

<p>Variation only occurs at the species level. (B)</p> Signup and view all the answers

A community only includes populations of species that directly interact with each other.

<p>False (B)</p> Signup and view all the answers

Describe how variations are important for each level of biology?

<p>Variations are important for survival of species by allowing populations to adapt and respond to selection pressures.</p> Signup and view all the answers

The differences in the structural, physiological or behavioral characteristics of individuals is described as ______

<p>variation</p> Signup and view all the answers

The NCBI provides

<p>Tools for bioinformatics research (C)</p> Signup and view all the answers

According to the biological species concept, which criterion is essential for defining a species?

<p>Successfully interbreeding and producing fertile offspring. (C)</p> Signup and view all the answers

The biological species concept is universally applicable to all organisms, including those that reproduce asexually.

<p>False (B)</p> Signup and view all the answers

What is a primary limitation of the biological species concept when classifying bacteria?

<p>Horizontal gene transfer</p> Signup and view all the answers

The biological species concept defines species based on their ability to __________ and produce fertile offspring.

<p>interbreed</p> Signup and view all the answers

Why is the biological species concept difficult to apply to extinct organisms?

<p>It's impossible to observe their reproductive behavior. (A)</p> Signup and view all the answers

The biological species concept can reliably differentiate species that have diverged solely through cultural evolution, such as learned behaviors.

<p>False (B)</p> Signup and view all the answers

Give an example of a situation where the biological species concept is difficult to apply due to hybridization.

<p>Hybrid Zones</p> Signup and view all the answers

The existence of __________ gene transfer complicates the application of the biological species concept to prokaryotes.

<p>horizontal</p> Signup and view all the answers

Which of the below best describes the biggest problem of the biological species concept?

<p>It does not account for species that reproduce asexually. (D)</p> Signup and view all the answers

The biological species concept is primarily based on genetic similarity rather than reproductive compatibility.

<p>False (B)</p> Signup and view all the answers

Which scenario most accurately exemplifies the challenge that 'enormous morphological variation' presents to traditional species definitions?

<p>Two groups of <em>Canis lupus</em> that, despite significant size and coat variations, can interbreed and produce fertile offspring. (A)</p> Signup and view all the answers

The ability to perform bacterial conjugation is a key morphological trait used to classify bacteria into distinct species.

<p>False (B)</p> Signup and view all the answers

Explain how 'showing off offspring' relates to species definitions.

<p>Producing fertile offspring is a key criterion in many species definitions.</p> Signup and view all the answers

The presence of fertile offspring suggests that two organisms are members of the same species, ______ other differences.

<p>despite</p> Signup and view all the answers

Match each category of organisms with the primary challenge it presents to traditional species definitions:

<p>Extinct or fossilized organisms = Limited morphological data; reproductive behavior unknown Organisms whose reproductive patterns are hard to observe naturally = Difficulty in determining natural breeding capabilities <em>Canis lupus</em> (domestic dogs and wolves) = Enormous morphological variation within interbreeding populations</p> Signup and view all the answers

Which of the following factors most significantly contributes to the difficulty in accurately quantifying biodiversity on a global scale?

<p>The inherent complexity and vastness of biological systems, coupled with limited accessibility to remote regions. (B)</p> Signup and view all the answers

The term 'Anthropocene' is universally accepted and formally recognized by the International Commission on Stratigraphy as a distinct geological epoch.

<p>False (B)</p> Signup and view all the answers

Briefly explain the core concept of the 'Anthropocene' and its significance in the context of environmental change.

<p>The Anthropocene proposes that humanity has become a dominant geological force, significantly shaping Earth's environment and climate. It highlights the profound and lasting impact of human activities on the planet.</p> Signup and view all the answers

The increasing rate of species extinctions, largely attributed to human activities, is referred to as ______ extinctions.

<p>anthropogenic</p> Signup and view all the answers

Match the following concepts with their most relevant descriptions:

<p>Anthropocene = A proposed geological epoch defined by human dominance over Earth's environment/climate. Biodiversity Quantification = The process of measuring and assessing the variety of life within a specific area or on a global scale. Anthropogenic Extinctions = Species disappearances primarily caused by human activities.</p> Signup and view all the answers

Which of the following is the most significant challenge in accurately quantifying biodiversity?

<p>Difficulty in monitoring remote and inaccessible habitats (C)</p> Signup and view all the answers

Anthropogenic activities have a negligible impact on present-day extinction rates.

<p>False (B)</p> Signup and view all the answers

Explain why assigning a precise start date to the Anthropocene is contentious among scientists.

<p>Defining a single start date is challenging because human impact has gradually increased over time, and different indicators (e.g., industrial revolution, nuclear testing) yield different dates. There is no singular event that marks a clear beginning.</p> Signup and view all the answers

The ______ refers to the proposed geological epoch characterized by significant human impact on Earth's geology and ecosystems.

<p>Anthropocene</p> Signup and view all the answers

If the natural extinction rate is estimated to be 0.00001% - 0.0001% annually, what is the estimated range of the current extinction rate relative to the natural rate?

<p>1,000 - 10,000 times higher (C)</p> Signup and view all the answers

A loss of biodiversity could potentially limit the scope and pace of scientific advancements by reducing the availability of unique biological resources and insights.

<p>True (A)</p> Signup and view all the answers

Describe how maintaining a high level of biodiversity can positively influence the resilience and adaptability of a population when faced with environmental changes or diseases.

<p>Genetic diversity within a population allows for a greater range of traits, increasing the likelihood that some individuals will possess characteristics that enable them to survive and reproduce under new or challenging conditions.</p> Signup and view all the answers

The current rate of species extinction is estimated to be 1,000 to 10,000 times ______ than the natural extinction rate.

<p>higher</p> Signup and view all the answers

Which of the following is the most direct way that biodiversity contributes to the stability and health of entire environments?

<p>Enhancing the complexity of food webs and ecosystem functions, promoting resilience to disturbances. (C)</p> Signup and view all the answers

Considering the current rate of species extinction, which statement best describes its potential impact on society at large?

<p>It undermines essential ecosystem services and exacerbates global challenges, such as climate change and food security. (D)</p> Signup and view all the answers

Match the following aspects of biodiversity with their respective benefits:

<p>Survival within a Population = Genetic diversity enables adaptation to changing environmental conditions. Whole Environments = Complex ecosystems enhance resilience to disturbances and climate change. Society at Large = Ecosystem services support food security, clean water, and human health. Scientific Advancement = Unique biological resources drive innovation and technological development</p> Signup and view all the answers

Flashcards

Anthropogenic Extinctions

Extinctions caused by human activities.

Anthropocene

Proposed epoch defined by human impact on Earth's environment and climate.

Challenges in Quantifying Biodiversity

quantifying biodiversity is challenging due to the vastness of unexplored habitats, cryptic species, taxonomic challenges, funding shortages, and the constant evolution and adaptation of species

Annual Extinction Rate

The estimated annual extinction rate of species.

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Current vs. Natural Extinction

Current extinction rates are estimated to be 1,000 to 10,000 times higher than natural background rates.

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Biodiversity & Survival

Genetic diversity allows populations to adapt to changing conditions, increasing their chances of survival.

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Biodiversity & Environments

Diverse ecosystems are more resilient and provide essential services like pollination and clean water.

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Biodiversity & Society

Biodiversity supports agriculture, medicine, and tourism, contributing to economic stability and human well-being.

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Biodiversity & Science

Biodiversity provides a vast library of genetic and biological information for scientific research and discovery.

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Biodiversity

The variety of life on Earth at all its levels, from genes to ecosystems, and the ecological and evolutionary processes that sustain it.

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Biological Species Concept

Defines species based on their ability to interbreed and produce viable, fertile offspring.

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Asexual reproduction issues

The biological species concept struggles with organisms that reproduce asexually.

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Horizontal gene transfer issues

The biological species concept has limitations when species exchange genetic material via processes other than reproduction.

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Members Must Breed

Organisms that can successfully interbreed and produce fertile offspring according to the biological species concept.

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Bacterial Conjugation

Transfer of genetic material between bacterial cells by direct cell-to-cell contact.

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Canis lupus

Scientific name for the gray wolf.

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Morphological Variation

Physical differences in traits among individuals of the same species.

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Fertile Offspring

Animals able to breed with each other and produce fertile offspring.

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Enormous

Enormous in size or degree.

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BLAST Analysis

A suite of algorithms used to compare biological sequences, such as DNA or protein sequences, to find regions of similarity.

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Organism

Any individual entity that exhibits the properties of life.

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Population

A group of organisms of the same species living in the same area.

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Community

Populations of two or more different species occupying the same geographical area at the same time.

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Variation

Differences between individuals in a population; can be physiological, structural, or behavioral.

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Discontinuous Variation

Variation where individuals fall into distinct categories with no intermediate values.

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Continuous Variation

Variation where individuals show a range of traits with small differences between them.

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Biological Variation

Differences and diversities at every level of biological organization, from ecosystems to genes.

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Evolution

How genes and traits change within a population over time.

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Ecosystem

Interaction of living organisms with each other and their physical environment.

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Study Notes

  • Biodiversity is the variety of life on Earth at all levels, from genes to ecosystems.
  • Increasing biodiversity is generally considered beneficial for survival within populations, environments, society, and scientific advancement.

Number of Described Species

  • The number of identified and named species in each taxonomic group is currently 2.15 million.
  • Insects: 1.05 million
  • Arachnids: 95,966
  • Crustaceans: 90,820
  • Molluscs: 87,254
  • Fishes: 36,953
  • Reptiles: 12,263
  • Birds: 11,195
  • Amphibians: 8,776
  • Mammals: 6,736
  • Corals: 5,641
  • Many species have not yet been described.

Mass Extinctions

  • Earth has experienced several mass extinction events throughout history:
  • Ordovician-Silurian Extinction: 440 million years ago (MA)
  • Late Devonian Extinction: 365 MA
  • Permian-Triassic Extinction: 252 MA
  • Triassic-Jurassic Extinction
  • Cretaceous-Paleogene Extinction: 66 MA
  • Holocene Extinction: 700 years ago to the present

Threats to Biodiversity

  • Rapid environmental changes threaten biodiversity.
  • Key threats include:
  • Habitat loss
  • Climate Change
  • Pollution
  • Overexploitation
  • Invasive Species
  • Disease
  • Estimated annual species extinction rate is 0.01% to 0.1%, which is 1,000 to 10,000 times higher than natural rates.
  • A significant number of extinctions are anthropogenic (human-caused).
  • The Anthropocene is a proposed geological epoch defined by humanity's dominant role in shaping the Earth.

Quantifying Biodiversity

  • Incomplete knowledge hinders accurate quantification of biodiversity.
  • Identifying and classifying species poses a significant challenge.

Dichotomous Keys

  • Dichotomous key is a tool used to identify organisms based on binary choices between characteristics.
  • They help identify organisms based on a series of choices between two descriptions or characteristics.

Phylogenetic Trees & Cladistics

  • Common terms are used, and misused interchangeably, Evolutionary Tree, Phylogenetic Tree, Cladogram
  • Evolutionary tree shows evolutionary relatedness without quantifying time or change.
  • Phylogenetic tree quantifies time or evolutionary change via branch length, often based on sequence evidence.
  • Cladogram divides organisms into easily distinguishable groups (clades) without a time-scale.
  • It is used to highlight similar characteristics within clades.

Trees: Evolutionary/Phylogenetic Tree/Cladogram

  • Diagrams represent a proposed evolutionary history/relationships between a set of species.
  • The come in a variety of arrangements

Tree Terminology

  • The pattern of branch connections represents our current understanding of evolutionary descent.
  • Terminal branches: Species of interest
  • Root: Shared descendent of all species shown)
  • Nodes: Speciation events
  • MRCA stands for most recent common ancestor.
  • Branches

Cladistics Definition

  • Cladistics is an approach to biological classification where organisms are arranged into clades.
  • Clades are based on hypotheses of most recent common ancestry.
  • Cladistics allows us to predict undiscovered extinct species based on characteristics.
  • Used to re-evaluate the classification system to see what has to change.

Cladistic Terms

  • Clade includes a common ancestor (node) and all of its descendants.
  • Objective evidence for is based on gene or protein sequences.
  • A Sister group is a pair of terminal branches that share a common node
  • An Outgroup is a distantly related group that diverged prior to the clade in question.

DNA-based Classification

  • DNA is a good tool offering differentiating factors such as chromosomal traits.
  • Chromosomes are the number, morphology, and allosome interactions
  • Genes are number shared and sequence similarity
  • Genomes are size and conserved sequences

Chromosomes as a Classification Tool

  • Different organisms have varying numbers of chromosomes.
  • Closely related species unlikely to produce offspring if chromosomes are different.
  • Chromosome morphology also varies.

Genes as a Classification Tool

  • Genes are a sequence of nucleotides that is transcribed to produce RNA, which is then translated into proteins.
  • Similar organisms possess similar genes.

Genomes as a Classification Tool

  • Size varies considerably across kingdoms
  • Virus and bacteria genomes are small
  • Prokaryotic genomes are more similar, and Eukaryota ones are more similar.
  • Plant genomes vary dramatically in size due to polyploidy.

NCBI

  • U.S. National Institute of Health (NIH) owns & operates the National Centre for Biotechnology Information (NCBI)
  • NCBI maintains a huge database of:
    • nucleotide (DNA & RNA) sequences
    • protein sequences
    • biotech tools
  • NCBI and related tools are used to help determine relatedness.

Definitions to include with Types of Variation & Species Concepts

  • Organism: Any biological system that functions as an individual life form
  • Population: A group of organisms of the same species in the same area.
  • Community: Populations of two or more different species occupying the same geographical area at the same time
  • Variation: is the physiological, structural or behavioural differences between individuals

Variations

  • Discontinuous (AKA Discrete) Variation- distinct classes or categories exist characteristics can not measured, individuals do not have characteristics between specific categories.
  • Continuous Variation- no distinct classes, measured, falls within a range, between two extremes.
  • Intraspecific variation is the variation within a single species: inheritable meiosis, sexual reproduction, mutation and gene flow
  • Interspecific variation is variation between the individuals, as between two or more species, species have more similar variations but the higher the taxonomy the larger the variation.

Speciation

  • Formation of the new and distinct species as a result of evolution
  • Traits in a population can become more diverse or different
  • Use caution to establish when an organism becomes a new one

Many Species Concepts

  • Morphological- members are based on definitive features qualitatively or quantitatively
  • Biological- Members can produce fertile offspring from each other

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Explore the relationships between organisms, populations, and communities and the concept of variation within species. Learn about the function of BLAST and the characteristics that define biological species according to the biological species concept.

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