Biodiversity and Genetic Diversity Overview

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Questions and Answers

Which of the following best describes the concept of a 'gene pool'?

The total number of different species in an ecosystem.

The number of individual organisms within a given area.

The sum of all the versions of all the genes in a population. (correct)

The variety of habitats available in a specific geographic location.

How does genetic diversity primarily contribute to a population's ability to survive disease?

By preventing any mutations from occurring, thus creating a more stable population.

By decreasing the population size.

By increasing the chance that at least some individuals will have the ability to survive a disease. (correct)

By ensuring that all individuals are identical and therefore equally resistant.

Which statement accurately describes how ecosystem diversity arises?

Ecosystem diversity results from the complex interactions between living and non-living environmental factors. (correct)

Ecosystem diversity is entirely determined by the number of different species in a region.

Ecosystem diversity is primarily a function of the geological history of a given area.

Ecosystem diversity arises solely from the variety of living organisms within an area.

Why is ecosystem diversity vital for organisms including humans?

It provides vital ecosystem services that are essential for survival. Signup and view all the answers

Which of the following is considered an example of an ecosystem service?

Ecotourism. Signup and view all the answers

Which of the following structures is NOT found in all prokaryotic cells?

Flagella Signup and view all the answers

What is the primary function of pili in bacteria?

Exchange of genetic information, including movement and attachment Signup and view all the answers

Which of the following best describes the key difference in cell wall composition between bacteria and archaea?

Bacteria have a cell wall which contains a layer of peptidoglycan, while archaea do not use peptidoglycan. Signup and view all the answers

Which of the following is a unique characteristic of Archaea?

They can inhabit extremely harsh environments. Signup and view all the answers

What does a gram-positive bacterial cell indicate?

It has an outer membrane that absorbs the Gram stain. Signup and view all the answers

What is the main difference between binary fission and conjugation?

Binary fission creates identical daughter cells, while conjugation introduces genetic variation. Signup and view all the answers

How do antibiotics typically work against bacteria?

By interfering with a bacteria's cell processes, cell wall formation and thus reproduction. Signup and view all the answers

Which condition could trigger endospore formation in some bacteria?

Exposure to very high temperatures or nutrient deficiency Signup and view all the answers

What is the central idea of the endosymbiosis theory relative to eukaryotic cells?

The theory suggests how eukaryotic cells evolved by engulfing other cells, forming organelles. Signup and view all the answers

What is a defining characteristic of viruses?

They can only reproduce within a host cell. Signup and view all the answers

Study Notes

Biodiversity

Species Diversity: Refers to the variety and abundance of species within a given area.
Genetic Diversity: Measures the variety of heritable characteristics among interbreeding individuals within a species. This is known as the gene pool, the sum of all gene versions in a population.
Ecosystem Diversity: The variety of ecosystems in the biosphere, encompassing both biotic (living) and abiotic (non-living) components, creating diverse physical and chemical landscapes. Ecosystems provide numerous services.
- Ecosystem Services: Benefits organisms (including humans) receive from sustainable ecosystems, such as habitat for wildlife, ecotourism opportunities, and pest control.

Genetic Diversity

Gene Function: Genes control trait expression and inheritance. Genetic differences cause individual variations.
Resistance to Disease: Genetic diversity within a population increases its ability to survive environmental changes, including disease outbreaks. If all individuals lack resistance, the entire population could be wiped out.
Conservation Biology: Understanding genetic diversity helps conservation efforts by aiding struggling populations.

Prokaryotes (Bacteria and Archaea)

General Characteristics: Single-celled, small (less than 2 micrometers), lack membrane-bound organelles. Organelles are not enclosed by membranes.
Structure:
- Cell Wall: Provides structural support and protection; made of peptidoglycan (bacteria) or other materials (archaea).
- DNA: Forms a circular plasmid, much smaller than eukaryotic DNA.
- Capsule: Allows prokaryotes to attach to surfaces and protects them from immune system attack; prevents dehydration.
- Cell Membrane: Controls substance movement in and out of the cell.
- Nucleoid Region: Contains DNA, RNA, and associated regions.
- Pili: Hair-like structures on the cell surface with various functions (genetic exchange, movement, attachment).
- Flagellum (some bacteria): Tail-like structure used for movement.
- Cilia (some bacteria): Projections used for movement.

Differences Between Bacteria and Archaea

Cell Wall and Membrane: Bacteria cell membranes have a phospholipid bilayer, and cell walls have peptidoglycan. Archaea cell wall and membrane structures differ significantly and resemble more closely those of eukaryotes.
Extreme Environments: Archaea are often found in extreme environments (e.g., high temperatures, high salinity).
Methanogens: A type of archaea that produce methane as a byproduct in oxygen-free environments.
Mutualistic Relationships: Some archaea have mutualistic relationships with other organisms (ex: some help with digestion).
Metabolic Diversity: Bacteria exhibit various types of metabolism, respiration and other cell function variations based on their characteristics of cell wall, movement, and metabolism.
- Gram Stain: Classification of bacteria based on their reaction to a dye (crystal violet and iodine). Gram-positive bacteria absorb the stain; gram-negative bacteria don't. Gram-negative bacteria are often more pathogenic (disease-causing).

Bacterial Reproduction

Binary Fission: Asexual reproduction where a cell replicates its DNA and divides into two identical daughter cells; rapid reproduction rate (e.g., every 20 minutes).
Conjugation: Transfer of genetic material between bacterial cells via a pilus, increasing genetic diversity. This often involves exchanging plasmids.
Endospore Formation: Some bacteria form endospores to protect their DNA from environmental stressors (e.g., high temperature, lack of nutrients). Endospores can remain dormant for long periods and then germinate into active bacteria.

Antibiotic Resistance

Mechanism: Antibiotics disrupt bacterial cell wall formation, metabolic processes, or reproduction.
Development: Mutations in bacteria can lead to antibiotic resistance, which is often transferred via conjugation, increasing quickly in a population because of the reproduction rate.

Viruses

Definition: Non-living, non-cellular infectious agents. They depend entirely on a host cell to carry out their life cycle functions (replication, metabolism).
Size: Extremely small (less than 0.1 micrometers in diameter).
Structure: Contain genetic material (DNA or RNA) surrounded by a protein coat.

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Description

This quiz explores the concepts of biodiversity, species diversity, genetic diversity, and ecosystem diversity. It also delves into the importance of genetic variation in populations and its impact on resilience against disease and environmental changes. Test your understanding of these critical ecological concepts!