Biodiversity and Taxonomy Quiz

Biodiversity

• Decreasing biodiversity has detrimental effects on food supplies, medicines, tourism, and ecosystems, disrupting crucial biogeochemical cycles.
• Maintaining biodiversity supports the health and sustainability of ecosystems.
• Habitat fragmentation, pollution, and climate change contribute to a rapid decline in biodiversity.
• Species extinction (approximately 27,000 per year) is a natural process, but human activities are driving a mass extinction event.
• Biodiversity encompasses the variety and number of species on Earth.
• Scientists have identified and described about 1.8 million species, with estimates suggesting up to 15 million.

Taxonomy and Classification

• Taxonomy is the branch of biology focusing on identifying and classifying organisms.
• Carolus Linnaeus is considered the "Father of Modern Taxonomy," developing a system for classifying species based on shared physical characteristics.
• Binomial nomenclature assigns each species a two-part name consisting of a genus name (capitalized) and a species name (lowercase). (Example: Felis silvestris)
• The order of taxonomic classification (most to least inclusive) is Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species. ("Did King Philip Come Over From Germany Swimming?")
• Taxonomic lists help determine relatedness, similarities, and differences between organisms.
• Dichotomous keys classify unknown organisms based on observable characteristics.

Phylogeny

• Phylogeny studies the evolutionary relationships among different groups of organisms.
• Evidence for phylogeny includes similar stages of embryonic development, homologous structures (anatomical similarities with different functions), and genetic similarities (genetically similar organisms more likely share a common ancestor.)
• Phylogenetic trees are diagrams showing evolutionary relationships among species.
• Branch tips represent descendant taxa.
• Internal nodes represent common ancestors.
• Edges/branches represent the evolutionary timeline.
• The root represents the most recent common ancestor.
• Sister groups are two taxa that split from the same node.
• A clade includes a common ancestor and all of its descendants.

Prokaryotes vs. Eukaryotes

• Prokaryotic cells lack membrane-bound organelles and are characterized by organisms like Eubacteria and Archaea.
• Eukaryotic cells contain membrane-bound organelles and include organisms in the Eukarya domain (Protista, Fungi, Plantae, and Animalia).
• Eubacteria are diverse, widespread, and can be beneficial or harmful to humans.
• Archaea are "ancient bacteria" often found in extreme environments.
• Eubacteria, Archaea, and Eukarya are the three domains of life.

Bacteria

• Bacteria are classified by shape and arrangement (coccus, bacillus, spirillum).
• Arrangements include diplo-, strepto-, and staphylo- forms.
• Bacteria primarily reproduce asexually through binary fission, and some can reproduce sexually via conjugation.
• Bacteria can be autotrophic or heterotrophic.

Protists

• Protists are a diverse group of eukaryotic organisms.
• Some protists are unicellular, while others are multicellular.
• Protists can be autotrophic or heterotrophic and move using cilia, flagella, or pseudopods, and can reproduce asexually through binary fission or sexually through conjugation.
• Infolding was a key process leading to the development of membrane-bound organelles in eukaryotes.
• Endosymbiosis explains how mitochondria and chloroplasts developed in eukaryotes.

Viruses

• Viruses are non-living, infectious particles containing genetic material (DNA or RNA) within a protein capsid.
• Viruses are categorized by shape, genetic material, size, and the type of cell they infect.
• Viruses cannot replicate on their own and become active when their genetic material enters and controls a living cell.
• The lytic cycle involves viral invasion, replication, assembly, new virus release, and host cell destruction.
• The lysogenic cycle involves viral DNA integration into the host DNA, with viral replication only occurring when triggered by certain stimuli.
• Some viruses have an envelope derived from the host cell membrane.

Classification of Kingdoms

• The six kingdoms of life are Eubacteria, Archaea, Protista, Fungi, Plantae, and Animalia.
• These kingdoms are organized within the three domains: Eubacteria, Archaea, and Eukarya.
• Sources provide charts summarizing the type, number, structure, nutrition, and reproduction modes of each kingdom.

DNA Structure and Function

• DNA, deoxyribonucleic acid, is the fundamental hereditary material.
• Chromosomes are tightly packed chromatin containing genes.
• Genes are DNA segments encoding protein production and traits.
• Nucleotides are the building blocks of DNA, comprising a phosphate, deoxyribose sugar, and a nitrogenous base.
• DNA has a double-helix structure with complementary base pairing (A-T, G-C).

Chromosomes and Cell Division

• Haploid cells have one set of chromosomes, while diploid cells have two sets.
• Autosomes are non-sex chromosomes, and allosomes are sex chromosomes.
• Mitosis produces two identical daughter cells for growth and repair.
• The four stages of mitosis are prophase, metaphase, anaphase, and telophase.
• Cytokinesis follows mitosis, dividing the cytoplasm.
• Meiosis produces four genetically unique haploid gametes.
• Meiosis I includes Prophase I, Metaphase I, Anaphase I, and Telophase I. Homologous chromosomes pair up to form tetrads, and crossing over can occur.
• Meiosis II produces genetically unique haploid cells.
• Non-disjunction during meiosis can result in abnormal chromosome numbers.
• Karyotypes are visual representations of an organism's chromosomes used to identify abnormalities.
• Aneuploidy describes possessing an abnormal number of chromosomes (e.g., monosomy, trisomy).
• Polyploidy represents having more than two chromosome sets.

Theories of Evolution

• Lamarck's theory proposed the inheritance of acquired characteristics.
• Darwin's theory of evolution (Darwin-Wallace theory) proposes that species evolve via natural selection.
• Natural selection favors individuals with beneficial variations, increasing their survival and reproduction rates.
• Alfred Russel Wallace independently developed a similar theory of evolution.
• Charles Darwin's observations, particularly in the Galapagos Islands, led to his theories.
• Fitness refers to an organism's ability to survive, reproduce, and pass on traits to its offspring.
• The fossil record is evidence of life's history and shows species changing and going extinct.

Mechanisms of Evolution

• Genetic drift is random change in allele frequencies.
• Gene flow involves the movement of genes between populations.
• Mutations introduce new genetic variations.
• Sexual selection favors traits that increase mating success.
• Artificial selection involves human-directed breeding for specific traits.
• Natural selection favors traits that increase survival and reproduction in a particular environment.

Speciation

• Speciation is the process of forming new species.
• Allopatric speciation occurs when populations are geographically separated.
• Sympatric speciation occurs when populations become reproductively isolated without geographic separation.

Adaptations

• Adaptations are characteristics that enhance survival and reproduction in a specific environment.
• Structural adaptations involve physical features.
• Physiological adaptations involve chemical processes.
• Behavioral adaptations are actions taken to respond to the environment.
• Mimicry is when one species resembles another.

Digestive System

• The alimentary canal processes food through the mouth, pharynx, esophagus, stomach, small intestine, and large intestine.
• Accessory organs (salivary glands, liver, gallbladder, and pancreas) aid in digestion.
• Peristalsis is muscle contraction moving food.
• Macromolecules are broken down to smaller components.
• Carbohydrates are broken into monosaccharides.
• Proteins are broken into amino acids.
• Fats are broken into fatty acids and glycerol.
• Enzymes speed up chemical reactions.
• Nutrients are absorbed, with capillaries absorbing most digested nutrients and lacteals absorbing lipids.
• Insulin lowers blood glucose.
• Glucagon raises blood glucose.

Respiratory System

• The respiratory system facilitates gas exchange.
• The trachea, bronchi, bronchioles, and alveoli are key structures.
• Cilia and mucus filter the air.
• Breathing involves inhalation and exhalation, diaphragm movement, and intercostal muscle contraction.
• Respiration rate is controlled by carbon dioxide concentration.

Circulatory System

• The circulatory system transports blood and various substances throughout the body.
• Arteries carry oxygenated blood away from the heart, while veins carry deoxygenated blood back to the heart.
• Capillaries exchange gases, nutrients, and wastes.
• Hemoglobin carries oxygen.
• The pulmonary and systemic circuits are two divisions.
• Blood pressure measures the force of blood against vessel walls with systole as contraction and diastole as relaxation.