Biology Chapter on Respiration and Speciation

SBI 3U Exam Review - Diversity Unit

• Binomial Nomenclature: The scientific name uses the genus name (capitalized) and species name (lower case). Scientific names are italicized when typed, and underlined when handwritten.

Species Concepts

• Morphological Species Concept: Defines species based on physical characteristics like shape, size, and other structural features. Advantages include being simple and easily applicable to many organisms, particularly plants. Disadvantages include difficulties in defining variations among diverse individuals.

• Biological Species Concept: Defines species based on whether two organisms can produce fertile offspring. Advantages include its broad use in science. Disadvantages include difficulties with applying the concept to populations that are geographically separated, asexually reproducing organisms, and fossils.

• Phylogenetic Species Concept: Defines species based on evolutionary history (phylogeny). Advantages include its applicability to extinct species, use of DNA analysis, and help in identifying new species. Disadvantages include the difficulty of obtaining evolutionary histories for all species.

Taxonomic Categories

• Hierarchy of Rank: Organisms are categorized into a hierarchical system, from Domain to Species (e.g., Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species). (KP COFGS)

• Dichotomous Key: A system that helps narrow down the identification of an unknown species one step at a time. It uses a series of either/or questions (e.g., Does it have fur?).

Prokaryotes vs. Eukaryotes

• Prokaryotes (Bacteria and Archaea): Smaller in size with circular DNA not bound by a membrane, single chromosome, mostly asexual reproduction, lack membrane-bound organelles, and generally anaerobic metabolism.

• Eukaryotes (Protists, Plants, Fungi, and Animals): Larger in size with DNA enclosed in a nucleus, multiple chromosomes, mostly sexual reproduction, presence of membrane-bound organelles, and most are aerobic metabolism.

Viruses

• Lytic Cycle: Viruses quickly replicate, assemble new viral particles and release them, killing host cell in the process.
• Lysogenic Cycle: Viruses incorporate their DNA into the host chromosome and remain dormant.

Organisms in Extreme and Moderate Habitats

• Mesophiles: Organisms that live in moderate, less extreme habitats
• Extremophiles: Organisms that live in extreme environments

Cell Division

• Binary Fission: A type of asexual reproduction in prokaryotes. The cell copies its DNA, and elongates, then splits into two identical daughter cells.
• Conjugation: A form of sexual reproduction in prokaryotes, where one cell links to another and transfers part (or all) of its chromosomal content through plasmids.

Animal Diversity

• Invertebrates: Animals without backbones.
• Vertebrates: Animals with backbones.

Multicellular Diversity

• Animals are eukaryotic, multicellular organisms that are heterotrophs
• Animals typically ingest and digest food. They generally exhibit mobility and reproduce sexually.

Genetics

• Karyotype: A photograph of the pairs of homologous chromosomes in a cell.
• Disorders: Can be identified using karyotype analysis (e.g., Trisomy 21, Trisomy 18, Trisomy 13).

Cell Division and Reproduction

• Mitosis: Cell division that produces two identical daughter cells (used for growth and repair).
• Meiosis: Cell division to produce gametes (egg and sperm), involved in sexual reproduction.
• Genetic Crosses: Different types of genetic crosses involve monohybrid and dihybrid crosses, involving one or more traits.

Complex Inheritance Patterns

• Incomplete dominance results in an intermediate phenotype (e.g. pink flowers from red and white parent plants)
• Codominance is when both alleles are fully expressed in the heterozygote (e.g., roan cow with red and white hairs).
• Sex-linked traits are carried on the sex chromosomes.

Evolution

• Adaptation: A trait or structure that increases an organism's survival and reproductive success in a given environment.
• Mimicry: An adaptation in which a harmless species resembles a harmful species in coloration or structure. Batesian mimics share signals with dangerous models.
• Mutations: A permanent change in genetic material; the only source of new genetic variation. Mutagens such as UV radiation can increase mutation rates.
• Natural Selection: Changes in allele frequencies within a population caused by the environment selecting for specific traits, aiding in survival and reproduction.
• Artificial Selection: Selective pressure exerted by humans to improve or modify desirable traits in populations
• Evolutionary Factors: Factors (e.g., gene flow, nonrandom mating, genetic drift, natural selection) that can cause changes in allele frequencies of a population over time.

Molecular Biology

• DNA Barcoding: A technique to determine the evolutionary relationships between species by comparing similarities in their DNA sequences.
• Differences in DNA Sequences: if two species share similar DNA sequences, this indicates they inherited these DNA sequences from a common ancestor

Plant Unit

• Monocots vs. Dicots: Monocots are plants that possess one cotyledon, flower parts in multiples or threes, and usually have parallel veins. Dicots typically have two cotyledons, flower parts in multiples or fours/fives, and have reticulated leaf venation.

Digestive System

• Enzymes: Biological catalysts that speed up chemical reactions. Examples include salivary amylase (mouth), pepsin (stomach), trypsin and chymotrypsin (small intestine).
• Digestion: Includes physical breakdown of food and chemical breakdown by enzymes. The digestive system breaks down carbohydrates, proteins, and fats into smaller molecules, absorbed by the intestinal wall.

Respiratory System

• Lung function: Involves the intake of oxygen from the external environment into the blood, and the expulsion of carbon dioxide.
• Gas exchange: Occurs in the lungs, where oxygen diffuses into the blood and carbon dioxide diffuses out of the blood.
• COPD: Chronic Obstructive Pulmonary Disease - a chronic lung disease that causes difficulty breathing.

Circulatory System

• Heart Anatomy: The heart has four chambers (two atria, two ventricles) and valves. Electrical impulses move blood through the heart effectively.
• Blood Vessels: Arteries carry the blood away from the heart, veins carry it towards the heart; and capillaries facilitate the exchange of nutrients and gases in the system.
• Disorders: High Blood Pressure (hypertension) and Arteriosclerosis (hardening of arteries due to plaque buildup)