ibrahim bio notes

Methicillin-resistant Staphylococcus aureus

An infectious bacterium that is difficult to treat with antibiotics.

Staphylococcus aureus

Also known as staph, some strains are harmless while others can cause disease.

MRSA strand

Approximately 2% of the U.S. population carries this drug-resistant strain.

Gene transfer

The process that can spread alleles for antibiotic resistance to other bacteria.

Natural selection

The process by which individuals with certain heritable traits produce more surviving offspring.

Stabilizing selection

A type of natural selection that favors intermediate phenotypes.

Directional selection

A mode of natural selection that acts against extremes and favors one phenotype.

Disruptive selection

Natural selection that favors individuals at both extremes of the phenotypic range.

Founder effect

Random change in allele frequencies that occurs when a small group establishes a new population.

Genetic drift

Random chance events that can lead to changes in allele frequencies in a population.

Microevolution

The change in the gene pool from one generation to the next.

Bottleneck effect

A loss of genetic diversity that occurs when a population is greatly reduced.

Gene flow

The movement of individuals or gametes/spores between populations that can alter allele frequencies.

Inbreeding depression

Negative reproductive consequences associated with high frequency of harmful recessive alleles.

Adaptive radiation

The rapid evolution of multiple new forms from a common ancestor, often due to environmental changes.

Hominins

Modern humans and their extinct relatives.

Hominids

All hominins plus gorillas, orangutans, and other monkeys.

Bipedalism

The ability to walk upright, a characteristic of early hominins.

Phylogenetic tree

A diagram that shows the evolutionary relationships among various biological species.

Mitochondrial DNA (mtDNA)

DNA inherited solely from the mother, used to track human ancestry.

Skin tone

Refers to levels of melanin produced by skin cells, correlating to geography.

Folate

A nutrient destroyed by UV light, essential for proper development.

Vitamin D

A nutrient produced when skin is exposed to UV light, necessary for immune health.

Clumped distribution

A population distribution pattern where resources are unevenly distributed.

Logistic growth

Population growth that starts fast and levels off due to environmental limits.

Carrying capacity

The maximum number of individuals an environment can support based on resources.

Ecology

The study of interactions among organisms and between organisms and their environment.

Ecosystem

All living organisms in an area and their interactions with nonliving parts of the environment.

Density-independent factors

Factors affecting population size regardless of population density, e.g., weather.

Density-dependent factors

Factors affecting population size that depend on the number of individuals in the population.

Keystone species

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

Climate

A primary factor that determines the distribution of ecological communities.

Biomes

Large areas characterized by specific plant life, influenced by temperature and precipitation.

Tundra

A biome characterized by low-growing vegetation and a layer of permafrost.

Taiga

A biome with long cold winters, evergreen trees, and short summers.

Temperate deciduous forest

A biome with moderate winters and rainfall, where trees drop their leaves in winter.

Mediterranean biome

A biome with long, hot dry summers and cool, damp winters.

Major macromolecules elements

Six major elements H, C, N, O, S, and P are the building blocks for biological macromolecules.

Macromolecules

Large complex molecules essential for life, including carbohydrates, proteins, lipids, and nucleic acids.

Carbohydrates

Organic compounds made of carbon, hydrogen, and oxygen, serving as a major energy source.

Proteins

Macromolecules made up of amino acids, crucial for building tissues and facilitating biochemical reactions.

Lipids

Hydrophobic molecules that store energy and make up cell membranes.

Nucleic acids

Biopolymers, such as DNA and RNA, that store and transfer genetic information.

DNA (Deoxyribonucleic acid)

The molecule that carries genetic information in living organisms.

RNA (Ribonucleic acid)

A molecule involved in protein synthesis, acting as a messenger between DNA and ribosomes.

Photosynthesis

The process by which green plants convert sunlight into chemical energy stored in glucose.

Cell respiration

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

Homeostasis

The process by which living organisms maintain stable internal conditions despite external changes.

Eutrophication

An over-enrichment of nutrients in water bodies, leading to excessive growth of algae and deterioration of water quality.

Biochemical cycles

Natural processes that recycle nutrients in various chemical forms from the environment to organisms and back.

Succession

The process of change in species structure of an ecological community over time.

Symbiosis

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

Mutualism

A type of symbiosis where both species benefit from the relationship.

Commensalism

A type of symbiosis where one species benefits while the other is neither helped nor harmed.

Parasitism

A type of symbiosis where one species benefits at the expense of the other.

Biogeochemical cycles

Cycles that describe the movement of elements and compounds between living organisms and the environment.

Limiting factor

An environmental factor that restricts the growth, abundance, or distribution of an organism or population.

Population density

The number of individuals per unit area or volume, influencing ecological interactions.

Carrying capacity

The maximum number of individuals an environment can support based on resources.

Ecological niche

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

Trophic levels

Hierarchical levels in an ecosystem, comprising producers, consumers, and decomposers.

Food web

A complex network of feeding relationships among various organisms in an ecosystem.

Invasive species

Non-native species that spread widely and cause harm to the environment, economy, or human health.

Endangered species

Species at risk of extinction due to habitat loss, poaching, or other factors.

Antimicrobial resistance

A phenomenon where microbial pathogens become resistant to antimicrobial treatments.

Ecosystem services

The benefits that natural ecosystems provide to humans, including pollination, water purification, and climate regulation.

Habitat fragmentation

The process by which larger habitats are divided into smaller, isolated patches, affecting species and their interactions.

Trophic cascade

An indirect effect in an ecosystem where changes to one trophic level impact multiple other levels, often through predation.

Ecological succession

The progression of changes in species composition and community structure over time in an ecosystem.

Carrying capacity

The maximum population size that an environment can sustain indefinitely without degrading the environment.

Biomagnification

The process where certain substances, such as heavy metals or toxins, become more concentrated at each trophic level of the food chain.

Ecological footprint

A measure of how much land and water area a human population requires to produce the resources it consumes and to absorb its wastes.

Pioneer species

Species that are the first to colonize previously disrupted or damaged ecosystems, often leading to ecological succession.

Endemic species

Species that are native to and found only within a specific geographical area, often vulnerable to extinction.

Antigenic variation

The process by which pathogens change their surface proteins to evade the host's immune response.

Biological magnification

The increased concentration of toxins in organisms at successively higher levels in a food chain.

Niche differentiation

The process by which competing species evolve to exploit different resources or habitats.

Ecosystem resilience

The capacity of an ecosystem to recover from disturbances or changes.

Primary productivity

The rate at which energy is converted by photosynthetic and chemosynthetic autotrophs to organic substances.

Nitrogen fixation

The conversion of atmospheric nitrogen into a form usable by living organisms, often performed by certain bacteria.