Limiting Factors, Genetics, Ecology, and Energetics Review

Vocabulary practice flashcards covering limiting factors, natural selection, DNA gel electrophoresis, niche partitioning, soil nutrient cycles, keystone species, cellular energetics, and ecological pyramids.

Limiting Factor

Something that limits the size, growth, or distribution of a population in an ecosystem, classified into biotic and abiotic categories.

Biotic Limiting Factors

Living elements within an ecosystem that restrict population growth or distribution, such as plants and other animals.

Abiotic Limiting Factors

Non-living physical or chemical factors that limit a population, such as weather, water, and droughts.

Selective Pressure

An environmental factor that affects evolution and drives changes in allele or phenotypic frequencies within a population.

Tusklessness Adaptation

A genetic variation in elephants where individuals are born without tusks; it serves as a favorable survival adaptation in regions with heavy poaching because tuskless elephants are not targeted by humans.

Tuskless Female Frequency by Poaching Level

A distribution showing that areas with heavy poaching have much higher percentages of tuskless females ($33\%$ in offspring aged 10–20 years and $50\%$ in Civil War survivors aged 20+ years) compared to regions with less poaching ($6\%$ across all ages).

Daphne Major Finch Beak Depth Shift

A documented evolutionary response where a drought acted as a selective pressure, favoring finches with larger, deeper, and stronger beaks capable of cracking hard seeds that remained after small, soft seeds became scarce.

DNA Gel Bands

The distinct black lines visible on an electrophoresis gel that represent separated fragments of DNA.

DNA Profiling (Suspect Identification)

The forensic matching of DNA band patterns between evidence and individuals; in this forensic case, Suspect 2 matches the DNA fragments recovered from the crime scene.

DNA Ladder

A standard reference tool that acts as a ruler in gel electrophoresis to estimate the size and number of base pairs of unknown DNA fragments.

Gel Electrophoresis Migration Rate

The physical relationship where longer DNA fragments move more slowly and remain near the starting point, while shorter DNA fragments migrate faster toward the far end of the gel.

Homozygous Marker (Gel Electrophoresis)

A genetic locus represented by a single band on a gel because the individual inherited identical alleles from both parents.

Heterozygous Marker (Gel Electrophoresis)

A genetic locus represented by two separate bands on a gel because the individual inherited two different alleles from their parents.

Ivory DNA Geolocation

The comparison of DNA extracted from seized elephant tusks against reference DNA from known populations to determine geographic origins and prioritize anti-poaching protection.

Niche Partitioning

The process by which competing species partition or divide up resources such as food, space, and time to reduce competition and coexist within the same habitat.

Biodiversity

The variety of species within an ecosystem where each species plays a specific role and organisms rely on one another, making the ecosystem more resilient to disruptions.

Positive Feedback Loop

A cyclic process in which the product or outcome of a reaction causes an amplification or increase in that same reaction.

Soil Nutrient Fixation by Termites

The biological process in which termites in the soil convert nitrogen into a usable form and supply phosphorus, driving a positive feedback loop that promotes plant growth and supports consumers.

Keystone Species

An organism that holds an ecosystem together and upon which many other species depend; if it is removed, the entire ecosystem collapses.

Elephants as a Keystone Species

The ecological role of elephants wherein their nutrient-rich dung germinates seeds and fosters plant growth, providing essential food resources for both producers and consumers.

Mitosis

The process of cell division.

Root Cell Growth Advantage

The faster rate of cell growth in plant roots compared to leaves due to roots directly absorbing growth-limiting soil nutrients like nitrogen and phosphorus.

Photosynthesis

The cellular process carried out by plants inside chloroplasts that uses carbon dioxide as a reactant and yields oxygen as a product.

Cellular Respiration

The metabolic process carried out by plants and all living organisms inside mitochondria that uses oxygen as a reactant and produces carbon dioxide as a product.

Trophic Levels

The sequential feeding steps in an energy pyramid, organized from bottom to top as producers, primary consumers, secondary consumers, and tertiary consumers.

10% Rule

The ecological principle stating that only approximately $10\%$ of the energy stored at one trophic level is transferred to the next higher level.