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Clade

A group of organisms that consists of a common ancestor and all its lineal descendants.

Ecological Niche

The role and space that an organism fills in an ecosystem, including all its interactions with biotic and abiotic factors.

Keystone Species

A plant or animal that plays a unique and crucial role in the way an ecosystem functions.

Carrying Capacity

The size of the population that can be supported indefinitely on the available resources and services of an ecosystem.

Genome

All the genetic material in the chromosomes of an organism, including its genes and DNA sequences.

Gene

Regions of DNA made up of nucleotides; the molecular unit of heredity.

Polygenic Inheritance

When one characteristic is controlled by two or more genes.

Evolution

Change in the genetic composition of a population during successive generations, potentially resulting in new species.

Microevolution

Small-scale variation of allele frequencies within a species or population, where the descendant is of the same taxonomic group as the ancestor.

Macroevolution

Variation of allele frequencies at or above the species level over geological time, resulting in the divergence of taxonomic groups.

Interspecific Hybrid

An example is a mule, which does not produce fertile offspring.

Pioneer Species

Features include the ability to fixate nitrogen, tolerance to extreme conditions, rapid seed germination, and the ability to photosynthesize.

Recombinant DNA Process

Involves isolation of DNA, cutting with restriction enzymes, insertion of DNA fragments, joining with DNA ligase, and amplification through bacterial transformation.

Cladistics Assumptions

Common ancestry, bifurcation, and physical change.

DNA Structure

Composed of deoxyribose sugar, phosphate, and nitrogenous bases with complementary base pairing.

HOX Transcription Factor

A gene family that regulates morphology.

Sex-determining Region Y

A transcription factor gene that regulates cell differentiation.

Speciation and Macroevolution

Occur from an accumulation of microevolutionary changes over time.

Biodiversity

Includes the diversity of species and ecosystems.

Biological Classification

Can be hierarchical and based on different levels of similarity.

Conserved Sequences

Accumulate mutations at a constant rate, aiding in dating divergence.

Noncoding DNA

Many functions are yet to be determined.

Gene Expression Purpose

To synthesize a functional gene product (protein or functional RNA).

Differential Gene Expression

Regulated by transcription factors, it controls cell differentiation for tissue formation.

DNA Sequencing Application

Used to map species’ genomes.

DNA Profiling Application

Identifies unique genetic information.

Evolutionary Radiation

Refers to an increase in taxonomic diversity or morphological disparity.

Natural Selection

Occurs when environmental pressures confer a selective advantage on a specific phenotype.

Mutation

The ultimate source of genetic variation, introducing new alleles to a population.

Chemical Mutagens

Many are carcinogenic and interact directly with DNA.

Eukaryotic DNA

Double-stranded, bound to histones, linear, and contains non-coding DNA.

Prokaryotic DNA

Unbound circular DNA found freely in the cytoplasm, compact, and may contain plasmids.

Linnaean System

Does not rely solely on physical features for classification.

Respiration Inputs

Oxygen and glucose.

Respiration Outputs

Carbon dioxide, water, and ATP.

Photosynthesis Inputs

Carbon dioxide and water.

Photosynthesis Outputs

Oxygen and glucose.

Biotic Limiting Factors

Include competition, predation, and disease.

Abiotic Limiting Factors

Include space, nutrient availability, pollution, and extreme climatic events.

Symbiosis

A close and long-term interaction between two different organisms.

Competitive Exclusion Principle

States that two species competing for the same resources cannot coexist stably.

Keystone Species Role

Maintains community structure and local biodiversity.

Primary Succession

Occurs in areas without initial vegetation.

Secondary Succession

Occurs in areas with existing vegetation.

Helicase Function

Unwinds the DNA double helix and separates strands.

DNA Polymerase Function

Forms new complementary strands and proofreads the DNA.

Genotype

The combination of alleles that an organism has.

Microevolutionary Changes

Can occur through mutation, gene flow, and genetic drift.

Divergent Evolution

Groups from the same ancestor evolve and accumulate differences.

Adaptive Radiation

Rapid diversification of an ancestral population into several ecologically different species.

Convergent Evolution

Independent evolution of similar features in different species.

Parallel Evolution

Similar development of a trait in