Biodiversity, Evolution, and Speciation Concepts

Causation

Indicates a direct cause-and-effect relationship where one event impacts another event.

Correlation

Indicates a statistical relationship between two variables but does not imply causation.

Establishing Causation

Done through experimental studies (e.g., randomized controlled trials) and longitudinal studies by manipulating variables and observing effects over time.

Observational Studies

Show correlation but not causation.

Cross-sectional Studies

Show correlation but not causation.

Biodiversity

The variety of life forms in an ecosystem, including species diversity, genetic diversity, and ecosystem diversity.

Species Richness

The number of different species in a given area.

Species Evenness

Refers to how evenly individuals are distributed among species.

Genetic Diversity

The variation in genetic traits within a species.

Current Trends in Biodiversity

Declining globally due to habitat loss, climate change, pollution, and overexploitation.

Insects

Taxonomic group with the highest number of named species.

Plants

Taxonomic group highly diverse in terms of species.

Amphibians

Taxonomic group with many critically endangered species.

Coral Reefs

Taxonomic group with heavily threatened species.

Invertebrates

Group with many species lacking detailed information, especially in remote or less-studied regions.

Ecosystem Stability

One of the values of biodiversity, where diverse ecosystems are more resilient to disturbances.

Provisioning Services

Products obtained from ecosystems, such as food and water.

Regulating Services

Benefits from ecosystem processes, like climate regulation.

Cultural Services

Non-material benefits from ecosystems, such as recreation and spiritual value.

Supporting Services

Services necessary for the production of all other ecosystem services, like nutrient cycling.

Anthropocene

A proposed geological epoch marked by significant human impact on Earth's geology and ecosystems.

Protected Areas

Conservation strategy involving the establishment of national parks.

Restoration Ecology

Conservation strategy focused on restoring degraded habitats.

Sustainable Use

Conservation strategy involving managing resources to prevent overexploitation.

Captive Breeding

Conservation strategy of breeding endangered species in captivity.

Legislation

Conservation strategy involving enforcing laws to protect species.

Gene Transfer

Movement of genes between organisms.

Determining Fitness

Evaluate the reproductive success and survival of individuals with different traits.

Adaptations

Traits that enhance an organism's fitness.

Mutations and Trait Variation

Mutations create genetic variation, but are rare and random.

Mutation

Ultimate source of new genetic variation.

Genetic Recombination

Shuffles existing genetic variation.

Natural Selection

Evolution does not always result in "better" organisms, just more adapted to the environment.

Natural Selection Graphs

Analyze changes in trait distributions, similar to Galápagos finch beak size examples.

Diploid

Cells with two sets of chromosomes.

Genes

Units of heredity.

Alleles

Different forms of a gene.

Locus

Specific position of a gene on a chromosome.

Genotype

Genetic makeup.

Heterozygote

Individual with two different alleles for a gene.

Homozygote

Individual with two identical alleles for a gene.

Phenotype

Observable traits.

Discrete Traits

Traits controlled by a single gene.

Complete Dominance

Dominant allele masks the recessive allele.

Incomplete Dominance

Heterozygous phenotype is intermediate.

Codominance

Both alleles are expressed equally.

Multiple Alleles

More than two allele forms for a gene.

Sex-linked Traits

Traits located on sex chromosomes.

Polygenic Traits

Traits influenced by multiple genes.

Continuous Variation

Range of phenotypes.

Evolution

Change in allele frequencies.

Gene Pool

All alleles in a population.

Population Genetics

Study of allele frequencies and their changes.

Hardy-Weinberg Equilibrium

State where allele frequencies remain constant.

Phenotypic Frequency

Proportion of individuals with a particular phenotype.

Genotypic Frequency

Proportion of individuals with a particular genotype.

Allele Frequency

Proportion of a particular allele in a population.

Allelic Frequency

Proportion of each allele in the gene pool.

No Mutation

Genetic changes do not occur.

Random Mating

Individuals mate randomly.

No Gene Flow

No movement of alleles between populations.

Large Population Size

No genetic drift.

No Natural Selection

All traits have equal fitness.

Gene Flow

Increases genetic diversity.

Genetic Drift

Random changes in allele frequencies, more pronounced in small populations.

Selection

Non-random changes favor certain traits.

Microevolution

Small-scale evolutionary changes within a species.

Macroevolution

Large-scale changes leading to the formation of new species.

Speciation

Formation of new species.

Species

A group of organisms that can interbreed and produce fertile offspring.

Reproductive Isolation

Mechanisms that prevent different species from interbreeding.

Allopatric Speciation

Speciation occurring due to geographic isolation.

Sympatric Speciation

Speciation occurring within the same geographic area.

Vicariance

Physical barrier divides a population.

Founder Effect

Loss of genetic variation when a new population is established by a small group.

Bottleneck Effect

Dramatic reduction in population size leading to reduced genetic diversity.

Allele Fixation

Alleles become fixed or lost in a population due to genetic drift.

Neutral Mutation

Mutations that do not affect fitness and are subject to drift.

Adaptation

Gene flow can introduce new adaptive traits or dilute advantageous traits.

Advantageous Mutation

Increases fitness.

Deleterious Mutation

Decreases fitness.

Context Dependent

The effect of a mutation depends on the environment.

Inbreeding

Mating between closely related individuals.

Inbreeding Depression

Reduced fitness due to increased homozygosity.

Non-random Mating Effects

Can reduce genetic diversity by increasing the proportion of homozygous individuals.

Drift

Randomly affects allele frequencies, reducing diversity.

Reinforcement

Strengthening of reproductive barriers.

Secondary Contact

Reintroduction of previously separated populations.

Hybrid/Hybridization

Offspring resulting from interbreeding between different species.

Prezygotic Isolation

Mechanisms preventing mating or fertilization.

Postzygotic Isolation

Mechanisms preventing hybrid offspring from developing into viable adults.

Morphospecies Concept

Species defined by physical characteristics.

Biological Species Concept

Species defined by reproductive isolation.