Ecology Lecture Notes

Flashcards for Ecology Lecture Notes

Sympatric Speciation

Speciation occurs in geographically overlapping populations, leading to genetic divergence and potentially new species.

Reproductive Barriers

Biological barriers that prevent members of different species from producing hybrids, often favored by natural selection against hybrids.

Habitat Isolation

Species occupy different habitats, decreasing the probability of encountering other species.

Temporal Isolation

Species breed at different times of day or year, decreasing the probability of encounter while reproductively active.

Behavioral Isolation

Courtship rituals that are species-specific and not recognized by other species, preventing mating.

Mechanical Isolation

Morphological differences prevent successful mating, such as differences in size or shape.

Gametic Isolation

Sperm and eggs are not compatible, preventing fertilization.

Reduced Hybrid Viability

A hybrid forms, but alleles interact and impede development, resulting in frail offspring that cannot compete.

Reduced Hybrid Fertility

A hybrid forms but is sterile and unable to reproduce.

Hybrid Breakdown

First generation hybrids are viable and fertile, but the second generation is weak and sterile due to the accumulation of recessive alleles.

Genetic Drift and Speciation

Genetic drift, especially due to founder effects, increases divergence among populations, potentially leading to speciation.

Taxonomy

The theory and practice of classifying organisms.

Taxon

A group of organisms treated as a unit for classification.

Linnaean System

A hierarchical classification system where inclusiveness changes with levels (Domain to Species).

Species Name

A two-part name consisting of the genus (capitalized) and species (lowercase), written in italics or underlined.

Phylogenetic Reconstruction

A hypothesis of evolutionary relationships, often represented by a cladogram.

Cladogram

A diagram showing shared derived character states to represent evolutionary relationships.

Character

A heritable feature that varies among individuals (e.g., wing).

Character State

A variant of a character (e.g., present or absent).

Outgroup

A group used for comparison in phylogenetic analysis that possesses all ancestral character states.

Ingroup

The group whose evolutionary relationships are being investigated.

Parsimony

The principle of choosing the phylogeny with the fewest evolutionary events.

Sister Taxa

Groups of organisms that share an immediate common ancestor.

Clade

A group that contains an ancestral species and all of its descendants; a monophyletic group.

Monophyletic Group

An ancestral species and all of its descendants.

Paraphyletic Group

An ancestral species and some, but not all, of its descendants.

Polyphyletic Group

A group that includes distantly related species but not their most recent common ancestor.

Scientific Method

A method of procedure that has characterized natural science since the 17th century, consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses.

Control Group

A group used for comparison to the experimental group in a scientific study.

Replicate

An independent experimental unit used for analysis.

P-value

Probability that the results obtained are due to chance.

Type I error

Rejecting a true null hypothesis (false positive).

Type II error

Failing to reject a false null hypothesis (false negative).

Ecology

The scientific study of the interactions between organisms and their environment.

Levels of Organization in Ecology

Individuals, Population, Community, Ecosystem.

Behavioral Ecology

How animals make decisions that influence survival and reproductive success.

Mating Systems

Monogamy or Polygamy.

Social Monogamy

Relationship appears monogamous, but is not genetically the case

Certainty of Paternity

Higher in species with external fertilization.

Signaler

Sender communicates a message.

Receiver

Recipient of information.

Honest Signal

A true reflection of the quality (of genes); often costly to produce and maintain.

Dishonest Signal

Sender manipulates the response of receiver; purposefully trying to trick individuals.

Agnostic Behavior

A social behavior linked to fighting within a species, including aggressive behavior and submission.

Injury-Related Chemical Cue (IRCC)

Chemicals released into the environment following injury, triggering anti-predatory behavior in conspecifics.

Innate Behavior

A response an organism is born with; developmentally fixed (not learned).

Learned Behavior

Imprinting, Associative and Social Learning.

Altruism

An act that favors another individual at some cost to self; Reciprocal and Kin Selection.

Reciprocal Altruism

Altruistic act to a non-relative that must be reciprocated later.

Kin Selection

Altruistic act that involves relatives with a genetic component.

Population Ecology

The study of populations in relation to their environment.

Population Dispersion

Clumped, Uniform and Random Patterns.

Clumped Dispersion Pattern

Most common b/c resources, social groups, for protection.

Uniform Dispersion Pattern

Equally spaced b/c direct interactions; territoriality.

Random Dispersion Pattern

Unpredictable spacing patterns b/c of abiotic factors.

Population Demography

Study of vital statistics of a population and how they change over time.

Life Table

An age-specific summary of the survival patterns of a population.

Survivorship Curve

A graphical representation depicting the number/proportion of individuals in a cohort still alive at each age; Type I, II & III.

Population Growth

Change in population size over time.

Carrying Capacity

K, the number of individuals of a species that can be supported by the resources within an area.

Exponential Model

J-shaped growth curve: no limits to growth; unlimited resources and no competition (very unrealistic).