Chapter 24: Speciation in Biological Science

Speciation

Creation of distinct species from an ancestral species.

Gene flow

Movement of alleles between populations.

Genetic isolation

Barrier preventing gene flow between populations.

Genetic divergence

Evolutionary changes in isolated populations.

Mutation

Random changes in DNA sequence.

Natural selection

Differential survival and reproduction based on traits.

Genetic drift

Random changes in allele frequencies over time.

Allele frequencies

Proportion of different alleles in a population.

Divergence

Process where populations evolve independently.

Species

Evolutionarily independent population or group of populations.

Biological Species Concept

Identifies species based on reproductive isolation.

Reproductive Isolation

Prevents gene flow between populations.

Prezygotic Isolation

Prevents mating between different species.

Postzygotic Isolation

Hybrid offspring fail to survive or reproduce.

Morphospecies Concept

Defines species by morphological differences.

Morphological Features

Size, shape, or other physical characteristics.

Polymorphic Species

One species appearing as multiple due to variation.

Cryptic Species

Species that differ in non-morphological traits.

Phylogenetic Species Concept

Identifies species based on evolutionary history.

Monophyletic Group

Ancestral population and all its descendants.

Synapomorphies

Unique traits shared by a common ancestor.

DNA Sequence Data

Used to identify synapomorphies in species.

Independent Evolution

Species evolve separately due to lack of gene flow.

Phylogenies

Evolutionary trees representing relationships among species.

Species Diversity

Variety of species recognized by different concepts.

Fossil Species

Species identified from fossil records.

Asexual Species

Species that reproduce without sexual reproduction.

Geographical Overlap

Necessary for evaluating reproductive isolation.

Disadvantages of Biological Concept

Not applicable to fossils or asexual species.

Application of Species Concepts

Researchers use all three concepts in practice.

Elephant Species Example

Illustrates application of species concepts in nature.

Systematics

Biology discipline classifying organism relationships.

Taxonomy

Describing, naming, and classifying species.

Taxonomist

Scientist answering species classification questions.

Species

Basic unit of biological classification.

Morphological comparisons

Analyzing physical traits to distinguish species.

Biological species concept

Species defined by interbreeding capability.

Morphospecies concept

Species defined by anatomical similarities.

Phylogenetic species concept

Species defined by genetic relationships.

Genetic isolation

Separation of populations due to geography.

Allopatry

Populations living in different geographic areas.

Allopatric speciation

Speciation due to geographic isolation.

Dispersal

Movement of individuals to new locations.

Vicariance

Physical barrier splits a population.

Biogeography

Study of species distribution across geography.

Colonization events

Initial population establishment in a new area.

Speciation

Formation of new and distinct species.

Hybrid offspring

Offspring from interbreeding different species.

Monophyletic group

Group consisting of a common ancestor and descendants.

Savanna elephants

Larger eared elephants from Africa.

Forest elephants

Smaller eared elephants from Central Africa.

Three-species hypothesis

Theory proposing three distinct elephant species.

Allopatric Speciation

Speciation due to geographic separation of populations.

Genetic Drift

Random changes in allele frequencies in populations.

Natural Selection

Process favoring advantageous traits for survival.

Vicariance

Speciation caused by physical barriers splitting populations.

Sympatric Speciation

Speciation occurring within the same geographic area.

Disruptive Selection

Selection favoring extreme traits over intermediate traits.

Ecological Niche

Range of resources and conditions a species uses.

Killer Whale Ecotypes

Different groups of killer whales with distinct traits.

Resident Group

Larger, stable groups of killer whales.

Transient Group

Smaller, traveling groups of killer whales.

Mate Choice

Selection of partners based on specific traits.

Chromosomal Mutations

Genetic changes affecting chromosome structure or number.

Dorsal Fin Shape

Characteristic used to identify killer whale individuals.

Saddle Patches

Distinct markings on killer whales' backs.

Feeding Cultures

Behavioral differences in hunting and eating among ecotypes.

mFAS Gene

Gene influencing mate choice in fruit flies.

Ecological Selection

Survival based on adaptation to environmental conditions.

Gene Flow

Transfer of alleles between populations through migration.

Isolation Mechanisms

Factors preventing interbreeding between populations.

Divergence

Process where populations evolve different traits.

Behavioral Isolation

Differences in mating behaviors preventing interbreeding.

Environmental Adaptation

Changes in traits to better suit the environment.

Ancestral Population

Original population from which species diverge.

Killer Whale Ecotypes

Distinct groups based on behavior and morphology.

Resident Killer Whales

Larger groups with stable feeding habits.

Transient Killer Whales

Smaller groups with different hunting strategies.

Chromosomal Mutations

Genetic changes that can initiate speciation.

Gene Flow

Transfer of alleles between populations.

Dorsal Fin Shape

Characteristic used to identify killer whale ecotypes.

Saddle Patches

Unique markings on killer whales for identification.

Ecological Selection

Survival based on environmental adaptations.

Behavioral Isolation

Prevention of mating due to differing behaviors.

Isolation by Distance

Reduced gene flow due to geographic separation.

Niche Differentiation

Process where species adapt to different niches.

Disruptive Selection for Feeding

Selection favoring specific hunting methods in killer whales.

Speciation Evidence

Data supporting mechanisms of species divergence.

Amazon Basin Vicariance

Geological events isolating populations in the Amazon.

Disruptive Selection

Natural selection favoring extreme traits over intermediates.

Prezygotic Isolation

Prevents mating between different species before fertilization.

D. serrata

A species that no longer mates with D. birchii.

Pheromone

Chemical signal used for communication between mates.

Polyploidy

Condition of having more than two chromosome sets.

Autopolyploid

Organism with doubled chromosome number from the same species.

Allopolyploid

Organism with chromosome sets from different species.

Tetraploid

An organism with four sets of chromosomes (4n).

Reproductive Isolation

Inability of different species to produce fertile offspring.

Inbreeding Depression

Reduced fitness due to breeding between closely related individuals.

Heterozygosity

Presence of different alleles at a gene locus.