Origin of Species and Macroevolution Concepts

Macroevolution

The study of evolutionary changes that produce new species and groups of species.

Species

A group of related organisms that share a distinctive set of attributes in nature.

Speciation

The process of generating a new species, typically occurs by the accumulation of microevolutionary changes.

Biological Species Concept

Proposed by Ernst Mayr, it defines species based on the ability to interbreed and produce fertile offspring.

Morphological Traits

The physical characteristics of members of a population used to classify them as the same species.

Reproductive Isolation

Prevents one species from successfully interbreeding with another species.

Prezygotic Barriers

Mechanisms that prevent fertilization from occurring.

Postzygotic Barriers

Mechanisms that occur after fertilization, affecting the viability or fertility of the offspring.

Allopatric Speciation

Speciation that occurs when populations are geographically isolated.

Sympatric Speciation

Speciation that occurs without geographic isolation, often through mechanisms like polyploidy.

Geographic Isolation

A key factor in allopatric speciation, where physical barriers separate populations.

Molecular Features

Genetic characteristics used to determine species relationships.

Ecological Factors

Environmental aspects that can influence the classification and identification of species.

Evolutionary Relationships

The connections between species based on their evolutionary history.

Microevolutionary Changes

Small-scale evolutionary changes within a species that can lead to speciation.

Distinctive Attributes

Unique characteristics shared by members of the same species.

Interbreeding Potential

The ability of members of the same species to reproduce and produce fertile offspring.

Asexual Species

Species that reproduce without sexual reproduction, such as bacteria.

Extinct Species

Species that no longer exist and cannot be studied through reproductive isolation.

Stability and Change in Evolution

The overarching history of life characterized by stability, change, lineages arising, and extinction.

Molecular Features

Properties and characteristics used to compare similarities and differences among different populations, including DNA nucleotide sequences of genes, gene order/location along chromosomes, chromosome structure, and chromosome number.

Ecological Factors

Factors related to an organism's habitat that can be used to distinguish one species from another, including food resources and growth conditions.

Evolutionary Relationships

Utilizing evidence like fossils and DNA samples to compare similarities and differences among different populations, suggesting evolutionary relatedness.

Biological Species Concept

A species is defined as a group of individuals whose members have the potential to interbreed in nature to produce viable, fertile offspring, but cannot interbreed with members of other species.

Reproductive Isolation

The existence of biological factors (barriers) that prevent one species from successfully interbreeding with a different species.

Prezygotic Mechanisms

Reproductive isolating mechanisms that prevent the formation of a zygote.

Evolutionary Lineage Concept

Members of a species have shared in an evolutionary process and an evolutionary history.

Ecological Species Concept

Members of a species are adapted to a particular set of resources (niche) in the environment, explaining differences in form and behavior as adaptations to resource availability.

General Lineage Concept

All modern species concepts are variants of a single general concept of species, using species criteria that provide contingent properties and standards for judging whether an entity qualifies as a species.

Drawbacks of Molecular Features

It may be difficult to draw the line when separating groups based on molecular features.

Drawbacks of Ecological Factors

Different groups may display very similar growth characteristics, and even the same species may show great variation in the growth conditions it will tolerate.

Common Ancestor

If two organisms share an evolutionary relationship, it means they have a common ancestor on the evolutionary tree.

Genetic Exchange

A biological species is the largest set of populations in which genetic exchange is possible and that is genetically isolated from other populations.

Morphological Similarities

Similarities and differences used to distinguish different species that may look morphologically similar.

Species Classification Debate

Questions whether organisms are truly divided into discrete units called species or if this classification is an arbitrary attempt to impose order on the natural world.

DNA Sequences

Used as a property to compare similarities and differences among different populations in molecular features.

Chromosome Structure

A characteristic used in molecular features to compare different populations.

Chromosome Number

A property used in molecular features to compare similarities and differences among populations.

Gene Order/Location

A characteristic used in molecular features to compare different populations.

Fossils

Evidence used in evolutionary relationships to compare similarities and differences among populations.

Amino Acid Sequence

A comparison from Chapter 22 related to molecular features.

Postzygotic

Block development of a viable and fertile individual after fertilization has taken place.

Prezygotic Isolating Mechanisms

Five types of mechanisms that impede mating or hinder fertilization.

Habitat isolation

Two species encounter each other rarely, or not at all, because they occupy different habitats.

Temporal isolation

Species reproduce at different times of the day, different seasons, or different years.

Behavioral isolation

Courtship rituals and other behaviors unique to a species act as reproductive barriers.

Mechanical isolation

Morphological differences, such as size or incompatible reproductive organs prevent two species from interbreeding.

Gametic isolation

Two species attempt to interbreed, but the gametes of one species may not be able to fertilize the gametes of the other species.

Postzygotic Isolating Mechanisms

Three types of mechanisms that prevent the hybrid zygote from developing into a viable, fertile adult.

Hybrid inviability

Gamete of one species is fertilized by a gamete from another species, but fertilized egg cannot develop past early embryonic stages.

Hybrid sterility

Hybrid is viable, but sterile (ex. mule).

Hybrid breakdown

Some first-generation hybrids are fertile, but their offspring have genetic abnormalities that are detrimental.

Speciation

The formation of a new species due to the accumulation of genetic changes.

Geographic isolation

Speciation can occur when gene flow is interrupted or reduced due to a population becoming isolated.

Allopatric speciation

Speciation that occurs when a population becomes isolated from other populations.

Founder effect

Isolation can lead to the founder effect, since not all alleles will likely be represented by the new population.

Sympatric speciation

Speciation that takes place in geographically overlapping populations without physical barriers to interbreeding.

Reproductive isolation

Any process that results in reproductive isolation of a portion of a species could lead to speciation.

Chromosome changes

Likely mechanisms for speciation under sympatric conditions.

Nonrandom mating

A likely mechanism for speciation under sympatric conditions.

Microevolution

Small-scale evolutionary changes within a species.

Macroevolution

Large-scale evolutionary changes that occur over long periods.