Chapter 24 Vocab Flashcards
Speciation
The origin of new species
Microevolution
Changs confined to a single gene pool
Macroevolution
Refers to evolutionary change above the species level
Biological species concept
Defines a species by a population or group of populations whose members have the potential to interbreed in nature and produce viable offspring but can’t produce viable offspring with other populations
Reproductive isolation
The presence of biological barriers that keep two different species from creating hybrid offspring
Prezygotic barrier
Prohibits mating of different species by preventing fertilization of ova or impedes mating
Postzygotic barrier
Prevents the hybrid offspring from developing into a viable, fertile organism
Habitat isolation
Two species are kept from creating offspring because while they live in the same region, they live in different parts and rarely cross paths
Temporal isolation
Species that breed at different times of day, different seasons, or different years cannot mix gametes
Behavioral isolation
Courtship rituals to attract mates and other behaviors are unique enough to keep even closely related species from mating
Mechanical Isolation
Morphological differences prevent reproduction
Gametic Isolation
Sperm of one species can’t fertilize the other
Reduced hybrid viability
The parent’s genes may hinder its ability to develop
Reduced hybrid fertility
Differences in parent gametes prevent the organism from reproducing, making them sterile
Hybrid breakdown
Some hybrid offspring are not as viable and robust as their parents
Morphological species concept
Characterizes species by body, shape, size, and features
Paleontological species concept
Focuses on morphologically discrete species based solely on fossils
Ecological species concept
Characterizes species based on its role in its environment
Phylogenetic species concept
Defines species by their genetic histories and differences
Allopatric speciation
Gene flow is interrupted when species are broken up into two geographical populations
Sympatric speciation
Speciation takes place in geographically overlapping populations
Polyploidy
Accidents during cell division that result in extra sets of chromosomes
Autopolyploid
An organism that has two chromosomes sets, all originating from a single species
Allopolyploid
Having two or more complete sets of chromosomes derived from different species.
Adaptive radiation
The evolution of many diversely adapted species from a common ancestor upon introduction to new environmental opportunities and challenges
Punctuated equilibrium
Periods of apparent stasis of a species punctuated by sudden change
Exaptations
Structures that evolve in one context and become co-opted for another function
Heterochrony
The evolutionary change in the rate or timing of developmental events
Allometric growth
The proportioning that helps give a body its specific form
Paedomorphosis
Reproductive elements accelerate compared to somatic development, causing the sexually mature age of a species to retain juvenile structures
Homeotic genes
Genes that determine where and how limbs and features are placed and attached
Hox genes
Genes that provide positional information in an embryo
Species selection
The species that endure the longest and generate the most new offspring species determine the direction of major evolutionary trends
