Podcast
Questions and Answers
A biologist discovers two groups of organisms that appear morphologically identical but cannot produce viable, fertile offspring together. Which species concept best explains this observation?
A biologist discovers two groups of organisms that appear morphologically identical but cannot produce viable, fertile offspring together. Which species concept best explains this observation?
- Ecological Species Concept
- Phylogenetic Species Concept
- Biological Species Concept (correct)
- Morphological Species Concept
Which of the following scenarios best illustrates the concept of ecological isolation as a prezygotic barrier?
Which of the following scenarios best illustrates the concept of ecological isolation as a prezygotic barrier?
- Two species of birds are physically unable to mate due to differences in their reproductive structures.
- Two species of butterflies have different mating songs.
- Two species of snakes live in the same geographic area, but one lives in the trees while the other lives in the ground. (correct)
- Two species of frogs breed during different seasons.
A population of birds is geographically separated by a mountain range. Over time, the two subpopulations develop distinct songs and, even when the barrier is removed, no longer interbreed. Which of the following is the most likely order of events?
A population of birds is geographically separated by a mountain range. Over time, the two subpopulations develop distinct songs and, even when the barrier is removed, no longer interbreed. Which of the following is the most likely order of events?
- Genetic diversity → Isolation of the population → Reproductive barriers
- Isolation of the population → Reproductive barriers → Genetic diversity
- Reproductive barriers → Isolation of the population → Genetic diversity
- Isolation of the population → Genetic diversity → Reproductive barriers (correct)
Researchers studying a group of fossils find a series of organisms that appear to gradually change in morphology over millions of years. However, they have no information about reproductive compatibility. Which species concept would be MOST applicable in this situation?
Researchers studying a group of fossils find a series of organisms that appear to gradually change in morphology over millions of years. However, they have no information about reproductive compatibility. Which species concept would be MOST applicable in this situation?
Which of the following scenarios would be the LEAST likely to lead to speciation?
Which of the following scenarios would be the LEAST likely to lead to speciation?
Two plant species flower in the same geographic area, but one flowers in early spring and the other in late summer. This is an example of what kind of reproductive isolation?
Two plant species flower in the same geographic area, but one flowers in early spring and the other in late summer. This is an example of what kind of reproductive isolation?
A researcher is comparing two closely related species of fish. Species A lays its eggs on the sandy bottom of a fast-moving stream, while Species B lays its eggs in the calm waters of a pond. Even if the fish were to come into contact, they would not interbreed. This is an example of:
A researcher is comparing two closely related species of fish. Species A lays its eggs on the sandy bottom of a fast-moving stream, while Species B lays its eggs in the calm waters of a pond. Even if the fish were to come into contact, they would not interbreed. This is an example of:
Which situation poses the greatest challenge to defining species using the biological species concept?
Which situation poses the greatest challenge to defining species using the biological species concept?
A horse and a donkey can reproduce and create a mule. Mules are strong and can work, but they are sterile. This is an example of what?
A horse and a donkey can reproduce and create a mule. Mules are strong and can work, but they are sterile. This is an example of what?
Two species of plants can interbreed, producing fertile offspring. However, these offspring have low survival rates due to their inability to compete with the parent species for resources. This is an example of:
Two species of plants can interbreed, producing fertile offspring. However, these offspring have low survival rates due to their inability to compete with the parent species for resources. This is an example of:
A population of insects is divided by a newly formed river. Over time, the two populations diverge genetically due to different selection pressures. If the river dries up and the two populations can no longer interbreed, what has occurred?
A population of insects is divided by a newly formed river. Over time, the two populations diverge genetically due to different selection pressures. If the river dries up and the two populations can no longer interbreed, what has occurred?
In a plant population, a mutation occurs that doubles the number of chromosomes in some individuals. These individuals can only reproduce with each other, leading to a new species in the same geographic area as the original population. This is an example of:
In a plant population, a mutation occurs that doubles the number of chromosomes in some individuals. These individuals can only reproduce with each other, leading to a new species in the same geographic area as the original population. This is an example of:
Two populations of birds with slightly different mating songs come into secondary contact in a hybrid zone. Birds that produce hybrid songs are less successful at attracting mates than birds that sing either of the two parental songs. What outcome is MOST likely in this hybrid zone?
Two populations of birds with slightly different mating songs come into secondary contact in a hybrid zone. Birds that produce hybrid songs are less successful at attracting mates than birds that sing either of the two parental songs. What outcome is MOST likely in this hybrid zone?
Fossil records of certain species show long periods of stasis (no change) interrupted by sudden bursts of evolutionary change. Which evolutionary model does this observation support?
Fossil records of certain species show long periods of stasis (no change) interrupted by sudden bursts of evolutionary change. Which evolutionary model does this observation support?
In a population of flowering plants, differences in floral structure prevent pollen transfer between two groups. One group has long, tubular flowers that only hummingbirds can pollinate, while the other has open, flat flowers that are pollinated by bees. This is an example of:
In a population of flowering plants, differences in floral structure prevent pollen transfer between two groups. One group has long, tubular flowers that only hummingbirds can pollinate, while the other has open, flat flowers that are pollinated by bees. This is an example of:
Sea urchins release sperm and eggs into the water for fertilization. Different species of sea urchins have different proteins on the surfaces of their eggs and sperm that prevent proper fertilization. This is an example of:
Sea urchins release sperm and eggs into the water for fertilization. Different species of sea urchins have different proteins on the surfaces of their eggs and sperm that prevent proper fertilization. This is an example of:
Flashcards
Species
Species
A group of organisms that can interbreed and produce viable, fertile offspring.
Biological Species Concept
Biological Species Concept
The concept that defines species based on their ability to produce viable, fertile offspring.
Morphological Species
Morphological Species
Distinguishing species based on physical similarities and differences.
Ecological Species
Ecological Species
Signup and view all the flashcards
Phylogenetic Species
Phylogenetic Species
Signup and view all the flashcards
Speciation
Speciation
Signup and view all the flashcards
Reproductive Barriers
Reproductive Barriers
Signup and view all the flashcards
Prezygotic Isolation
Prezygotic Isolation
Signup and view all the flashcards
Mechanical Incompatibility
Mechanical Incompatibility
Signup and view all the flashcards
Gametic Incompatibility
Gametic Incompatibility
Signup and view all the flashcards
Hybrid Viability
Hybrid Viability
Signup and view all the flashcards
Hybrid Fertility
Hybrid Fertility
Signup and view all the flashcards
Allopatric Speciation
Allopatric Speciation
Signup and view all the flashcards
Sympatric Speciation
Sympatric Speciation
Signup and view all the flashcards
Polyploidy
Polyploidy
Signup and view all the flashcards
Punctuated Equilibrium
Punctuated Equilibrium
Signup and view all the flashcards
Study Notes
- Many species were originally distinguished by morphology but biological species are based on the ability to reproduce
Species Concepts
- Biological Species Concept: Organisms can produce viable, fertile offspring but not with other groups
- Morphological Species Concept: Organisms that look alike belong to the same species; DNA analysis increasingly influences taxonomic placement
- Ecological Species Concept
- Phylogenetic Species Concept: Examining small but meaningful differences between organisms
Biological Species Limitations
- Asexual reproduction and unobserved reproduction can cause limitations
Reproductive Barriers and Speciation
- Reproductive isolation is essential for speciation, preventing fertile hybrids, and most species have multiple barriers
Prezygotic Isolation
- Prezygotic barriers hinder zygote formation
- Geographical isolation: Prevents interbreeding
- Ecological (Habitat) Isolation: Isolation from habitat choice
- Temporal Isolation: Different breeding seasons
- Behavioral Isolation: Incompatible mating behaviors
- Mechanical incompatibility: Physical barriers prevent mating
- Gametic Incompatibility or isolation: Sperm and eggs are chemically mismatched
Postzygotic Isolation
- Postzygotic barriers hinder zygote development and propagation
- Hybrid Viability: Offspring are weak or lack survival skills
- Hybrid Fertility: Hybrids are sterile or have diminished fertility
- Hybrid Breakdown: Initial hybrids are viable and fertile, but later generations have reduced viability or fertility
Mechanisms of Speciation
- Isolation of a population and genetic diversity are the two main components of speciation
- Speciation is driven by evolution
- Allopatric speciation (geographic isolation) requires geographically isolated gene pools
- Sympatric speciation occurs within the same geographic area
Allopatric Speciation
- The type of necessary barrier depends on the species
Sympatric Speciation
- Results from radical mutations
- Polyploidy: An extra chromosome set(s) common among plants where offspring survive but often cannot reproduce sexually
Hybrid Zones
- Hybrid zones are regions where diverged populations make secondary contact and interbreed
- Reinforcement, fusion, and stability are possible outcomes for hybrids
Evolutionary Rates
- Gradualism: New species evolve from gradual accumulation of characteristics
- Punctuated Equilibrium: Speciation occurs during brief periods of rapid change followed by periods of stability
- The rarity of transitional fossils supports punctuated equilibrium
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Explore species concepts including biological, morphological, ecological, and phylogenetic. Understand reproductive barriers like prezygotic isolation, geographical isolation, habitat isolation, and temporal isolation. Discusses limitations of the biological species concept.
