Biology Chapter 1
Flashcards: Species Concepts & Evolutionary Terms
Flashcard 1
Q: What is the biological species concept?
A: Species are groups of actual, or potentially, interbreeding natural populations that are reproductively isolated from other such populations.
Flashcard 2
Q: Who proposed the biological species concept?
A: Ernst Mayr, in the early 1940s, building on ideas from Charles Darwin.
Flashcard 3
Q: What is a gene pool?
A: The range of genes and all their alleles present in a population.
Flashcard 4
Q: How does the biological species concept relate to gene pools?
A: Each species represents an isolated gene pool where individuals can interbreed and produce viable offspring under natural conditions.
Flashcard 5
Q: What are the main limitations of the biological species concept?
A:
Fossils: Cannot determine interbreeding or whether differences denote new species
Proof of mating: Difficult to observe in some environments (e.g., deep ocean)
Hybrids: Interbreeding between two species produces organisms that may survive poorly or complicate classification
Flashcard 6
Q: What is a hybrid?
A: An organism resulting from the interbreeding of two different species.
Flashcard 7
Q: Why are hybrids challenging to classify?
A: They often occupy restricted hybrid zones, may not survive well, and may blur species boundaries, making it difficult to determine parent species.
Flashcard 8
Q: Give an example of a hybrid observed in the wild.
A: Polar–grizzly bear hybrid, also called a “grolar bear,” observed in Arctic regions.
Flashcard 9
Q: What is the morphological species concept?
A: A definition of species based on physical characteristics.
Flashcard 10
Q: What is the phylogenetic species concept?
A: A definition of species based on the smallest group of individuals with a common ancestor, often determined using genetic analysis.
Flashcard 11
Q: Why might the biological species concept fail with fossils?
A: Fossils don’t show mating behavior, fertility of offspring, or reproductive isolation, so it’s impossible to apply this concept to extinct organisms.
Flashcard 12
Q: How does hybridization challenge species definitions?
A: Hybrids can survive in overlapping zones, indicating genetic compatibility, but their existence complicates determining whether parent populations are truly separate species.
Flashcard 13
Q: Which species concept is most widely used in modern biology?
A: The biological species concept.