UNIT 7 ck12’s 5.22-5.23 Flashcards
What is macroevolution?
Evolution over geologic time above the level of the species.
What is the process by which a new species evolves called?
Speciation.
What is a species?
A group of organisms that can breed and produce fertile offspring together in nature.
What must happen for a new species to arise?
Some members of the species must become reproductively isolated from the rest.
How does reproductive isolation typically occur?
Usually through geographical isolation.
What is allopatric speciation?
Speciation that occurs when some members of a species become geographically separated and evolve genetic differences.
What happens if the genetic differences prevent interbreeding with the original species?
They have evolved into a new species.
What is the term for a new species arising without geographic separation?
Sympatric speciation
This occurs when populations evolve reproductive isolation while living in the same geographic area.
What is coevolution?
Coevolution is the process where species in symbiotic relationships evolve together in response to changes in each other.
How does environmental change relate to coevolution?
Environmental change often involves other species, prompting coevolution as species adapt to each other’s changes.
What happens to one species during coevolution when the other species changes?
The other species must also change in order to adapt.
What is the relationship between coevolution and symbiotic relationships?
Coevolution occurs specifically in species that are in symbiotic relationships.
What types of relationships can exist in coevolution?
Relationships may be positive for one species or both, or may be an evolutionary arms race between predator and prey.
What is an evolutionary arms race?
An evolutionary arms race is a situation where predator and prey evolve in response to each other’s adaptations.
What does the endosymbiotic theory describe?
A special form of co-evolution involving mitochondria and chloroplasts within eukaryote cells.
The theory suggests that these organelles were once free-living prokaryotes that entered into a symbiotic relationship with ancestral eukaryotic cells.
What is a key characteristic of mitochondria and chloroplasts according to the endosymbiotic theory?
They have their own DNA sequence, different from that of the nucleus in the host cell.
This independent DNA supports the idea that they were once separate organisms.
How do mitochondria and chloroplasts evolve in relation to eukaryote cells?
They evolve in tandem, influencing each other’s evolution.
This co-evolution highlights the interdependence between the organelles and the host cell.
