AI generated deck from ch 18 notes Flashcards
Who famously stated that ‘nothing makes sense in biology except in the light of evolution’?
Theodosius Dobzhansky
What is the theory of evolution considered in biology?
The unifying theory of biology
Define adaptation.
Heritable trait or behavior in an organism that aids in its survival and reproduction in its present environment.
What is the difference between convergent and divergent evolution?
Divergent evolution is when groups evolve in diverse directions from a common point, while convergent evolution is when groups independently evolve to similar forms.
What are homologous structures?
Parallel structures in diverse organisms that have a common ancestor.
What are vestigial structures?
Physical structures present in an organism that have no apparent function and appear to be from a functional structure in a distant ancestor.
Name a key misconception about the theory of evolution.
Evolution is just a theory.
Who reintroduced ideas about the evolution of animals in the 18th century?
Georges-Louis Leclerc Comte de Buffon
What did Charles Lyell contribute to the understanding of Earth’s geology?
He popularized the notion of the greater age of Earth, allowing more time for gradual change in species.
What mechanism for evolutionary change did Jean-Baptiste Lamarck propose?
Inheritance of acquired characteristics.
What are the three principles of natural selection proposed by Darwin?
- Most characteristics of organisms are inherited.
- More offspring are produced than are able to survive.
- Offspring vary among each other in regards to their characteristics.
What is genetic variation?
Genetic differences among individuals in a population.
What is the significance of fossils in the study of evolution?
Fossils show gradual evolutionary changes over time via carbon dating.
Define biogeography.
The branch of biology that deals with the geographical distribution of plants and animals.
What is molecular biology’s contribution to evidence of evolution?
DNA’s universality reflects evidence of a common ancestor for all of life.
True or False: Individuals evolve.
False
What does speciation refer to?
Formation of a new species.
What is allopatric speciation?
Speciation that occurs via geographic separation.
What is sympatric speciation?
Speciation that occurs in the same geographic space.
What is adaptive radiation?
Speciation when one species radiates to form several other species.
What are prezygotic barriers?
Reproductive isolation mechanisms that occur before zygote formation.
Fill in the blank: The _______ is a situation that occurs when a species is reproductively independent from other species.
reproductive isolation
What type of reproductive barrier occurs when fertilization takes place but hybrid individuals cannot survive?
Hybrid inviability
What is hybrid sterility?
A postzygotic situation where hybrid birth occurs but the offspring are sterile.
What is the gradual speciation model?
A model showing how species diverge gradually over time in small steps.
What is punctuated equilibrium?
A model for rapid speciation that can occur when an event causes a small portion of a population to diverge quickly.
What happens when hybrids are less fit than the parents?
Speciation reinforcement occurs, leading to continued divergence until they can no longer mate and produce viable offspring.
This process emphasizes the importance of reproductive barriers in maintaining species integrity.
What occurs if reproductive barriers weaken?
Fusion occurs and the two species become one.
This indicates that the stability of species can be influenced by the fitness of hybrids.
What is the outcome if hybrids are fit and reproductive?
Stability may occur and hybridization continues.
This suggests that hybrids can play a significant role in the evolutionary process.
Define the gradual speciation model.
A model that shows how species diverge gradually over time in small steps.
This model contrasts with more abrupt speciation events.
What is punctuated equilibrium?
A model for rapid speciation that can occur when an event causes a small portion of a population to be cut off from the rest of the population.
This model highlights the impact of environmental changes on speciation rates.
True or False: Hybrids typically tend to be more fit than their parent species.
False
Generally, hybrids are considered less fit compared to their parent species.
