What is Gradualism in the context of evolution?
Change occurs gradually over a long time period
Gradualism suggests that species evolve continuously through small, incremental changes.
What does Punctuated equilibrium describe in evolutionary theory?
Rapid evolutionary change followed by long periods of equilibrium
It indicates that species remain relatively unchanged for long periods, interrupted by brief episodes of rapid change.
What are the main conclusions of biological evolution?
- Life has a long history
- Life has changed over time
- Different species share common ancestors
These conclusions highlight the interconnectedness of all life forms.
What does the Tree of Life represent?
A branching pattern of evolutionary relationships
It illustrates how different species are related through common ancestry.
What are the types of evidence supporting biological evolution?
- Comparative Anatomy
- Embryology
- The Fossil Record
- Molecular Genetics
- Biogeography
These evidences provide insights into the evolutionary history and relationships among species.
Define Macroevolution.
Large scale evolution leading to new species from a common ancestor
It encompasses significant evolutionary changes over long periods.
What is Microevolution?
Small scale changes in genetic makeup of populations from generation to generation
It involves changes in allele frequencies within a population.
Who proposed the idea that acquired changes are inherited?
Jean Baptiste Lamarck
He suggested that organisms adapt to their environment and pass these adaptations to their offspring.
What is the driving force of evolution according to Charles Darwin?
Natural selection
It is often summarized as ‘survival of the fittest’.
What is a species?
Populations of organisms capable of interbreeding under natural conditions
This definition emphasizes reproductive isolation from other groups.
What is the gene pool?
The sum of all the alleles in a population
It represents the genetic diversity available for evolution.
What are prezygotic isolating mechanisms?
- Geographic
- Temporal
- Behavioral
- Ecological
- Mechanical
- Gametic isolation
These mechanisms prevent mating or fertilization between species.
What are postzygotic isolating mechanisms?
- Hybrid viability
- Hybrid infertility
- Hybrid breakdown
These mechanisms reduce the fitness of hybrid offspring after fertilization.
What is Allopatric speciation?
Speciation that occurs when populations are geographically isolated
This isolation reduces gene flow between populations.
What is the Hardy-Weinberg principle?
A mathematical model describing genetic equilibrium in populations
It specifies conditions under which allele and genotype frequencies remain constant.
List the conditions for Hardy-Weinberg Equilibrium.
- No new mutations
- No natural selection
- Large population size
- No migration
- Random mating
These conditions are rarely met in natural populations.
What are the primary sources of genetic variability?
- Mutations
- Gene flow
- Genetic drift
- Natural selection
- Sex
These factors contribute to changes in allele frequencies within populations.
What is clinal variation?
A pattern of smooth variation in traits along a geographical gradient
It often results from gene flow between adjacent populations adapting to different conditions.
