4: Mechanisms of Population Change Flashcards
(22 cards)
What is sexual reproduction?
A process that combines the genetic information from two parents, resulting in variations in offspring characteristics.
What is the main source of variations in offspring?
Mutations.
When do mutations occur?
When DNA is copied during cell division.
Which mutations can be passed on to offspring?
Mutations that occur in reproductive cells.
What is natural selection?
The process where certain inherited traits become more common in a population because they provide a survival advantage.
What role does the environment play in population changes?
It is the driving force of changes as time passes.
What happens if an environmental change is severe enough?
Extinction is inevitable if no individuals have characteristics that enable survival.
Who developed the theory of evolution by natural selection?
Darwin and Wallace.
What is the title of Darwin’s publication on evolution?
On the Origin of Species.
In what year was On the Origin of Species published?
1859.
What fields have provided supporting evidence for the theory of evolution?
- Paleontology
- Biogeography
- Anatomy
- Embryology
- Genetics
- Molecular biology
What defines a biological species?
Organisms that can interbreed and produce healthy offspring that can also reproduce.
What leads to the formation of new species?
Reproductive isolation due to geographical or biological barriers.
What can happen to isolated populations over time?
Natural selection will occur differently, leading to variations that could prevent mating.
What is speciation?
The process by which new species form.
Does speciation always result in increased biodiversity?
No, it may or may not result in increased biodiversity.
What are the two main sources of variation among individuals in a population?
• sexual reproduction
• mutations in genes
This variation is crucial for natural selection.
What do selective pressures act on in a population?
Individuals with inherited variations that provide a survival advantage
This process is fundamental to the theory of evolution.
What do various lines of evidence from biology and geology indicate?
• populations change over time
• different species are related to one another
These findings support the theory of evolution and common descent.
What is speciation?
The process by which ancestral species transform or diverge into new species
Speciation can occur due to various factors, including geographical isolation.
Name the two hypotheses about the pace of speciation.
• gradualism
• punctuated equilibrium
Gradualism suggests slow, incremental changes, while punctuated equilibrium proposes rapid changes followed by periods of stability.
What are the two types of barriers that lead to reproductive isolation of species?
• geographical barriers
• biological barriers
These barriers prevent interbreeding between different species.
