Evolution Flashcards
What is the role of DNA in evolution?
Chromosomes are made of DNA. It determines what characteristics an organism will have
What’s a mutation
It’s a change that occurs in DNA sequence due to mistakes when DNA is replicated. It can potential create new alleles for a trait
What is mitosis?
Responsible for growth and repair.
Asexual reproduction that only need one parent.
Produces genetically identical offspring.
No specialized structures are required.
What is Meiosis?
Sexual reproduction, usally requires two parents but not always.
Usually produce a smaller number
of genetically diverse offspring.
Requires formation of specialized structures, only function in reproduction.
How does mitosis occur?
After replication occurs, diploid or haploid cells are copied to make new cells which are identical to the original, or parent cells.
Homologous pairs do not come together and crossing over does not occur.
How does Meiosis 1 occur?
Homologous pairs come together and line up at equator.
The homologous pairs are pulled apart and move to opposite ends of the cell. the cell membrane pinches in, creating two cells.
How does meiosis 2 occur?
Chromosomes, composed of sister chromatids, line up at the equator of both new cells.
Sister chromatids are pulled apart at the centromere, to form two chromosomes, which are pulled to opposite sides of the cell.
Each of the two cells pinches in half forming 4 daughter cells called gametes. Each gamete is genetically unique.
What is natural selection?
A random genetic mutation occurs in an organisms genetic code.
the beneficial mutations are preserved because they aid for survival.
These mutations are passed on to the next generation over and eventually result in a different organism.
how does the process is Meiosis occur?
Process where the number of chromosomes is reduced by half, from diploid (2N) to haploid (N).
There are 2 stages, meiosis 1 and meiosis 2, occurs after replication is complete.
What is gene flow?
Occurs when genetic information from one population moves to another population.
Can occur through the migration of organisms or the flow of gametes.
Happens more in small populations.
What is Genetic drift?
Occurs when chance or random events cause changes in allele frequencies within a population.
Population’s size becomes very small.
Many alleles may be lost or reduced causing the genetic variation of a population to decrease.
What are homologous structures?
Similar physical characteristics in any organism that have a common ancestor, however serves a completely different purpose.
The opposite of evolutionary relationships.
What are evolutionary relationships?
A connection between different species that emerge from their common ancestry.
These relationships are often shown using an evolutionary tree that show how species diverged from a common ancestor over time.
What is Embryonic development?
Comparative embryology studies the similarities and differences in the embryos of different species.
Species that share a common ancestor often exhibit similar embryonic stages even if adult forms are very different.
