How is a “species” defined in a biological context?
A species is the “specific” category to which an organism belongs. It is often defined based on whether individuals from the group can produce fertile offspring together.
Define “genus”
ex: To what Genus do both Brown Bears (Ursus arctos) and Polar Bears (Ursus maritimus) belong?
The ‘generic’ category to which an organism belongs.
From the example: Ursus
How is evolution defined?
the gradual change in populations of living organisms
What is the primary difference between a gene and a genome?
gene: basic functional unit of heredity consisting of a sequence of DNA or RNA bases that provide instructions for a single cell function.
genome: the complete sequence of all DNA or RNA bases within an organism.
What is an inherited trait that enhances an organism’s survival and reproduction in a specific environment called?
an evolutionary adaptation
How does natural selection function as a mechanism for evolution?
Natural selection is the primary mechanism of evolution where advantageous genetic traits are more likely to be passed to subsequent generations over time. This process ensures that traits enhancing survival and reproduction become more common in a population.
Compare the reproductive processes of prokaryotes and eukaryotes in asexual reproduction.
Prokaryotes: reproduce asexually through a process called binary fission.
Eukaryotes: use a process called mitosis to replicate their cells, resulting in two identical daughter cells with the same genetic composition as the parent.
What is inheritance/heredity?
The passage of genetic information from one generation to the next
Define mutation
A random change in the RNA or DNA of an organism.
Why is asexual reproduction considered relatively slow at increasing genetic diversity?
This process is slow at increasing diversity because it is designed to produce identical photocopies of the parent cell. Genetic variation only increases when random mutations are introduced during the duplication of genetic material.
In the context of sexual reproduction, how are “female” and “male” defined?
In organisms with two types of gametes, those that produce the larger gametes are defined as female. Conversely, those that produce the smaller gametes are defined as male.
What is the study of the evolutionary history of a species or group of related species?
Phylogeny
What occurs during the process of recombination in sexual reproduction?
During sexual reproduction, genetic material from two parents is mixed via recombination. Because segments of DNA cross over from one chromosome to another, the resulting daughter cell possesses a unique version of genetic contributions from both parents.
What is the term for cells, such as gametes, that contain only one set of chromosomes?
what about two?
Haploid.
Two is Diploid.
Compared to asexual reproduction, what is the primary advantage of sexual reproduction for evolution?
Faster genetic reorganization and testing of new large-scale genetic combinations.
Explain the concept of the “molecular clock.”
The molecular clock concept posits that organisms accumulate mutations at a reasonably stable rate over generations. Consequently, the number of mutations can serve as a proxy for the amount of time that has elapsed since two species shared a common ancestor.
How can scientists calibrate the molecular clock to determine when species diverged?
The molecular clock is calibrated by comparing genetic data against the fossil record. This allows scientists to establish a chronological timeline for the divergence of different lineages.
Why are most mutations easily passed to the next generation?
Because they are neutral and do not affect the organism’s fitness
Describe the genetic similarity between humans and other organisms like rice and chimpanzees.
Humans share a surprising amount of genetic material with diverse life forms, including 22% similarity with rice. We share 90% of our genetic sequence with chimpanzees and 84% with dogs.
In a standard phylogenetic tree, what do the “root” and the “tips” represent?
The root of a phylogenetic tree represents the common ancestor of all species depicted in the diagram. The tips at the top of the tree represent species that are currently living.
How should a reader interpret the nodes (branching points) on an evolutionary tree?
Nodes are the branching points on a tree that indicate the splitting of an ancestral lineage into different descendent lineages. They represent the most recent common ancestor shared by the branches extending from that point.
What determines the genetic relationships on a tree rather than the left-to-right placement of branches?
Genetic differences are indicated by the length of the branches and the placement of nodes, not the horizontal order of the branches. Scientists can flip or rotate branches to emphasize different relationships without changing the underlying genetic information.
Why might a scientist flip or rotate the branches of an evolutionary tree?
To emphasize certain relationships without changing the genetic information.
What is the “Last Universal Common Ancestor” (LUCA)?
the “root” of the entire tree of life. It represents the common ancestral population from which all current life on Earth—Bacteria, Archaea, and Eukarya—descended.
