BIOL 1204 Midterm Vocab Flashcards
Define Biodiversity
- the variety of all life as reflected in
- genetic variability within species
- differences between species
- the number of individuals and species
- the variety of communities and ecosystems
Define Ecosystem Services
Ecosystem functions that directly or indirectly benefit humans
Define Evolution
Intergenerational change or descent with modification
Define Adaptation
A heritable trait that helps an organism to survive and/or reproduce and advantageous alleles become more common and disadvantageous ones become less common
Define Phenotypic Plasticity
When a single genotype can exhibit different phenotypes in different environments (rabbits in summer vs winter change coat colour)
Define Mutation
Any change in the DNA nucleotide sequence
Define Sexual Reproduction
Mixing of genes from different sources
Define Heritability
Percentage of phenotypic variance that is due to genetic factors
Define Vestigial Structure
Non-functional features fully developed and functioning in earlier species but serve little or no purpose for an organism today
Define Genotype
Combination of alleles in an individual organism
Define Phenotype
Observable traits of an individual organism
Define Gene
Functional unit of DNA
Define Alleles
Variants of the same gene
Define Locus (Loci)
Location of the gene on a chomosome
Define Species
A group of individuals that can potentially interbreed with one another and that is reproductively isolated from other groups
Define Subspecies
Is a group within a species that has become somewhat physically and genetically different from the rest of the group. But still similar enough to interbreed with the rest of the species.
Define Population
A group of individuals of the same species with a probability of mating with each other
Define Gene Pool
All the alleles in a population
Define Population Genetics
Is the study of genetic variation and how it changes in populations over time
Define Haploid (n)
A cell or an organism that only has one set of chromosomes
Define Diploid (2n)
A cell or an organism has two sets of chromosomes
Define Natural Selection
The survival and reproduction of individuals in a population due to differences in phenotype that are advantageous traits
Define Gene Flow
The movement of alleles between populations
Define Genetic Drift
Allele frequencies change due to random chance alone
Define Fixation
When only one allele exists at a gene locus for an entire population
Define Population Bottleneck
When a population undergoes a drastic population decline
Define Founder Effect
When a small number of individuals colonizes a new location where that species has never existed before
Define Heterozygosity
There are two different alleles for a specific gene, one inherited from each parent.
Indicates genetic diversity within a population.
Define Phenotypic Advantage
When an organism’s physical traits increase its chances of surviving and reproducing in a particular environment
Ex: Camaflouge
Define Sexual Selection
Type of natural selection where the advantage is related to mate choice
Define Stabilizing Selection
Type of natural selection that favors (middle) traits and reduces extremes, keeping traits in a population stable over time
Define Directional Selection
Type of natural selection where one extreme trait is favored over middle or other extreme phenotypes causing the population’s traits to shift in that direction over time
Define Diversifying Selection
Process by which a species becomes better suited to its environment through natural selection, where beneficial traits increase in frequency over generations
Define Speciation
Formation of new species from existing species
Define Allopatric Speciation
Populations are reproductively isolated because a geographic barrier prevents gene flow
Define Sympatric Speciation
Barriers preventing gene flow are reproductive, not geographic
Speciation occurs in the same geographic location
Define Vicariance
When a natural situation arises that physically separates a species
Define Dispersal
When a few members of a species move to another geographical area
Define Endemic
When species are unique to a location; not native to any other location
Define Adaptive Radiation
A single ancestor splits into many species over a short period of time
Define Aneuploidy
Is the nondisjunction during anaphase of meiosis and results in gametes with too few or too many chromosomes in a haploid set
Define Polyploids
Offspring from gametes with too many chromosomes, and cannot mate back into the population
Define Taxonomy
The science and system of classifying organisms
Define Taxon (Taxa)
A single level in the taxonomic classification system
Define Binomial Nomenclature
The system of naming species using two Latin-based names: the first is the genus name (capitalized), and the second is the species name (lowercase).
Ex: Homo sapiens
Define Phylogenetic Systematics
The science and system of classifying organisms to reflect their phylogeny
Define Phylogeny
Evolutionary history
Define Root
Common ancestor to all organisms
Define Branch Point
Where two lineages diverged
Define Basal Taxon
A lineage that evolved early and remains unbranched
Define Sister Taxa
When two lineages stem from the same branch point
Define Polytomy
A branch with more than two lineages
Define Homologous Characters
Characters that are inherited from a common ancestor, but serve a different function in the descendents
Define Analogous Characters
Serve a similar function but originated as different characters in different ancestors
Define Evolutionary Divergence (Divergent Evolution)
This happens when two related species become more different from each other over time, usually due to different environments or ways of life. They start from a common ancestor but evolve into distinct forms.
Define Evolutionary Convergence (Convergent Evolution)
This occurs when unrelated species develop similar traits or characteristics because they live in similar environments or face similar challenges, even though they don’t share a recent common ancestor.
Define Ancestral Characters
When there are inherited characters from ancestors
Define Derived Characters
Newly evolved characters
Define Monophyly (Monophyletic)
Derived from a single, common ancestor
Define Paraphyly (Paraphyletic)
One or more descendants are missing
Define Polyphyly (Polyphyletic)
Grouping includes organisms with different ancestry
Define Clade
A monophyletic group
Define Neutral DNA Sequences
Some DNA sequences mutate at a constant rate
Define Molecular Clock
Neutral sequences not subjected to natural selection
Can then be used to estimate how long ago organisms branched from a common ancestor
Define Synapomorphy
A trait shared by two or more clades and a most recent common ancestor
Define Chimeric
Having parts of different origins
Organism has cells with different genetic material from more than one source. This can happen naturally or through experiments
Define Autotrophic
Carbon source is inorganic
Ex: Atmospheric or dissolved carbon dioxide
Define Heterotrophic
Carbon source is organic (must consume another organism)
Define Mixotrophic
Can use either Heterotrophy OR Autotrophy
Define Horizontal Gene Transfer (HGT)
The introduction of genetic material from one species to another by mechanisms other than the vertical transmission from parent(s) to offspring.
Define Crossing Over
Is the pieces of chromsomes that are swapped between homologous chromosomes during Prophase I. Results in gametes with a unique combination of alleles.
Define Independent Assortment
The number of gametes with a unique combination of alleles
Define Porin Proteins
On the plasma membrane of bacterial cells and allow a cell to uptake nutrients for growth
Define Mutated Porin Allele
These are bacteria that slow the uptake into the cell
Define The Hardy-Weinberg Principle of Equilibrium
States that allele and genotype frequencies will remain the same from one generation to the next UNLESS, something causes the population to change (e.g evolve)
Define Genotype Frequencies
The proportion of genotypes that are AA, Aa, or aa
Define Phenotype Frequencies
The proportion of individuals expressing a particular phenotype in a population
Define Allele Frequencies
Proportion of genes in the gene pool that are either A or a
Define Sterile Inflammation
Damaged cells release mitochindria and the immune system mistakes it for invading bacteria
Define Prezygotic Barriers
Reproductive barriers before fertilization
Define Postzygotic Barriers
Reproductive barriers after fertilization
