Evolution - DP1 - Unit 1 Flashcards
Homologous structures
Similar physical features in organisms that share a common ancestor, but the features serve completely different functions.
Analogous structures
Biological structures having similar or corresponding functions but not from the same evolutionary origin
Divergent evolution
What occurs when two groups of the same species evolve different traits within those groups in order to accommodate for differing environmental and social pressures.
Convergent evolution
The process by which two species develop similar features despite not sharing a recent common ancestor.
Adaptive radiation
The process by which many species originate from one species in an area and radiate to different species.
Example: Hawaiian honeycreepers
Ecological niches
The position of a species within an ecosystem or community and its interrelationships with both bitoic and abiotic factors.
Hybridisation
The act or process of mating organisms of different varieties or species to create a hybrid.
Speciation
Process by which new species arise; involves the splitting of one ancesteral species into two or more descendent species which are genetically different from each and can no longer interbreed.
Reproductive isolation
the inability of a species to breed successfully with related soecies due to geographical, behavioral, physiological, or genetic barriers or differences.
Differential selection
The process of natural selection in which certain traits or variation within a population provide a selective advantage, leading to their increased frequency in generations, while other traits decrease in frequency or may be eliminated.
Allopatric speciation
evolution of one or more new species from an ancesteral species due to geographical barrier.
Sympatric speciation
evolution of one or more new species from an ancesteral species while living in the same geographical area.
Intraspecific breeding
sexual reproduction within the same species
geographical isolation
seperation of species by natural or human-made physical barriers.
temporal isolation
a result of differences in the timing of the reproductive cycle like mating or gamete production.
behavioural isolation
the presence or abscense of a specific behaviour that prevents reproduction.
Polyploidy
When a diploid cell or organism acquires one or more additional set of chromosomes. It is a consequence of the duplication of chromosomes in a cell without subsequent cell division, resulting in whole-genome duplication.
Allopolyploidy
A special case of polyploidy It is when a hybrid and has multpile chromosome sets that are derived from the different parental species. It can result in adbrupt speciation due to the hybrid not being able to mate with neither parent species.
Organism
Any biological system that functions as an individual life form.
Population
A group of organisms of the same species living in the same area at the same time.
Community
Two or more populations of different species living in the same area.
Discrete variation
Qualitative categories - bar graph
Continous variation
Quantiative categories - histogram
Species
Group of organisms that can successfully interbreed and produce fertile offspring.
Genome
A complete set of genetic material in an organism.
Gene
A specific segment of DNA that contains the intstructions for making a particular protein or functional RNA molecule.
Allele
One or more alternative forms of a gene that occupy the same position on a chromosome.
DNA barcodes
Short sections of DNA from one gene, or at most several genes, which are distinctive enough to identify a species.
Environmental DNA
Organismal DNA that can be found in the abiotic factors of the environment.
Applications of DNA barcoding using environmental DNA: invasive species detection, ecosystem health monitoring, biodiversity assesment, etc.
Evolution
A gradual, long-term process that involves changes in the genetic composition of populations of living organisms over successive generations. (”changes in the heritable characteristics”)
Vestigial structures
Features of an organism that are considered to have lost much or all of their original function through evolution.
Selective breeding
A process in which humans intentionally choose an mate individual organisms with specific desirable traits or characteristics to produce offspring with those traits.
Natural selection
The process by which organisms with advantageous traits or characteristics have a higher likelihood of surviving and reproducing in a given environment, passing those beneficial traits to their offsprings. (VIDA)
Biological variation
Diversity of traits and characteristics that exist within a population.
Selective pressures
Factors that lead to differential survival or reproduction, which in turn cause a change in the geentic composition of a population.
Density-dependent factors
Factors that affect the size of a population and depend on the density of the population.
Example: Availablity of food, predators, etc.
Density-independent factors
Factors that affect the size of a population, irrespective of the population density.
Example: Natural disasters, pollution, oxygen levels, etc.
Adaptation
Evolutionary process by which an organism or population acquires and develops traits, behavious, or physiological features that interests its fitness and enable it to better survive and reproduce in its specific ecological context.
Fitness
The ability of an organism to successfully reproduce and pass on its genetic material to its offspring.
Sexual selection
A special case of natural selection where the focus is on fincing a mate instead of survival.
Intrasexual survival
Competition between individuals of one sex to mate with opposite sex.
Intersexual selection
Indivdiauls of one sex choosing an inidividual of the opposite sex as a mate.
Gene pool
Sum total of all the alleles of all the genes in a population.
Allele frequency
The relative frequency of a particular allele in a population.
Stabilizing selection
Selection pressures act to remove extreme varieties.
Example: Average human baby birth weight is better than low or high.
Disruptive selection
Selection pressures act to remove intermediate variations, favoring both extremes.
Example: Mive living in an area with sandy beaches and dark-coloured rocks.
Directional selection
Selection pressures favour one extreme form of a trait over all other.
Example: Giraffes with long necks.
