Concepts of Speciation Flashcards
Latin word which means “having similar appearance”
Species
Biological Species Concept (2 items)
-Having similar genetic and morphologic traits.
-organisms that are capable of reproducing viable offsprings.
Is a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms.
Happens when a change in the environment creates new challenges. Organisms have to adapt to stressors.
Adaptive Radiation
Responses made by an organism that help it to survive/reproduce.
Behavioural Adaptation
A body process that helps an organism to survive/reproduce.
Physiological adaptation
A feature of an organism’s body that helps it to survive/reproduce.
Structural Adaptation
Individuals with favourable genetic traits are naturally selected to reproduce.
Natural Selection
Process by which the most adaptive traits for an environment become more common generation after generation.
Natural Selection
Frequencies of traits in a population change purely by chance.
Genetic drift
Happens when a random subset of a population dies. The remaining individuals are left to pass their traits to later generations. Thus, genetically, the population has changed.
Genetic drift
-Selection that acts collectively on all members of a given group. For instance, cooperation within a population to increase hunting success rate, survivability and fertilization are among such acts.
Group Selection
Process by which certain organisms or characters are reproduced and perpetuated in the species in preference to others.
Individual Selection
Selective pressures select against the two extremes of a trait, the population experiences ___
Stabilizing selection
One extreme of the trait distribution experiences selection against it. The result is that the population’s trait distribution shifts toward the other extreme.
Directional selection
Selection pressures act against individuals in the middle of the trait distribution.
Diversifying Selection
Happens when the size of a population is severly reduced. The remaining individual regardless of genetic traits are left to reproduce the succeeding generation.
Bottleneck Effect
Occurs when a small group of individuals breaks off from a larger population to establish a colony. The new colony is isolated from the original population, and the founding individuals may not represent the full genetic diversity of the original population.
Founder’s Effect
Is the creation of a new species.
Involves the splitting of a single evolution lineage into two or more genetically independent lineages.
All species on earth thought to share single common ancestor.
Speciation
The place or type of site where an organism or population naturally occurs.
Habitat
Restricted to a particular area: used to describe a species or organism that is confined to a particular geographical region, for example, an island or river basin.
Endemic species
are those which have an extremely high impact on a particular ecosystem relative to its population.
Keystone species
Species are groups of actually or potentially interbreeding natural populations that are reproductively isolated from such groups.
Biological species concept
Focuses on mechanisms that maintain species as discrete phenotypic entities. Each species is defined by its complex of genes and set of adaptations. Applicable to organisms that reproduce without sex.
Cohesion species concept
A species is a single lineage of ancestral and descendant populations that are evolving independently of other such groups.
Evolutionary species concept
Defined species by measurable anatomical differences (morphological criteria). It is practical to apply in the field, even to fossils.
Morphological species concept
A species is the smallest monophyletic group of common ancestry
Phylogenetic species concept
Emphasizes mating adaption’s that become fixed in a population as individuals “recognize” certain characteristics of suitable mates.
Recognition species concept
As a lineage of populations between two speciation events (phylogenetic branch points), based on the branch points not on how much change has occured between them.
Cladistic Species Concept
Populations form the discrete phenetic clusters that we recognize as species because the ecological and evolutionary processes controlling how resources are divided up tend to produce those clusters.
Ecological Species Concept
populations are separated by geographical isolation.
As great distance or a physical barrier - prevents two or more groups from mating.
Allopatric speciation
isolation occurs within a single population without geographic isolation.
Genetic divergence can happen within a population of individuals that are continually interacting.
Sympatric
5 Prezygotic Barriers
Habitat Isolation
Behavioral Isolation
Temporal Isolation
Mechanical Isolation
Gametic Isolation
Opulations live in a different habitat and do not meet
Habitat Isolation
Little to no sexual attraction between males or females
Behavioral Isolation
Mating or flowering occurs in different season or times of day
Temporal Isolation
Structural differences in genatalia or flowers that prevent copulation of pollen transfer
Mechanical Isolation
Male and female gametes fail to attract each other or are inviable
Gametic Isolation
3 Postzygotic Barrier
Reduced Hybrid Viability
Reduced Hybrid Fertility
Hybrid Breakdown
Zygotes fail to develop or fail to reach sexual maturity
Reduced Hybrid Viability
Hybrids fail to produce functional gametes
Reduced Hybrid Fertility
Offspring of hybrids have reduced viability and fertility
Hybrid Breakdown
Is the ultimate fate of a species. It is a natural or unnatural irreversible process of eliminating a species.
Extinction
The past great extinctions shared some important commonalities (4):
1 They caused a catastrophic loss of global biodiversity
2 They unfolded rapidly
3 Taxonomically, their impact was not random
4 The survivors were often not previously dominant evolutionary groups
7 Drivers of Extinction
1 Natural and Extra-terrestrial causes
2 Deforestation
3 Overexploitation
4 Disease
5 Pollution
6 Invasive Species
7 Climate Change
