Bio Diversity Kent State Kershner Exam 2 2023

Morphospecies approach, and what issues arise from it?

Uses physical appearance/Morphology to define a species. It doesn't deal well with Sexual Dimorphism

Sexual Dimorphism

Females/Males look different from each other.

Cryptic Species:

two or more species who are identical, but rarely capable of successful reproduction.

Polymorphic Species

Individuals of the same species who look different- but can breed successfully.

Biological Species Concept

Species as groups of potentially interbreeding natural populations that are reproductively isolated from other such groups. [Created by Ernst Mayr]

Issues with Biological Species Concept

Cant be applied to asexual organisms. [Prokaryotes, bacteria, archaea, some hermaphrodites/self-fertilizers]

Can't be used to define species for extinct fossil organisms

Difficult to apply to populations that are separated
geographically -> no way to assess their potential to reproduce [Like jaguars/Leopards; separated by the Atlantic ocean]

Phylogenetic Species Concept

o Based upon the evolutionary history of individual populations..

o Considers COMMON ANCESTRY

o Descendant populations/species are often separated from each other based upon trait/allele differences. -> Synapomorphies

o Reproduction isolation can also be used

o Can be applied to any organism. Including fossils, asexual, sexual

Reproductive Isolation

Factors that prevent successful reproduction and gene flow. Divergence results form differences in how mechanics of evolution affect each population. Over time, can lead to speciation

Speciation

Creation of new Species

Genetic Isolation

Occurs through some form of reproductive isolation
No Gene Flow, barrier in place

Genetic Divergence

Can occur through effects of different mechanisms of evolution with each isolated population.

o Requires reproductive isolation

Prezygotic isolation

Mating typically can't occur

Mechanical Isolation:

Physically impossible for breeding to occur, normally due to female/male reproductive parts don't match up.

Body Size mismatch

Lock and Key mismatch

Habitat Ecologic Isolation

· Organisms live in same location, but some ecological factors differ between them; preventing mating.

(Mating can occur, but doesn't)

Behavioral Isolation

· Organisms live in same location, but some aspects of behaviors differ between them

· Difference in song/calls, dances or movement, or any courtship ritual.

· Lacewings example [Noise differences]. Anoles (dewlaps)

(Mating can occur, but doesn't)

Temporal Isolation

· Breeding periods of similar, closely related species occur at different times.

· No potential at interbreeding

(Mating can occur, but doesn't)

Isolation by prevention of gamete fusion

· Something prevents sperm from fertilizing egg

· Sperm egg incompatibility: Sperm cannot penetrate the egg due to incompatibility of head of sperm and egg surface

(Mating occurs, but no fertilization results -> No zygote is formed)

Toxic uterine environment

Uterus kills sperm from wrong species

(Mating occurs, but no fertilization results -> No zygote is formed)

Post Zygotic Isolation

Mating occurs, fertilization occurs -> Zygote forms but other issues arise

Hybrid Unviability

Accumulation of genetic issues/differences resulting from mismatched sperm and egg

Death of zygote/offspring

(Mating occurs, fertilization occurs -> Zygote forms but other issues arise)

Hybrid infertility/sterility

Offspring produced by breeding of closely related species can survive to adulthood

However, they are sterile/infertile; no successful breeding of their own

Partial Isolation

· Individual that breeds with members of other population; frequently get low offspring/fitness. (Not sustainable)

The issue: Reproduction is energetically expensive
Mating with individuals from other population is wasted energy/effort

In contrast, individuals that breed within their population have much higher offspring survival and fitness.

Allopatric Speciation

Occurs when populations are separated geographically -> Breeding/gene flow are impossible

Through dispersal, population splits with one population moving to new location

Remain separated -> reproduction isolation -> Genetic divergence -> speciation

Ex: Large ground finch (Galapagos)
· Founder Effect: Leading to potential for allopatric speciation

Vicariance

Physical splitting of the habitat -> splits single population into 2 populations

Rivers changing flow path, volcanic action, continental drift, agriculture, ranching, roads

Sympatric speciation: "together homelands"

Populations live in the same area, but have no gene flow

Can also occur through adaptive radiation or major extinction events

Adaptive Radiation

Single species that rapidly evolves into multiple descendant species. May allow orgs to use new habitats/food, which can lead to reproduction isolation and no gene flow. [Also speciation]

How can Adaptive Radiation occur?

· 1: Intense competition for resources: Food/habitats/mates

· 2: Species must have LOTS of existing variations in traits [important for resource competition]

3: Through mutation/chromosomal events that prevents breeding between individuals within population mutation

4: When key new traits (morphological/physiological/behavioral) - evolve through mutation

When there is no-low competition, there would be low selective pressure to change your habitat/food, which means adaptive radiation is uncommon and speciation has a low rate of occurring
When competition is high, high selective pressure to change food/habitat. Adaptive radiation is common [ASSUMING HIGH TRAIT VARIATION] which causes high rates of [sympatric] speciation

Chromosomal event

Differences in chromosome number between parents and offspring (Polyploidy)

Can lead to fertile offspring -> New species due to increase in chromosome number.

Occurs during self fertilize in hermaphroditic spies

Errors during gamete production leads to tetraploid (4) offspring from diploid (2) parents

Can also occur through external events

Something alters/affects breeding habits or habitats of a given species, and alters gene flow

Autopolyploid:

Individuals from two very similar species interbreed; usually unsuccessful

Extinction

Speciation can occur [Sympatric speciation]
Can be rapid, large reductions in the number of species [days to years timeframe]
The death of dinosaurs opened up new habitats and opportunities for the species that survived
Can also have smaller, more gradual extinction events
Natural: ice ages
Human-driven; deforestation
Opens up chances for the survivors, which requires trait variation

Issues with naming in phylogenetics:

o Everyone names differently, using different approaches
o Physical characteristics [Noun, adjective]
o Resemblance to known organisms
o Combo of organisms [new words]
o Habitats
o Cultural references
o Personal experience
o Explorers/naturalist name organisms in their native language
o All of this leads to many different names for the same species

· Carolus Linnaeus

o Wrote system naturae
o Universal naming language [Latin]
o Review of new species -> avoid redundancy
o Binomial nomenclature; 2 name approach. ["Genus and a Species"]
o Hierarchical nomenclature
System for organizing species in terms of relatedness
Kingdom, Phylum, Class, Order, Family, Genus, Species.

· Carl Weese

o Added Domain above Kingdom
Bacteria, Archaea, Eukarya

Phylogenetic

Uses tools known as phylogenetic trees. [Cladograms]

Phylogenetic trees

Used to illustrate evolutionary relationships

· Prokaryotes: Include bacteria and Archaea

o Lack membrane bound nucleus
o EVERYWHERE
o Date back at least 35 billion years
Earliest form: Cyanobacteria
·Structures + fossil biochemical evidence [Lipids/pigments match with modern cyanobacteria]
Massive biodiversity
Use DNA, Physiology, molecular characteristics to describe diversity

· Archaea

o Some Symbiotes [positive relationship with other organisms]
o No pathogens/parasites (Negative relationship with other organisms]
o Mostly extremophiles; associated with extreme abiotic conditions/environments
o Classified based upon where find them living

Acidophiles

Associated with extremely low pH [Highly acidic, pH smaller than 2]
o Natural acidic habitats- Pine forest, bogs
o Food- Sour cream, yogurt, buttermilk
o Acid mine drainage
o Picrophilus spp: Optimal growth at pH 0.0
o Can block uptake of hydrogen ions with specialized cell walls/membranes

Thermophiles

Associated with extremely high temperatures
o Hot springs, geysers, hydrothermal events in ocean
o Optimal growth: 140-175F
oHeat stable enzymes allow for normal metabolism, growth, reproduction at the highest temperatures.
o Many break down hydrogen sulfide for energy and CO2 or other substrates not used by other organisms
o Ex; pyrococcus furiosus -> Hydrothermal vents
· Optimal Growth: Boiling water [212F]

Halophiles

Associated with extremely high salinity [High salt levels]
o Optimal Growth: 35-40% salinity
o Natural saline lakes [Great salt lake, dead sea]
o Food- Soy sauce, sauerkraut, kimchi
o Block salt uptake from the environment/Water loss to the environment
o Genes associated with cells walls/membranes make this possible

Methanogens

Known for their ability to produce methane [Atmospheric greenhouse gas]
o Natural and anthropogenic production
o Natural is about 36%
o Natural methanogen sources: Common in wetlands, deep oceans, some geological sources, termite guts
o Anthropogenic production: 64%
o Sources: Livestock digestive tracts loaded with archaea, Landfills/dumps, fossil fuels combustion [#1 source not associated with archaea]