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TOWSON / Biology / BIOL 202 / Who proposed typological species concept?

Who proposed typological species concept?

Who proposed typological species concept?


School: Towson University
Department: Biology
Course: Introduction to Ecology and Evolution
Professor: John lapolla
Term: Spring 2017
Cost: 50
Name: Intro. Ecology and Evolution- Study Guide 2
Description: These are very helpful notes for our upcoming exam! Why Stress the notes are here!
Uploaded: 03/13/2017
5 Pages 204 Views 4 Unlocks

Ecology and Evolution-Study Guide 2

Who proposed typological species concept?

Chapter 22- Origin of Species AND Speciation


∙     the distinctiveness of species that occur together at a single locality ∙     the connection that exists among different populations belonging to the same species

∙     Major concepts

 Typological Species Concept: a group of organisms where  individuals are members of the species if they conform to certain fixed  properties → meaning individuals share the same characteristics in the  same group

 Biological Species Concept: is a group of individuals in one or more  population which potentially interbreed with one and another and  produce viable, fertile offspring.  

Which best describes the biological species concept?

o Really focus on process- based concept If you want to learn more check out What is ram memory in computer?
If you want to learn more check out What causes sudden lockjaw?

 The group is reproductively isolated, meaning genes from other  one species generally will not enter the gene pool of another

reproductive component

 Variation, meaning organisms will have genetic differences by  environmental factors- ecological component

 Interbreeding: a species is a gene pool- genetic component Don't forget about the age old question of What environmental factors suggest that the concept would be successful?



o Experiment: A test cross

o Field Observations-sympatry (integrating  

population of A and B)

o Inference: look different in some way

What is it called when many species evolve from one ancestral species?

∙    Difficulties  

o Interbreeding  

o Hybrids (offspring between two different taxa) are  

eliminated for the gene pool

o Asexual species  

 Phylogenetic Species Concepts(pattern-based): species are  lineages of ancestor- descendant populations

 Species are historical entities  

∙     Cladogenesis- a parent species splits into two distinct  

species, forming a clade (organisms end up in some new  Don't forget about the age old question of What is the difference between empiricism and rationalism?

distant areas or when environmental changes cause  


∙     Undergo evolution

∙     Species appear and disappear

 Difficulties  

o Understanding phylogeny


∙ Carolus Linnaeus first one to defined species and the Latin name system ∙ Linnaeus’ innovation was grouping of genus into higher taxa to show shared  similarities  

Modern Biological Classification scheme

 Reproductive Isolating Mechanisms- (prevent genetic exchange between  species) 

∙ Prezygotic Isolating mechanism: mechanisms that prevent the formation of  zygotes

o Ecological isolation  

 Species occur in the same area, but occupy different habitats  and do not encounter with each other  Don't forget about the age old question of What is measured in hertz?

 Example: They do not hybridize like tigers and lions

o Behavioral isolation

 Species differ in the mating rituals even if they inhabit the same  environment  

 Some species rely on pheromones (chemicals signals) or mate  calling

 Species are distinct

 Example: lacewings rely on auditory signals to attract males

o Temporal Isolation

 Species reproduce in different seasons or at different times of  the day

 May form hybrid on a rare occasion and can be made  

experimentally and are fertile  

 Example: species of flowers in early spring and the other in the  summer  

o Mechanical Isolation

 Structural differences between species prevent mating  

 Females copulatory organs may be incompatible -sexual organs  Example: bees may carry pollen of one species on a certain  We also discuss several other topics like Expectancy violation theory means what?

place on their bodies but the receptors on the flowers may not  

receive- pollen not transferred

o Prevention of gamete fusion

 Gametes one of species function poorly with the gametes of  another species  

 They gametes will not fuse with each other  

 Hybrids are highly unlikely

 Example: animals shed gametes directly into water, the eggs  and sperm derived from different species will not attract each  


∙ Postzygotic Isolating Mechanisms

o Hybrid inviability or infertility

 Hybrid embryos do not develop properly, they don’t survive,  hybrid adults are sterile or have reduce fertility  

 Hybrids may have abnormal sex organs / failure to form gametes  Example: leopard frogs form a group of relates species and the  fertilized eggs have problem developing  

 Example: hybridization of sheep and goats produces embryos  that die in the earliest developmental stages.  


∙     2 part-process

o Identical populations diverge- ancestral species splits

o Reproductive isolation must evolve to maintain the differences ∙     Modes of speciation

1. Allopatric

a. Geographically isolated

b. Populations appear to have differences leading to speciation dominant mode

c. Example: the little paradise kingfisher is different from each  other and geographically isolated  

2. Sympatric

a. One species splits into two at a single locality, without being  geographically separation  

b. Polyploidy: individuals with two or more sets for  


i. Autopolyploid: chromosomes arise from a single  

species- due to an error in cell division

ii. Allopolyploid: two species hybridize; one copy of the  

chromosome from each species is infertile cause it  

doesn’t pair equally for meiosis, reproduce asexually

iii. Example: parent plants produce offspring that are  

polyploidy and the offspring lived in the same  

environment but parents reproductively isolated

3. Peripatric

a. New species evolve in sub-population that colonized a new  

habitat within same geographical area

4. Parapatric

a. Populations are separated not by a geographical barrier

Genetic Drift

Two types of Genetic drift 

Genetic Bottlenecks: cause by disaster, reduce diversity 

The Founder’s Effect: allele frequencies change as a result of the migration of a small  subgroup of a population

Gene flow can be: 

Constructive­meaning­ spread beneficial mutation to other population

Constraining: can impede adaptation by continual flow of inferior alleles from other populations

Chapter 23-Systematics  


∙ All organisms share many characteristics:  

o Composed of one or more cells  

o Carry out metabolism

o Transfer energy with ATP  

o Encode heredity information in DNA

∙ Tremendous diversity of life- shared characteristics and newer molecular  sequence data

∙ Reconstruction and study of evolutionary relationships

∙ Phylogeny 

o Evolutionary tree that Hypothesis about patterns relationships among  species

o Look at how recently species share a common ancestor

 Monophyly: includes the most recent common ancestor of the  group and all of its descendants  

 Paraphyletic: includes the most recent common ancestor of the  group but not all its descendants

 Polyphyletic: does not include most recent common ancestor of  all members of the group

* early systematics relied on expectation that greater the time since two species  diverged from a common ancestor, the more different they be -evolution will be  unidirectional, convergent evolution*

The Pace of Evolution

 Gradualism

o Accumulation of small changes

o Standard view for a long time

o Ends of continuum

 Punctuated Equilibrium  

o Long periods of stasis followed by rapid change  

o Stabilizing and oscillating selection is responsible for stasis

o Ends of continuum


1. Characters can be any aspects of phenotype

a. DNA  

b. Behavior

c. Physiology

d. Morphology

2. Should exist in recognizable characteristics

3. Shared derived characteristics are informative in determining evolutionary  relationships and to determine each characteristic, use the outgroup a. Ancestral characteristic is like the presence lungs  

b. Derived characteristic is the presence of hair

* can be group as Plesiomorphic (ancestral or primitive); similarity inherited from the most recent common ancestor AND apomorphic (modified or derived);  similarity that is recent and shared only by a subset of species*

More terms need to know: 

Synapomorphy: derived character shared by clade members.  

Parsimony: favors the hypothesis that requires the fewest assumptions and it help  represent phylogenetic relationships and evolutionary events.

Phylogenesis are important to understand evolutionary biology because patterns of  relationships among species by statistical approach, molecular clock and  classification.

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