Biology - Speciation, Mass Extinction, and Prokaryotes

Genetic Isolation

When there is a barrier to gene flow isolating 2 populations within a species within a species

Genetic Divergence

When mutation, natural selection, and genetic drift occurs in an isolated population 

Species 

An evolutionary independent population/groups

Biological Species Concept 

The main criterion is reproductive isolation 

Prezygotic Isolation 

Successfully prevents the mating of individuals of different species 

Post-zygotic Isolation

The hybrid offspring between the individuals of different species doesn’t survive or reproduce

Morphospecies Concept

The criterion is the identification of differences in size, shape, and more

Polymorphic Species

Species that exhibit two or more distinct phenotypes

Cryptic Species 

Organisms that have similar/identical phenotypes but are genetically distinct

Phylogenetic Species Concept

Identifies species based on the evolutionary history of populations

Monophyletic Group

An ancestral population and its descendants

Synapomorphy

A trait that is found in certain groups of organisms and common ancestors, but is missing in more distant ancestors

Systematics

The discipline of biology that characterizes and categorizes relationships among all organisms on earth

Taxonomy 

The practice of describing, naming, and classifying individual species

Allopatry

Populations that are geographically separated

Allopatric Speciation

Speciation that begins with geographic isolation

Dispersal

The movement of individuals from one place to another

Vicariance

The physical splitting of a habitat, often from chance or catastrophes

Biogeography

The study of how species and populations are distributed geographically

Molecular Formula

Compact formula that only indicates the numbers and type of atoms in a molecule

Structural Formula

Indicates which atoms in a molecule are bonded together

Ball-And-Stick Models

Provides the 3d shape of molecules and often indicate the relative sizes of the atoms involved

Space-Filling Models

Accurately depict the relative sizes of atoms and their spatial relationships

Microevolution

Evolution observed at the population level

Sister Groups

Two descendants split from the same node

Node

Represent hypothetical common ancestors before splitting events

Parsimony 

The simplest explanation requiting the fewest assumptions is preferred when considering phylogenetic trees

Evolutionary Distance

Acknowledges that mere rapid evolutionary change may occur in some branches

Convergent Evolution

The independent evolution of similar traits that distantly related in organisms due to adaptation to similar environments 

Adaptive Radiation

Evolutionary process where organisms rapidly diversify from a common ancestor into a variety of forms (especially when there are new environmental opportunities)

Fauna

A collection of animal species

Microfossil

Fossilized remains of microscopic organisms, typically range from 1 micrometre - 1 millimeter

Macroscopic Fossil

Fossils that don’t require a microscope to see

Background Extinction

The lower average rate of extinction when a mass extinction isn’t occurring

Impact Hypothesis

The mass extinction of non-avian dinosaurs was caused by a large asteroid striking the earth 

Prokaryote

Cell that lacks a membrane bound nucleus

Microbiome

A community of microbes that naturally inhabits a particular area and encompasses all the genetic material contained within it

Phyla

A major lineage

Extremophile

Organisms that live in extreme habitats (heat, cold, salt, acidic, etc.)

Pathogen

Bacteria that causes diseases

Germ Theory of Disease

Infectious diseases are caused by specific microbes in the body

Endospore 

Tough, thick-walled, dormant structures formed during times of environmental stress

Antibiotic

Molecules that kill/inhibit bacteria

Biofilm

Dense bacterial colonies enmeshed in a polysaccharide-rich matrix

Bioremediation

The use of organic solvents to clean polluted sites

Enrichment Culture

A technique used to enhance the specified microorganism by giving the most favored conditions

Metagenomics 

Catalogue all genes present in a mixed community of prokaryotes

Direct Sequencing 

Based on isolating and sequencing a specific gene found in a particular habitat

Binary Fission

Asexual reproduction of prokaryotes

Transformation

Cell incorporates external genetic material from its environment

Transduction

Viruses pick up DNA from one prokaryote and transfer it to another cell

Conjugation 

When genetic material information is transferred by direct cell to cell contact 

Gram Positive

Cell wall has extensive peptidoglycan

Gram Negative

Very little peptidoglycan, and2 membranes (outer and inner)

Phototrophs

Use of light to create ATP

Chemoorganotrophs

Oxidize electron donors in the environment, sugars

Chemolithotrophs 

Oxidize inorganic molecules with high potential energy, ammonia 

Autotroph

Synthesize their own compounds from simple starting materials

Heterotroph

Absorbs ready-to-use organic compounds produced by other organisms in their environment

Cyanobacteria

A lineage of photosynthetic bacteria