Exam 2 Flashcards
Species
A group of organisms that exchange genes within the group, but cannot do so with other groups
Biological species concept
Species are classified through reproductive isolation
Morphological species concept
Species are classified through morphological traits
Phylogenetic species concept
Species are classified through evolutionary history
Synapomorphy
A trait found in certain groups and their common ancestor but is missing in more distant ancestors
Speciation
The formation of a new species
Allopatric speciation
Geographic isolation that creates new species
Dispersal
Movement of individuals from one place to another
Vicariance
Physical splitting of a habitat
Sympatric speciation
Speciation occurs between populations in the same geographic area
Sympatry
Populations live in the same geographic area
Extrinsic factors
Disruptive selection due to environmental difference or mate preference (outside the organism)
Intrinsic factors
Chromosomal mutations (inside the organism)
Polyploidy
Condition of possessing more than two complete sets of chromosomes
Autopolyploidy
Mutation results in the doubling of chromosome number and all chromosomes come from the same species
Allopolyploidy
Parents of different species mate and an error in mitosis occurs
Phylogeny
Branching evolutionary history of related species
Phylogenetic tree
A graph that allows us to visualize phylogeny
Systematics
Discipline of biology that characterizes and classified the relationships among all organisms on earth
Branch
A line represent a species or other taxon through time
Root
Most ancestral branch of a tree
Tip
Endpoint of a branch, representing living or extinct species
Outgroup
A taxon that diverged before the rest of the taxa that are the focus of the study
Node/fork
A point within the tree where a branch splits into two or more branches, represents the most recent common ancestor
Polytomy
A node that depicts an ancestral branch dividing into three or more descendant branches, usually indicates insufficient data were available to resolve which taxa were more closely related
Paraphyletic group
An ancestral populations and some (but not all) of its descendants
Polyphyletic group
Share similar traits but does not include the most recent common ancestor
Ancestral trait
A character that existed in an ancestor
Derived trait
A modified form of an ancestral trait found in a descendant
Homology
When two organisms share a trait due to common ancestor
Homoplasy
When similar traits evolve independently in two or more lineages
Convergent evolution
Independent evolution of similar traits in different species due to similar environmental conditions or ways of life
Anagenesis
When an original species is transformed into a different species over many generations
Cladogenesis
Pattern of branching in which an ancestral species gives rise to two or more species
Parsimony
The most likely explanation requires the fewest steps
Fossil record
All fossils that have been found in earth and described within scientific literature
Fossil
Any trace of an organism that lived in the past
Extant species
A species living today
Geologic time scale
A sequence of named intervals that represent the major events in earths history
Transitional feature
A trait in a fossil species that is intermediate between ancestral and derived species
Genetic homology
Similarity in DNA, RNA, or amino acid sequences due to inheritance from a common ancestor
Developmental homology
Similarity in embryonic form or developmental processes due to inheritance from a common ancestor
Structural homology
Similarity in adult organismal structures due to inheritance from a common ancestor
Ecology
Study of how organisms interact with each other and their environment
Organismal ecology
Study of how morphological, physiological, and behavioral adaptations increase fitness in a particular environment
Population ecology
How the number and distribution of individuals in a population change over time
Community ecology
Asks questions about nature and the consequences of species interactions
Ecosystem ecology
Study of how nutrients and energy move among organisms and through the surrounding atmosphere, soil, and water
Biosphere
a thin zone surrounding the earth where all life exists
Global ecology
Study of the effects of human impacts on the biosphere
Climate
Prevailing long term weather conditions in an area
Weather
Short term conditions of temperature, precipitation, sunlight, and wind
Hadley cell
The area between the equator and 30 degrees north and south of it
Mud-latitude cell
The cell above the Hadley cell
Season
Regular, annual fluctuations of temp, precipitation, or both
Gyres
Cyclical ocean currents that move warm water to more northern latitudes and cold water to tropical latitudes
Biome
Regions characterized by distinct abiotic characteristics and dominant types of vegetation
Littoral zone
Water along the shore shallow enough for plants to take root
Limnetic zone
Water that receives enough light for photosynthesis but is too deep for plants to take root
Distribution
How organisms are arranged over space
Species distribution
Where that species can be found geographically
Performance
Any trait that impacts fitness
T0
Optimum temp for survival
CTmin
Minimum temp for survival
CTmax
Maximum temp for survival
Tolerance breadth
All the temps in which an organism can survive
Niche
An organisms place in the environment
Ecological niche
The limits for all important environmental features within which individuals of a species can survive, grow, and reproduce
Fundamental niche
Abiotic factors
Realized niche
The portion of the fundamental niche actually occupied by the species
Metapopulation
A population of populations connected by dispersal
Demography
The study of factors that determine the size and structure of populations through time
Immigration
Organisms move into the population
Emigration
Organisms leave the population
Life table
Summarizes the probability that an individual will survive and reproduce at any given interval of their life
Cohort
A group of individuals of the same age
Type 1 curve
Survivorship throughout life is high and drastically drops in old age
Type 2 curve
Individuals have the same probability of dying each year of life
Type 3 curve
Extremely high death rates in early life stages but high survival rates for individuals that make it past this stage
Fecundity
The number of female offspring produced by each female in the population
Net reproductive rate
Survivorship multiplied by fecundity
Life history
How and indivisible allocates resources to reproduction, growth, and survival
Life history traits
Traits that affect the amount of reproduction or the development of offspring
N
Population size
t
Time
r
Per capita rate of increase (birth rate- death rate)
R
Net reproductive rate
g
Generation time
Intrinsic rate of increase
When the birth rates are as high as possible or as low as possible
Nt
Population size at the end of time
N0
Population size at time 0
Carrying capacity
K- the maximum number of individuals in a population that can be supported in a particular habitat over a sustained period of time
Mutualism
Interaction from which both species benefit
Commensalism
One species benefits while the other is unaffected
Parasitism
Parasite lives on or in a host and feeds of the flesh and fluid of the host
Symbiosis
An interaction between organisms living in close physical association
Predation
One organism benefits by preying on the other, which is negatively effected
Herbivory
Animal species benefits by feeding on a plant species which is negatively affected
Competition
An interaction between individuals in which each is harmed by their shared use of a limited source
Intraspecific competition
Among individuals if the same species
Interspecific competition
Among individuals of different species
Interference competition
Direct competition in which one individual physically excludes the other from that portion of the habitat
Exploitative competition
Indirect competition in which use of resources depleted the amount available to others
Competitive exclusion
If two species require the same resources , they cannot coexist indefinitely
Niche partitioning
When competing species use different resources to reduce competition
Character displacement
Genetically based divergence in phenotypic traits results in decreased competition between species
Coevolution
A pattern of evolution in which two interacting species reciprocally influence each other’s adaptations over time
Evolutionary arms race
A mechanism of circulation that occurs in +/- species interactions. Traits that increase feeding efficiency evolve in predators. In response, traits evolve in prey that make them unpalatable or elusive
Disturbance
Any strong, short-lived disruption to a community that changes the distribution of biotic and abiotic factors
Disturbance regime
Predictable severity and frequency of characteristic disturbances in a community
Succession
Predictable pattern of community dynamics after a disturbance where species with certain life history patterns succeed each other
Pioneering species
A species adapted for growth in disturbed souls that devote most of their energy to reproduction, not competition
Dominant species
Most abundant species in a community
Keystone species
A species with a much greater impact on the distribution and abundance of the surrounding species than predicted by abundance
Species diversity
The number of species and abundance of each species
Sampling effort
How many sample are required to characterize a community
Diversity indices
A mathematical measure of diversity that takes into account species diversity and richness
Primary producers
Organisms that transform solar energy into chemical energy as sugars and carbohydrates
Gross primary productivity (GPP)
Measures the total amount of chemical energy produced within an area over a given time period
NPP
The total amount of chemical energy stored in organic material in an ecosystem (biomass)
Tropic levels
Organisms that obtain their energy from the same source
Productivity
Rate of biomass produced by growth and reproduction
Efficiency
Fraction of biomass transferred from one trophies level to the next
Biomagnification
Persistent organic pollutants ( POP’s) increase in concentration at higher levels of the food chain
Decomposes
Organisms that feed on dead organisms
Detritus
Dead animals and dead plant tissue
Bottom- up control
When the amount of nutrients, sunlight, water, and other abiotic factors determine the abundance of different tropic levels
Top- down control
When the presence of certain consumers (biotic factors) determine the abundance of different tropic levels
Tropic cascade
When the changes in top down control cause conspicuous effects toe or three links away in a food web
Nutrients
Elements that are essential for normal metabolism, growth, and reproduction
Biochemical cycle
The path an element takes as it moves as it moves from abiotic systems, through tropic levels, and back again
Soil organic matter
Complex mixture of partially and fully decomposed detritus
Humus
Completely decayed detritus, rich in humid acids
Reservoirs
Areas where elements are stored within a cycle
Flow
Processes that moves elements from one reservoir to another
Groundwater
A reservoir of freshwater stored in the ground
Aquifers
Layers of porous substrate saturated with water
