Ecology and Evolution Final Exam

Competition

use or defense of a resource by one individual that limits the availability of that resource to other individuals (logistical growth, not perfect)

Resource

substance or factor that is consumed by an organism and that supports increased population growth as its availability in the environment increases

limiting resource

resource that prevents the survivorship, growth, and reproduction of organisms, even when there are other resources available

examples of resources

food, water, shelter

examples of measurable conditions

Temperature, humidity, pH, precipitation

Law of the minimum

populations will increase until the most limiting resource prevents further growth

Intraspecific Competition

members of the same species compete. Reduces resources in a density dependent manner: underlies the regulation of population size, is a process promoting evolutionary change

Interspecific Competition

different species compete. Depresses populations of both competitors: may lead to elimination of one species, thus potentially important in determining coexistence. gives the upper hand to the more efficient species

Interference competition

“Hogging” competition where competitors defend resources

Allelopathy

interference where organisms use chemicals to harm competitors

Exploitive competition

competitors drive down the abundance of a resource so others can’t live

Apparent competition

looks like competition but isn’t. 2 species have negative effect through parasite, predator, or herbivore

Niche

represents the range of conditions and resource qualities within which an individual or species can survive and reproduce

Fundamental niche

the total range of resources it can use under ideal conditions

Realized niche

the resources it actually uses within the community

Competitive exclusion principle

2 species cannot coexist indefinitely if limited by the same resource, i.e. two species cannot occupy the same niche

Niche Partitioning

natural selection drives two competing species to begin using different niches or types of resources

Symbiotic (definition)

association between 2 or more where at least one benefits from the relationship

Mutualism (definition)

association between 2 or more species where everyone benefits

Facultative mutualism (definition)

species involved can survive without each other

Obligate Mutualism

tight relationship where one dies without the other

Optimal defense hypothesis

organism allocate defenses to maximize individual fitness and the defenses are costly

Resource availability hypothesis

account for plants ability to replace grazed tissues

Coevolution

driven by predation, each species shapes the others adaptations over time 

Evolutionary arms race

how species interactions can drive natural selection

Red Queen hypothesis

species must constantly evolve (sexual reproduction) allows evolution rate to offset evolution of parasites, viruses, bacteria, predators, etc.

Predator

consumes other organisms

parasite

an organism that lives on or in another organism, but rarely kills it

Parasitoid

An organism that lives in on one host, eventually killing the host as part of its development. Mostly wasps, bees, and flies keep insect populations regulated

Pathogens/disease vectors

microscopic parasites that cause disease like abnormal condition that negatively affects organs not due to an external injury

Hemiparasite

photosynthesis but gets water from the host

Holoparasite

rely totally on the host plant (habitat, photosynthesis, water)

Kleptoparasitism

parasitism by theft 

Predators include

parasites, parasitoids, and herbivores

Victims include

prey, hosts, and munched upon plants

Commensalism

a symbiotic relationship where one organism benefits while the other is neither helped nor harmed

Amemsalism

A relationship where one organism is harmed and the other is neither benefitted or harmed

Community

multiple species interacting directly or indirectly that are connected by time and space

Clear cut communities

one area is clearly a community, distinction between communities

Ecotone

Where two communities meet

Species diversity

comparison of relative abundance of species in a community

Species richness

number of species in a community

Species evenness

comparison of relative abundance of species in a community

Diversity indicies

estimates of species diversity

Island biogeography

studies the biodiversity of isolated natural communities (how isolated environments are)

Resistance

how much a community changes due to a particular disturbance

return time

how long it takes a community to return to a stable state after being disturbed

resilience

how close the post-recovery community resembles the pre-disturbance community

Food web

many organisms living together and feeding on one another. We can draw diagrams of their feeding relationships

Food chain

a zoom on close feeding relationahips in the food web

Green Earth hypothesis

the Earth is green because predators prevent herbivores from eating everything

Bottom-up control

increase or decrease in primary producers leads to a sequence of similar (+ or -) effects to the rest of the food chain

Top-down control

the predator population (+ or -) effects the lower tropic levels that can be supported

Trophic cascade

indirect interactions between community members controlling the whole ecosystem.

Apex predator

top predator of the food chain

Primary producer

plants, algae, etc

Secondary consumer

eats herbivores/primary producers

succession

change in community through time initiated by a disturbance

Primary succession

development of communities in habitats devoid of plants and organic soil (soil with carbon)

Secondary succession

development of communities in habitats nearly devoid of plants but with organic soil

Pioneer species

first species to colonize (typically lichen or moss)

climax community

final stage in succession

Space for time substitution

uses current spacial patterns to infer how something will change over time

Scouring flooding

special case of succession, flood takes a lot of organic materials, flips over all the rocks in the environment

Lake succession

special case of succession,plants growing at the bottom of the lake, filling the lake over time with organic material

Dune succession

special case of succession,Henry Chandler Cow, the dunes and plant environment are different from one another 

keystone species

species which disproportionally affects relative abundance (population size)

Dominant species

species which affect the community through their high abundance

ecosystem engineer

an organism that significantly modifies its environment, creating habitats for other species beyond its own lifetime

Biomass

organic material from plants and animals that can be used for energy production, such as heat, electricity, and biofuels

Gene Flow

Organisms move in and out of populations.

Cryptic species

organisms that are morphologically identical/similar but genetically distinct

The Morphological Species Concept

defining species based on their physical characteristics

The Morphological Species Concept: Pros

Applicable to living and extinct organisms, to organisms no matter their reproductive mechanisms

The Morphological Species Concept: Cons

inconsistent, and not always practical (e.g. “cryptic species” or polymorphism within a species or between sexes)

The Biological Species Concept

Groups of actually or potentially interbreeding naturally populations which are morphological from other such groups 

The Biological Species Concept: Pros

Embraces idea of lack of gene flow

The Biological Species Concept: Cons

How do you evaluate “potentially” interbreeding?

The Phylogenetic Species Concept

defines species on their genetic and evoluationary history

The Phylogenetic Species Concept:Pros

Genetic testing is becoming easier and widely applicable

The Phylogenetic Species Concept: Cons

Often not practical, could more that double current estimate on current species numbers

Scientific communication

shared terms for scientists to categorize and communicate organismal research

Conservation

to track the status and diversity of populations

Phylogenetic trees

Diagram showing the evolutionary relationships among organisms or groups or groups of organisms, based on shared traits or genetic information

Tips

Each organisms grouping being show on the phylogenetic tree

Branches

between nodes and tips

Nodes

a branching point between where gene flow stops

Divergent evolution

branching into two different groups based on differing traits

Synapomorphies

a characteristic present in an ancestral species and shared by its evolutionary descendants

Sister taxa

two groups who are each other’s closest relatives.They split from the same node.

clade

(monophyletic group) organisms that share characteristics/ genetic information from common origin

What are phylogenetic trees built on?

genetic and molecular traits

Taxonomy

identifying, naming, and formally recognizing organisms according to a set of rules

Classification

arranging organisms into groups (taxa) based on shared traits/genes

Taxon

a group of organisms that is in one category of classification

Taxa

Multiple taxon

Binomial nomenclature

two-part naming with Genus and species in italics

Phylogeny

depicts evolutionary relatedness

Phylogenetic tree

organizational pattern for relatedness of different groups

Phylogenetic systematics

process of determining evolutionary relationships