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67 Cards in this Set

  • Front
  • Back

Newly Human created Ecosystems

Modifying/intruding into established ecosystems/webs

- humans becoming intermediate or definitive hose because of new interaction with organisms

ex. dams & irrigation, industrialization & human comfort, transportation & travel, food production

What is a parasite?

Lives in or on a host, gets nutrition and causes damage


The living together of different organisms

Trophic levels

where an organism fits into a food chain/web


parasites inside a host

ex tape worm


lives outside a host

ex. ticks


parasites of a parasite

ex. sealous

Molecular parasites

transposable elements; segments that replicate themselves and stay in chromosome

ex. viruses

Definitive host

the host that the parasite reaches sexual maturity on/in

intermediate host

host the parasite undergoes developmental and/or morphological changes in/on

ex. prey of a definitive host


micropredators that transmit infective stages from one host to another

ex. mosquito

transport host

host that serves to transport the parasite; no development of parasite occurs; may be obligatory often to bridge an ecological or trophic gap

ex. tadpole


animals that are normal hosts for parasites that can also affect humans

(these diseases are called zoonotic)

ex. HIV, Ebola, Malaria

Indirect life cycle

more than one host is require for the parasite to complete its life cycle

direct life cycle

requires only one host


reproducing at high rates to compensate for lack of sight/brain --> increasing chances of survival


physical and function unity of heredity


the combination of alleles that an individual carries


the suit of traits an individual exhibits (how an organism perceives for selection)

extended phenotype

when the genes from one individual impact the phenotype of another

(parasites can manipulate host phenotype to aid in survival and/or transmission to next host) --> change in coloration


natural selection can act upon any heritable trait that increases the chance for survival or transmission


change in allele frequency over time


degree of damage a parasite causes its hosts, especially in regards to the reduction of the host's fitness


evolutionary change of populations through time, within the species level

(shorter time scale - mutation, selection, drift, immigrants)


evolutionary change above the species level. The creation of biodiversity (longer time scale)

(mutation, selection, drift, immigrants, time)


Any genetic change; the source of genetic variation

- arise through replication


differential survival and reproduction

(best genes get passed on; without variation, species would go extinct)

Genetic drift

random change in allele frequency due to sampling a finite number of gametes (sampling error) - less variation with fewer gametes

effects: variance in allele frequences across populations increase; with much fewer numbers, variation is much less and can lose genetic variation

Optimal strategy

The phenotype that increases the fitness the most given the environment

Evolutionary stable strategy

a complex strategy that, when adopted by the majority of individuals, can not be taken over by any other strategy


Estimating evolutionary relationships among organisms

(tree = hypothesis of the evolutionary relationships between taxa)


Most common recent ancestor


group that contains all descendants of most recent common ancestor


Some but not all form most common ancestor


Do not share common ancestor, must go back to root of all


shared, derived trait in a monophyletic group

(allows you to build a tree) ex. spots


Fragmentation of widespread ancestral distribution by the appearance of a new barrier


movement across a pre-existing barrier


Study of the interactions between organisms and between organisms and their nonliving environment


a group of organisms of the same species living and interacting in a particular area


different populations of different species in a defined habitat


all living organisms and nonliving components of an environment in which they interact

Distribution pattern

how organisms distributed in given geographic space

(random- plants, clumped - herds, uniform- penguins)


localized patches of individuals together forming a population

geographic range

distribution of species, collective occurrance of populations

Space fragmentation

Pond with frogs with parasite --> little gene flow/migration if pond of frogs is isolated (population of parasite forms)

- introduction of dragonfly complicates

Host species fragmentation

Pond with frogs with parasite --> parasites can live in more than one host, can infect a toad too (population of parasite in frog and population in toad, alternation of host an occur, success of one over the other)

- if toad dies out, parasite adapts to frog

Host individual fragmentation

Fragmentation in a specific host: toad can represent a subpopulation of a whole population of toads in a pond

- each host can contain a subpopulation of parasites


ensemble of parasites of same species inhabiting a single host individual


ensemble of parasites of the same species inhabiting a population of hosts of a particular species


ensemble of parasites of the same species inhabiting populations of two or more host species

Meta population

ensemble of all interconnected populations of a species of parasites within all host species

(same parasite across different habitats in an area on an given host species --> multiple ponds)

Sink vs. Source

Sinks = less productive, dead end

Source = allow adaptation and evolution

If xenopopulations become more isolated from each other, speciation of parasite can occur


Interacting populations of different species in a defined habitat


the ensemble of parasites of all species infecting an individual host


An ensemble of parasites of all species infecting a defined population of a particular host species

Compound community

ensemble of parasites of all species infecting geographically close populations of several host species so that these parasites interact to a certain degree


Parasite induced loss of fitness; loss in ability to reproduce/pass on genes

--> not Pathogenicity: changes in the host caused by the parasite

Cost of virulence

Host-Induced loss of fitness(parasite has interest in not bearing too much loss of virulence but hosts wants parasite gone)

Host resistance

reducing the changes of parasite having successful encounter with the host

- selecting for/development of new defense mechanisms

Red Queen hypothesis

Parasite locks on to the most common host rather than the rare hosts; gives the rare host advantage of reproducing while common host #s decrease, when common host dies out parasite adapts to rare host

- cyclical evolution

Reproductive barriers

- hybrid species: if two species were to mate, hybrid would be sicker and more susceptible to species; less defense capabilities --> keeps species from mating and allows speciation

ex. Mice, mallards and ducks

Parasite arbitrage

the effect that parasites can have on competition between free-living species

Interhost competition

Many parasites can affect more than one host (parasites generally have different infection frequencies and intensities on different species)

- hosts can have differentiated sensitivity

Parasites maintaining or increasing biodiversity

1. leveling competition fields

Successful species get infected, gives change for species that are better at resisting parasites but worse at gathering resources a chance. Example: Red flour beetle and Confused beetle (red flour = dominant, so more infected but confused has better resistance)

Example 2: great tit and blue tit --> great tit lays fewer eggs but has greater resistance; blue tit dominant - when parasites infect both, blue tit more disadvantaged

Human mediated examples

Spanish colonization: Europeans introducing new diseases and killing 90% of native mortality rate

European eels: major food source; gall parasite in gills of fish got into eels; brought down native population when eating eels

Plague in Iran: wild gerbils vs. cropland gerbils --> wild gerbils resistant, crop gerbils sensitive; when introduced to crop gerbiles, can infect humans

Parasites driving distribution patterns

Deer and Moose --> keeps populations separate