Final Flashcards
What are the five interspecific interactions?
Neutral Mutualism Commensalism Predation Competition
Describe the “Neutral” type of interspecific interaction.
neither affected
Describe the “Mutualism” type of interspecific interaction. Give examples
both benefited:
Coyotes and Badgers are known to sometimes help each other hunt for prairie dogs; the coyote can chase it and the badger can dig for it
Nitrogen fixing bacteria give nitrogen to soybeans, which function as a habitat
Describe the “Commensalism” type of interspecific interaction.
one benefited, the other not affected
Describe the “Predation” type of interspecific interaction. Include the types and definitions of parasitism.
one benefited, the other is detrimental:
Herbivory
Carnivory
Parasitism: one benefited, the other got harmed (e.g., tapeworm)
Parasitoidism: a type of parasitism, but the host eventually got killed
Endoparasitoidism: a parasite that lives inside its host
-Ex: Chinese caterpillar fungus
Cannibalism (eating its own species)
Describe the “Competition” type of interspecific interaction.
mutually detrimental or hurt
What are the possible consequences of interspecific competition?
Competitive exclusion or coexistence
Define Allelopathy.
Effect of metabolic products of plants on the growth and development of other nearby plants.
Give examples of plants that exhibit allelopathy. List the types of chemicals used.
Types of chemicals: acids, bases, phenolics, aromatic cpds
Broom sedge: inhibit shrubs
Bracken fern: phenolic acids to kill conifers
Black walnut: secrete precursor to juglone, works against broad leaf plants
Bamboos: secrete phytotoxins against ferns
Define plant secondary compounds
Compounds not directly related to plant growth (Ex: phytotoxins of bamboos)
Describe the phenomenon of invasive exotic species in the Great Lakes
(competition w/ endemic spp.)
139 exotic spp. introduced into Great Lakes ecosystems; invertebrates and vertebrates. Exotic spp. have caused 68% extinction of fish species and 70% of endangered spp. in North America.
Why is difficult to find field examples of competitive exclusion or to conduct competitive exclusion experiments in the field?
Don’t know what stage they are at
Environment changes
Immigration & emigration
Genetic alterations (mutations, recombinations, etc)
Carrying capacity unknown
Life history unknown
Has already settled through co-evolution (most important)
Describe Gause’s Principle (or competitive exclusion principle) and its 3 assumptions
When two or more species coexist using the same resource, one must displace or exclude the other. In other words, complete competitors cannot coexist.
-When the niche overlaps too much only two outcomes. One or more species may start to explore other niches
Assumptions of competitive exclusion:
1 Environmental factors remained constant
2 No emigration/immigration
3 Over time, competitors genetically unchanged
These are unreasonable assumptions
What is the application of competitive exclusion principle in the reintroduction of an endangered species?
In most cases their niche has already been occupied, you must be cautious
Describe the interaction of the chipmunks in Sierra Nevada
Co-existence of different species of chipmunk through the adoption of a unique niche. Some chipmunks (Least) can live in wide range, but have home ranges restriction by aggressive other species (Yellow-pine chipmunk). The limit is defined by the most aggressive species (lodgepole)
Define character displacement
Shift in species’ morphology, behavior, or physiology as a result of natural selection resulting from interspecific competition
Compare fundamental niche vs. realized niche
Fundamental niche: free from interference from other species
Realized niche: niche of a species when part of that niche has been subtracted by competition
What is a guild? Give an example
A group of species utilizing a gradient of resources in a similar way. Ex: chipmunks in Sierra Nevada
Describe the ecological significance of the relationship between grey wolves and coyotes
In the 1600s many wolves were killed so people could settle in New England. Example of fundamental niche vs realized niche in that the niche of the coyotes changed when relieved from the pressure of the wolves. Example of Interference competition in that both populations negatively effect each other when coexisting
Describe the population dynamics of snowshoe hare and lynx
When the population of the snowshoe hare was high, the lynx population was also high; vice versa
Their predator-prey cycle was around ten years (would see a great peak in population of both the hare and the lynx at the same time every ten years)
Describe the three hypothesis about the snowshoe hare vs lynx population dynamic and the evidence that supports them
(likely a combination of all three):
Simple Predation
Conventional predator-prey cycle
Simple food limitation
Survey food abundance over ~12 years, close relationship between drop in woody browse (winter food) and drop in snowshoe hares and lynxes
In canada, a food station was put out to manipulate food availability and test this hypothesis
Fluctuating secondary compound contents
Plants (especially in winter) will create secondary compounds that are toxic to hares and will mess with their digestive function -> reduce total energy -> less energy for reproduction
Describe the predator-prey cycle
Prey population goes down as predation occurs -> less predators -> less predation -> prey population rises -> …
Clear patterns are not often seen
Why aren’t clear examples of the predator-prey cycle often seen? (3 reasons)
The prey population is density-dependent (i.e., internal regulation).
Almost every species is attacked by more than one species of predators. Most predator species attack more than one species of prey.
Long-term monitoring data not exist
What were the discussed types of defense chemicals?
Toads, snakes: peptides, alkaloids
-Destroy RBC, increase coagulation, neurotoxic
Stinkbug: volatile terpenes
What were the types of camouflage/Cryptic coloration discussed?
Flounder – match the background
Walking stick – resemble a twig
Year-old deer possess white skin spots to blend in with sunlight penetrating the forest
Describe the chemical defenses of the monarch butterfly and its relationship to blue jays
Monarch butterflies cause physiological issues in the blue jays (contractile force of the cardiac muscles), dissuading the blue jays from consuming them
What were the types of flashing coloration/shape discussed?
White-tailed deer flash their tail to warn other deer when they sense danger. The owl butterfly has fake eyes on its wings to dissuade predation, as predators normally go for the neck and the eyes of their prey, leaving the butterfly mostly intact.
Describe the two different types of mimicry: what are they? How do they work?
Batesian mimicry:
non-toxic resembling toxic
Mullerian mimicry: distasteful, mimic each other. The predators need to be exposed to only one coloration to recognize the signal
What are some behavioral defenses employed by prey species?
Redirect predators (mother bird distracting the predators by acting injured)
Scatter around (schools of small fish swim together, then scatter when a predator gets close so they don’t have time to choose a good prey
Form a concentrated formation (musk ox)
How do prey species affect the timing of their reproduction to protect against predators?
Reproduce in a very short period of time or shift timing of reproduction to avoid predators (If predators are active in day, you become active in the night; in hibernation try to avoid being present the same year their predators are active
Ex: Cicada
What are the outcomes of ingesting PSCs?
Behavioral deterrence- the animals do not want to consume the materials
Anti-biosis- reduction in growth rate, in development, stillbirth
Why do plants and animals evolve the same types of chemicals for defense?
These happen to be the most effective compounds
Define Cannibalism. In what species is it common? In what situations does it occur?
Killing and eating an individual of the same species.
Common in protozoans, rotifers, insects, frogs, fish (e.g., walleyes), birds, mammals including humans.
In what situations? Stressed populations, facing starvation
Walleyes in summer
Victims: young and small
Describe the difference between genotype vs phenotype
Genotype is the sum of hereditary information
Phenotype is the external, observable expression of the genotype; morphological expression of genes
Define Phenotypic plasticity
The ability of an organism to change its phenotype in response to changes in the environment
What are the three outcomes of natural selection of a population? Describe them
Stabilizing Selection: Favors phenotypes near the population mean; occurs in stable environments; environmental pressure on two extremes; most common type found in stable environments
Directional Selection: Favors extreme phenotypes; occurs with an abiotic or biotic selecting force; environmental pressure only on one extreme; pushes population to other extreme (Darwins medium ground finch)
Disruptive Selection: Favors both extreme phenotypes; natural force acts on intermediate phenotypes and pushes them towards the extreme; results in a population of two or more genotypes/phenotypes; 2 selection pressures → 3 groups (Papilio dardanus butterfly)
Describe genetic polymorphism
Type of disruptive selection- A discontinuous genetic variation resulting in the occurrence of several different forms of types among the members of a single species.
Describe Industrial melanism
the prevalence of dark-colored varieties of animals (esp moths) in industrial areas where they are better camouflaged against predators than paler forms
Ex: moth living in industrial manchester England had only three phenotypes (black, gray, white) when before there was a range of colors, black also came to dominate with 95+% of the population, soot coated wood and killed lichens
What is inbreeding depression? What is outcrossing depression
Inbreeding depression: reduced genetic variability, decreased fertility, loss of vigor, reduced fitness, reduced pollen and seed fertility in plants, and even death.
Outbreeding/Outcrossing is when the species is mated with unrelated individuals. Could fail resulting in offspring from crossings that are not as well equipped in their environment
Ex: Northern bobwhites (Ohio, Illinois, Pennsylvania) were in trouble, so Southern bobwhites (Alabama) were introduced and they started breeding
Big failure -> offspring from crossings could not resist cold environment (due to southern parent) and had high mortality
Describe the Founder Effect. Give an example
Effect of starting a population in a new location with a small number of colonists, which contain only a small and often biased sample of genetic variations of the parent population; a markedly different new population may arise.
Ex: migration
Describe the Genetic Drift. Give an example
Over a period of time, BY PROBABILITY some genes in a population are fixed and other alleles are lost. i.e., drifted and fixed.
Rate of genetic drift is determined by the size of the population
Ex: Northern Elephant Seals had a very small level at one point, they now lack genetic diversity
Why are insects/beetles best to study adaptations?
Insects have a high number of species and variety of adaptations
Describe Charles Darwin
On The Origin of Species (1859)
traveled to a lot of continents, islands (either far or close and small or large). He observed animals who seemed to have not have changed in many years. He also observed animals that have changed a lot. He waited almost three decades to publish his results- his family (upper class) worried about the church of England. He told his friends though
Describe Alfred R. Wallace
Introduction of Species
Studied in Amazon River and far East. Wrote a letter to Darwin talking about evolution. Darwin was shocked that someone else had similar thoughts. Wallace’s book was very similar to Darwin’s.
Describe Charles Lyell
a lawyer and a geologist
Close friend of Darwin, romantic person, invited Wallace and Darwin to present their data at a conference.
Describe Thomas Henry Huxley
Comparative anatomist, very slow in accepting Darwin’s theories. Later he became one of his biggest champion.
Henry Walter Bates
The Naturalist on the River Amazons
Studied in Amazon river area and collected more than 14,000 species, including 8,000 new species. All were shipped back to the United Kingdom. He was the first person to describe batesian mimicry (non-toxic imitate toxic).
What are adaptations a product of?
Natural Selection, ultimate end is speciation
Define epigenetics
environmental factors that influence the degree of gene expression
Why does adaptation and evolution occur?
Reproduction in a population is not random; ABIOTIC and BIOTIC factors favor certain traits, so certain individuals are more successful in reproduction than others (i.e. selective outcome).
What are the two ways to characterize species by spatial relationships?
Sympatric species- (subpopulations occupy same area)
Allopatric species- (subpopulations separated geographically)
Define sympatric species
a species in which subpopulations occupy in the same area at the same time. Have opportunities to breed.
Define allopatric species
a species in which subpopulations were separated geographically.
Once they are separated long enough, no way to know whether they can mate.
How do you determine if separated subspecies are still the same species?
To determine if they are the same species, must bring them together → allow them to mate with each other and produce fertile offspring
What is a cline? Give an example
a measurable, gradual change in population characteristics over a range of geological region. Result from adaptation of a gradual change physiologically, behaviorally, and genetically in an ecological gradient (e.g., temp, moisture, light, nutrients, etc)
White-tailed deer: 136 kg to 46 kg, from north to south
-due to temperature change, this keeps you warm
-This occurs on other species as well where subpopulations are in different areas, to ensure a good surface area to volume area
(More volume:surface area ratio=warmer animals)
What is an ecotype?
genetic strains of subpopulations adapted to its unique local environmental conditions.
- Marked discontinuities, abrupt changes (i.e., punctuated)
- Also called step clines
What are geographical isolates? What is an example?
Population that is separated from exchanging genetic material with other organisms of the same species
Salamanders in southern Appalachian Mountains form several subspecies due to barriers of rivers and mountains
Describe the two mechanisms of speciation
- Allopatric speciation (or geographic speciation):
The separation of a population into two or more evolutionary units (i.e., species) by some geographic barrier that causes reproductive isolation - Sympatric speciation (mainly behavioral speciation)
A new species may arise within a population occupying a single habitat or within the dispersal range of a population.
E.g., insects parasitic to plants
(Two major isolating mechanisms, Geographically,
Ethologically (i.e., courtship, mating behaviors))
What is adaptive radiation?
Evolution from a common ancestor to divergent forms adapted to distinct ways of life.
Ex: finches adapted to different food groups (cactus, insect, seed, fruit)
What is the definition of a community?
A group of interacting plant and animals living in a given area in the same period of time
Compare and define biomass and standing crop biomass
Biomass: weight of living materials
Unit: dry weight per unit area
How to measure? - harvest just above to ground
Standing crop biomass: Total amount of biomass per unit area in a given period of time
Unit: dry weight per unit area per year
