Ecology Flashcards
What is ecology as a study?
- the study of organism-environment relationships
- one of the most divers and interdisciplinary sciences
What may occur when one organism is destroyed? Why?
Ecology indicates the links between everything, nothing is isolated, everything is interconnected
- the destruction of one organism can lead to the destruction of other organisms
What are 3 reasons why ecology is important?
- provides information about the benefits of ecosystems and sustainable uses of the earth’s resources (for farming, construction, sustainability, etc)
- allows us to predict the consequences of human activity
- helps find solutions to burning issues ie: habitat destruction
What is an ecosystem? What is the biosphere?
Ecosystem: Includes all organisms in an area and the physical environment in which they interact
Biosphere: Highest level of ecological organization, can be viewed as the global ecosystem (includes all living things on planet : bacteria, animals, plants, etc)
How does one distinguish a biome?
Biomes distinguished primarily by their predominant plants and are associated with particular climates
Describe the ecology of warblers case study
Prediction: 2 species with identical ecological requirements cannot coexist due to competition, cannot live together indefinitely
- 5 warblers in spruce forest found to coexist via resource partitioning: eat on different sections of the tree
- suggested that aggression between species maintains feeding zones
Describe a large scale case study of ecology
- Lakes turning green (eutrophication)
-Algae was growing due to excess nutrients but which nutrients - lab experiments were inconclusive, needed a whole lake
- lake 226: part of lake with added Phosphorus turned green coming from household detergents - communication allows ban, water quality improved
What is eutrophication?
Process by which excess algae grows due to extra nutrients (typically phosphorus) residing in the water
What did Darwin discover on his trips to the Galapagos?
- every island had related species and each species traits varied among islands
Describe evolution
process that changes populations of organisms over time
- descent with modification
What is Darwin’s theory of natural selection?
- more offspring are produced each generation that can survive
- heritable variation in traits among individuals in population
- some individuals have greater fitness, which become more common in the population over subsequent generations
What is fitness?
Ability to survive and reproduce
- greater fitness traits more common and frequent
Who is Gregor Mendel?
- monk who studied garden peas
- discovered characteristics pass to offspring in genes
What is the basic unit of heredity?
Genes.
Describe genes
- portion of a DNA molecule and the basic unit of heredity
- exist in different forms called alleles
- dominant and recessive
What is the modern synthesis theory
- Darwin and Mendel’s theories complemented each other perfectly, revolutionized biology
What is the cause of phenotypic variation?
- combined effects of genes and environments causes variation
–> Phenotype = genotype + environment + (G x E interaction)
What is phenotypic plasticity ?
variation among individuals in form, function, or physiology ad a result of environmental influence
What are distinctive ecotypes?
- distinct form or race of a plant or animal species occupying a particular habitat
Why might plant species differ dramatically in one elevation to another?
Clausen found evidence of adaptation by ecotypes to local environmental conditions
Describe the Potentilla Glandulosa variation?
- 3 main gardens of plant clones at different elevations
- garden experiment revealed potential genetic differences among populations
- ecotypes present, plant’s variation increases based on environment
What is an ecotype?
a population (or subspecies or race) that is adapted to local environmental conditions.
- - unique plants adapted to a local environment
- specific traits made for unique environment
Review the genetic variation and heritability equation
What are two processes by which evolution may occur
- natural selection or random processes (genetic drift)
What can genetic drifts cause?
- gene variations to disappear completely / reduce genetic variation
- rare alleles to become more frequent
What is the Hardy Weinberg principles?
If strict conditions true (e.g., no selection, random mating, infinitely large populations) allelic variation in a gene will be maitnained
What are the major forms of selection?
- stabilizing, directional, disruptive
What is stabilizing selection?
- impedes changes in a population by acting against extreme phenotypes and favouring average phenotypes
- small and greater fitness becomes low, phenotype remains the most common
What is an example of stabilizing selection?
- ural owl hatching success: lowered fitness in individuals who lay small and large eggs
What is directional selection?
- directional selection leads to changes in phenotypes by favouring an extreme phenotype over others
What is an example of directional selection?
Soapberry bugs : soapberry bugs in FL have shorter beak, in central US longer
- beaks correlated with fruit size
What is disruptive selection?
- Creates bimodal distributions by favouring two or more extreme phenotypes over the average phenotype in a population
- phenotypically diverse,
What is speciation?
- natural selection and genetic drift change gene frequencies: in combo with physical and ecological processes and over time evolution of new species may occur
What is a species?
- multiple definitions
- most commonly defines using Mayr’s concept: a group of actually or potentially interbreeding populations which are reproductively isolated from other such groups
(must be able to breed together)
What is hybridization driven extinction?
- introduced species interbreed with native species leading to the lost of the native species’ distinct genetic identity
What is the morphological species concept?
- classification of organisms belonging to the same species based on conserved morphological features
- this concept may be useful when organisms do not reproduce or are extinct/only know by fossils
-a concept that characterizes a species based on its structural features, like body shape.
What is the biological species concept?
- when populations of organisms are able to interbreed and produce viable, fertile offspring are classified as belonging to the same biological species
What is the phylogenetic species concept?
- defines species based upon evolutionary history and phylogenetic similarity
what may cause new species?
Physical and ecological processes interact with selection and drift to produce new species
- ie: environment and genes can cause phenotypic variation - leading to new species
What is allopatric speciation?
- occurs when a single population becomes spatially subdivided into multiple subpopulations
- exchanging genes stops because of distance/isolation
What is parapatric speciation?
Occurs when a population expands into a new habitat within the range of its parent species
- extreme change in habitat followed by interbreeding
What is sympatric speciation?
- Occurs when a single population forms genetically distinct subpopulations with no spatial isolation
- new species evolves from a single ancestral species while inhabiting the same geographic region
Label/describe the images for allopatric, parapatric, and sympatric speciation
Do sympatric speciation new species breed with the former species?
No!
Why would a bee sting someone even if it will die?
- worker bees wish to ensure their genes are passed on by protecting the hive: a form of altruism, natural selection favours
What is behaviour? What causes it?
- Behaviour is the observable response of organisms to internal or external stimuli
- causes focus on genetic and physiological mechanics
- real reason is to improve reproductive success
What causes behaviour? What is its primary focus?
- based on genetic and physiological mechanics
- focus on its effects on reproductive success
What is behavioural ecology?
The study of social relations (the interactions between organisms and the environment are mediated by behaviour)
What mediates the relationship between organisms and the environment?
Behaviour
What is sociobiology?
Branch of biology concerned about the study of social relations
What is the scientific study of behaviour called?
Ethology
Can natural selection act on behaviour?
- yes! Natural selection selects for behaviour to promote reproductive success
- natural selection can work on all aspects of an organism (behaviour, phenotype)
Give an example of natural selection working on behaviour
- a single gene alters the role of a honey bee: the value fo foraging and hive building conditions depend on local conditions
- bees that are active foragers are likely less fit than bees that don’t forage until later
- another example may be prides of lions who have social benefits
What is inclusive fitness? Who introduced the concept?
- Hamilton introduced
- individuals overall fitness is determined by its survival and reproduction plus the survival and reproduction of its relative (who the individual shares genes with)
Why might an animal be less interested in protecting a baby unrelated to them?
- not genetically related, wish to preserve their genes
- that being said, animals are still likely to protect young of others, but infanticide may also occur as an act of selfishness
What is the selection for helping relatives called? What is it?
Kin selection
–> An evolutionary strategy that favours the reproductive success of an organism’s relatives, even at a cost of the organisms own survival and reproduction
-> ensure the survival of genes!
Why might an organism sacrifice itself to preserve its relatives?
- to ensure the survival of genes they both share
What is inclusive fitness a combination of?
- combination of direct and indirect fitness
inclusive fitness works to preserve actor’s personal reproductive success as well as kin
What is direct and indirect fitness?
- direct fitness affect: actor’s own reproductive success
- indirect fitness effect: the impact on the reproductive success of social partners, weighted by the relatedness of the actor to the recipient
What are the 4 main classes of social interaction? Who are they between?
Between donor and recipient, can have positive or negative impacts for those involved
- cooperation, selfishness, altruism, spite
Provide an example of spite please.
- parasitoid wasp
- sterile soldier wasps attack relatively unrelated brother larvae so the genetically identical sisters have more access to food
Which social interactions might natural selection select against? Which ones might it select for?
- spite and altruism have negative fitness consequences for the donor
- cooperation and selfishness have positive donor fitness consequences
What is altruism? Provide and example
- an act that benefits the recipient but harms the donor
- the red squirrel adopts offspring of another squirrel (expends energy for the donor, the recipient is benefitted)
What is the goal of most altruistic acts?
- to benefit the individual’s close relatives or kin
Why might an organism take care of its young if it costs energy?
- an act of altruism: offspring have copies of their parent’s gene so when parents take care of their young they are helping the survival of their own genes
- these genes continue on, and are therefore favoured by natural selection
What is group selection?
- individual acts counter to own interest for betterment of group
- criticized as inconsistent with evolutionary understanding
Why is group selection criticized as a theory?
- Because it goes against evolutionary understanding: why would an individual reduce its own well being, natural selection might be expected to go against that
Does altruism present in all situations?
no, altruisms role is actually debated - but known to occur in some circumstances
- some ecologists accept that individual gain is more likely to be selected for than group selection (resulting in behaviour like infanticide)
Why might altruism be a point of contention for some?
- natural selections leads us to expect animals to behave in ways that increase their own chances of survival and reproduction, not of others
- altruism puts animals at a select disadvantage than those who act selfishly
What is the reasoning for why altruism has not been eliminated by natural selection?
May have evolved by a progress between group selection
What is Hamilton’s rule?
- rB>C
- study the coefficients and the math plz
What is sociality?
- the fundamental change in relationships among individuals that comes with group living
- generally positive relationships, ‘worth it’
What is sociality generally accompanied by?
- cooperative feeding, defence of the social group, restricted reproductive opportunities
- cooperation generally involves exchanges of resources or other forms of assistance
What is eusociality? What are the 3 major characteristics?
- more complex level of sociality
- 3 major characteristics :
- individuals of more than on generation living together
- cooperative care of young
- division of individuals into non-reproductive and reproductive castes
What are the two forms of castes? What are they a result of?
Reproductive and non-reproductive castes found in eusocial groups
What are cooperative breeders?
- groups of adults cooperate in producing/rearing offspring including not their own
What are the benefits for helpers associated with cooperative breeding?
- inclusive fitness
- inherited territory
-kin selection
Describe the example of African Lions and sociality
–
How did eusociality evolve?
- kin selection may play role: in leaf cutters workers may be more related to other workers than to their own offspring
- ecological constrains: work required may demand more complex social behaviour, limited resources/mating prospects, etc
What behaviour does natural selection favour?
- behaviours that increase the inclusive fitness of individuals
What are trade-offs? What term is associated?
- If organisms use energy for one function, energy for other function is reduced = the principle of allocation
What are life histories?
- the sequence of events related to survival and reproduction that occurs from birth to death
What is the principle of allocation?
- how an organisms allocated energy within a segment of its overall energy budget
- leads to trade-offs between functions such as number and size of offspring
What is allometry?
The study of scaling between body size and various biological functions
Which animal shows more variation in life history than any other group?
- fish show the most variation in life history!
What does fecundicity mean?
- the number of offspring produced by an organism to produce viable, fertile offspring
Describe the darter population study in relation to gene variance
- Turner and treadler found darter populations that produced many small eggs showed less difference in allelic frequencies than populations producing few, large eggs
- proposed larvae from larger eggs hatch earlier: do not drift as far, and don’t disperse as greatly
- results in greater gene isolation and rapid gene differentiation
- smaller larvae lead to greater gene flow
Which size darter has greater gene flow? What does this represent?
The smaller larvae
- these are the consequences of life history trade-offs in darters
- more incubation time = more gene flow ??
Which two factors influence seed size and population?
Seed dispersal mode and plant growth form
What are the 4 recognized plant forms?
( Westoby )
- Graminoids: grass and grass-like plants
- Forbs - herbaceous non-graminoids (little or no woody tissue and persisting for a single growing season)
- Woody plants: woody thickening of tissues
- climbers : Climbing plants and vines
**Woody plants and climbers produce 10x mass of seeds
Which plants produce greater seed mass?
Plant forms Climbers and woodyplants: produce 10x the seed mass of forbs
What are the 6 seed dispersal strategies?
- unassisted: no specialized strucutres
-adhesion: hooks, spines, barbs - wind: wings, hair, resistance structures
- ant: Oil surface coating (elaisome-oil which sticks to ants)
- vertebrate: fleshy coating (aril)
- scatter-hoarded: gathered, stored in caches
What is the relationship between seed mass and number?
Negative relationship: greater mass, smaller number
What is the conclusion about seed size in areas of high disturbance and high stress?
- small plants producing large number of small seeds appear to have an advantage in areas of high disturbance
- large plants with large seeds produce fewer seedling but more capable of surviving environmental hazards due to deep rooting (more nutrients/grounding)
Which plants would do best in areas of high stress?
Small plants (forbs, graminoids) that produce smaller seeds tend to do better in high stress areas
Why might larger plants do better in areas of high disturbance?
- climbers and woody plants produce large, but limited number, of seeds = allows for deep rooting and more nutrient access so they are less impacted by disturbance