4- Ecology Flashcards
Define ecology
The study of how organisms relate to one another and to their environments
What are key elements of the environment (environmental factors)?
-Temperature
-Water
-Sunlight
-Soil
Define homeostasis
Individuals must maintain a steady-state internal environment regardless of external environment
What are conformers?
Certain animals and plants are known as conformers because they conform to the environment in which they find themselves, their bodies adopting the temperature, salinity, and other physical aspects of their surroundings
What are the 3 ways in which an organism can respond to environmental change?
1) Physiological responses
2) Morphological adaption
3) Behavioural responses
What is an example of a physiological response?
-Certain species of frog will produce antifreeze, high concentration of glucose, to prevent the formation of ice crystals which would damage their cells
-This will prevent the frog’s vital organs from freezing
-A partially frozen frog will stop breathing, and its heart will stop beating
What are ectotherms?
Animals such as reptiles, fish or amphibians, whose body temperature is regulated by their behaviour or by their surroundings
What are endotherms?
Animals that can generate their own heat, have adaptions that miniseries energy expenditure
Ex: thick fur coats during the winter
True or false? Most organisms are adapted to live within a relatively narrow range of temperatures
True
What is a behaviour response?
-Many animals deal with variation in the environment by moving from one patch of habitat to another, avoiding areas that are unsuitable.
What is an example of morphological adaption in regards to water?
Camels can withstand long periods of time without any external source of water
What is an example of behavioural response in regards to water?
The beetle collects water by holding its abdomen up on a dune crest to gather condense water
Almost all ecosystems rely on energy captured by ___________. The availabilty of ________ influences the amount of life an ecosystem can support
1) photosynthesis
2) sunlight
Exception: in underwater thermal vent where life thrives on Earth’s thermal energy and dissolved elements instead of the sun
How do deciduous trees deal with the short amount of sunlight in winter?
They shed their leaves in the fall
What is soil’s impact on the environment?
The physical consistency, pH and mineral composition of the soil often severely limits terrestrial plant growth, particularly the availability of nitrogen and phosphorus.
Ex: High temperature, salts and pH limits the growth of life in Yellowstone Geyser. Only extremophiles can live in those conditions
What does natural selection lead to?
Evolutionary adaption to environmental conditions
What is Allen’s rule of reduced surface area?
Mammals from colder climates have shorter ears and limbs to limit heat loss.
What is an example of natural selection depending on populations of the same species that live in different environments?
Most Tibetan highlanders have two mutations in a gene related to oxygen uptake, but few individuals in nearly lowland populations have these mutations
(These results suggest that natural selection has driven these mutations to high frequency in very little time, it’s not been a few thousand years since the Tibetans colonized the Himalayas)
Define population
Groups of individuals of the same species that live together in the same space and time
What are 3 characteristics of population ecology?
1) Population range
2) Population spacing
3) Metapopulation
What is population range?
Area in which a population occurs
Give an example of population range
-Polar bears are well adapted for the Arctic but you won’t find them in the tropics
-The Devil’s hole pupfish have a very narrow distribution range (they only live in one water-filled cavern in the US state of Nevada)
Can population ranges chance through time?
Yes
What is population range expansion and contraction?
Population ranges can change through time
What are examples of environmental changes?
-Shifts in attitudinal distributions of trees in the mountains of southwestern North America
-During the glacial period conditions were cooler than they are now
-As the climate warmed, trees that needed colder temperatures shifted their range upward in altitude so that they continue to vie in the colder climatic conditions
What is an example of colonization of new territory?
The cattle egret expanded is range across an ocean, from Africa to South America, probably on strong winds.
The egret continues to expand its range northward in America
What is an example of human effect on the colonization of new territory?
By altering the environment, humans have allowed some species to expand their ranges.
Coyotes began expanding their range in 1900s.This was likely aided by an expansion of human agriculture, forest fragmentation, and hybridization with other species (wolf and dog)
What are dispersal mechanisms?
-seeds can be dispersed by the wind
-seeds can adhere to the fur of animals
-seeds in fleshy fruit can be eaten and pooped elsewhere
What are population spacing patterns?
Individuals in populations exhibit different spacing patterns
What are the 3 types of spacing patterns?
1) Clumped spacing
2) Uniform spacing
3) Random spacing
What is clumped spacing and what is an advantage of it?
-Social interactions can lead to clumped distributions
-Many species live and move around in large groups
-May also represent uneven distribution of resources, like food, which i common in nature
Advantage: increases awareness and defence against predators. Decreases energy cost of moving through air and water
What is uniform spacing?
-Uniform spacing within a population may often, but does not always, result from competition for resources. (Example of trees competing for light in a forest)
-In animals, uniform spacing often results from behavioural interactions (ex: Royal Penguin competing for space to incubate their egg)
What is random spacing?
-Individuals within populations do not interact strongly with one another
-rare, can be difficult to determine between random or largely clumpy
What is metapopulation?
-comprises distinct populations that may exchange members
-usually occur in areas in which suitable habitat is patchily distributed and is separated by intervening stretches or unsuitable habitat.
What is source-sink metapopulations?
Areas in which some habitats are suitable for long-term population maintenance, but others are not.
What is dispersal (source-sink metapopulations)?
-Populations centre (source) send dispersers to surrounding areas (sink).
-Small populations send fewer dispersers and receive more migrant
-Individual populations may become extinct (disease,environmental disaster, loss of genetic variation)
What is metapopulations impact on range?
-continuous colonization of empty patches prevents long-term extinction.
-in source-sink metapopulations, the species occupies a larger area than it otherwise might.
Metapopulation example sing Glanville fritillary butterfly
-200 populations became extinct, but 114 empty meadows were colonized.
-local population’s extinction is due to small population size, low resource availability (flowers), and lack of genetic variation within the population
-None of the populations is large enough to survive for long on its own, thus this butterfly needed the continued existence of a metapopulation network, which new populations are continually created and existing populations are supplemented by immigrans
What is demography?
The quantitative study of populations, it examines how a population changes size over time.
What are factors that change a population size?
1) Birth rate (b): the number of live births per time
2) Death rate (d): the number of deaths per time
3) Immigration (i): the number moving in the population per time
4) Emigration (e): the number leaving the population per time
What is the rate of population increase formula?
R= (birth rate - death rate) + (immigration - emigration)
Population growth can be influenced by the population’s ___ ratio
Sex
Number of births are directly related to the number of _______
Females
The number of _____ usually don’t affect the birth rate since _____ can mate with several ______.
1) males
2) males
3) females
Note: exception for monogamous species, where the number of males is important
What is generation times?
The average interval between birth of an individual and birth of its offspring
Population with _____ generations can increase in size more quickly than populations with ______ generations
1) short
2) long
Generation times is positively correlated to ____ _____
Body size
Does small size always mean short generation time?
No.
For example, Newts are smaller than mice but have considerably longer generation times
What is age structure?
Determined by the numbers of individuals in different age groups
What is cohort?
A group of individuals of the same age (born in the same period)
Each cohort has:
1) Fecundity rate
2) Mortality rate
What is fecundity rate?
Defines as the number of offspring produced according to time
Because different cohorts have different fecundity and death rates, ___ ________ has a critical influence on a population’s growth
Age structure
Population with a large proportion of ____ tend to grow rapidly because an increasing proportion of their individuals are at_______ age
1) young
2) reproductive
Populations with a large proportion of _____ individuals tend to decrease, since only a small fraction of individuals are at _______ age
1) older
2) reproductive
Birth rates declined during the 1960s but when baby boomers became parents, they generated a _____
Baby boom echo
What are life tables?
They tabulate the fate of a cohort from birth until death, showing the number of offspring produced and the number of individuals that die in each time period
According to life tables:
The population will grow if it’s _1
The population will stay the same if _1
The population will decline if _1
1)>
2)=
3)<
What are the types of population demography and dynamics?
Type 1: Survivorship throughout life is high then drops quickly (ex: humans)
Type 2: Even chance of death throughout lifespan (ex: hydra)
Type 3: High death rate early in life (ex: many plants, insects, sea turtles and oysters)
Natural selection favours traits that…
Maximize the number of surviving offspring left in t he next generation by an individual organism
What 2 factors affect the number of surviving offspring left in the next generation by an individual organism?
1) how long an individual lives
2) how many young it produces each year
Why doesn’t every organism reproduce immediately after its own birth, produce large families of offspring, care for them intensively, and perform these functions repeatedly throughout a long life?
Not enough resources available.
Organisms allocate resources either to current reproduction or to increasing their prospects of surviving and reproducing at later life stages
True or false? Increased fecundity in birds correlates with lower mortality?
False. It correlates to INCREASED mortality.
Species that raise more offspring per year have a higher probability of dying that year
What happened when eggs were added to the nests of collared flycatchers?
There was a decrease in clutch size the following year.
Removing eggs resulted in the increasing of the following year’s clutch size.
Douglas trees that produce more cones increase its current reproductive success, but it also…
Grows more slowly because the number of cones produced is a function of how large a tree is. This diminished growing will decrease the number of cones it can produce in the future
In terms of natural selection, the number of offspring produced is not as important as…..
How many of those offsprings themselves survive to reproduce
(Bigger offspring have a greater chance of survival. Producing many small offspring may result in very low survival rates)
Why do long-lived species delay reproduction?
-When the costs of reproduction are high, lifetime reproductive success may be maximized by deferring reproduction to enhance growth and survival rates.
Advantage: juveniles gain experience before high cost of reproduction
Why do short-lived species reproduce early?
-When the cost of reproduction is low, individuals should produce as many offspring as possible because there is little cost
-Time is important; delay may mean no offspring
What is semelparity?
Life history of annual plants, most insects and some animals focus all their reproductive resources on a single large event and then die.
What is iteroparity?
Life history of organisms that produce offspring several times over many seasons
What is biotic potential?
-The rate of population increase (r) when conditions are ideal for this particular specie (food, water, temperature, etc.)
-The maximum population growth rate for a species (rmax).
-Assume that the net immigration and emigration are equal (e=i)
-THE BIOTIC POTENTIAL OF ANY POPULATION IS ALWAYS EXPONENTIAL even when the rate of increase remains constant
What is carrying capacity (K)?
The maximum number of individuals that the environment can support
What happens if a population overshoots the carrying capacity?
The population will decrease until it reaches it
What factors affect population size through time?
1) Density-dependent: factors that affect the population and depend on population size
2) Density- independent: Other factors, such as natural disasters, affect populations regardless of size
What causes the decreased birth rate and increased risk of death when population approach their carrying capacity?
Competition of resources
Predators often focus their attention on high density prey population, which results in…
Increasing rates of mortality as populations increase
What increases rates of mortality in highly dense populations (involving the environment)?
They can lead to an accumulation of toxic wastes in the environment
How is birth rate affected in highly dense populations?
It makes resources limited so females aren’t able to produce as many offsprings
What is an example of negative effect on growth rate (density-dependent)?
-At high density, rodents become antisocial, fighting more and breeding less
-Crowded populations, the population growth may decrease because of an increased rate of emigration of individuals attempting to find better conditions elsewhere
What is an example of a positive effect on growth rate (density-dependent)?
-Allee effect: positive feedback loop between population density and growth rate
-Some species may rely on large groups to deter predators or to provide the necessary stimulation for breeding activities
What two factors generate a cyclical pattern in population size for density-dependent?
-Food (plants)
-Predators
What are external environment aspects that limit the rate of growth of a population?
-Cold winters
-Droughts
-Storms
-Volcanic eruptions
-Fire
What are the two types of adaption to resource availability?
1) K-Selected Populations
2) r-Selected Populations
What are characteristics of K-Selected Populations?
-Near the carrying capacity, the resources become limited and thus the cost of reproduction is high.
-Natural selection will favour individuals that can compete and utilize resources efficiently.
-Lower reproductive rates, as organisms wait longer to reproduce and produce fewer, larger offspring
-Adapted to thrive when population is near its carrying capacity
What are characteristics of r-Selected Populations?
-Population far below carrying capacity, resources abundant
-Costs of reproduction are low
-Selection favours individuals with the highest productive rates
What are the K-selected traits that humans have?
-Small amount of offspring
-Late reproduction
-High degree of parental care
What allowed humans to escape logistic growth?
The Industrial Revolution and technical advances in agriculture and medicine
What is a community?
-All species that live together in a specific place
-The different species that live together have made any complex adjustments to community living, evolving together and forging relationships that give the community its character and stability
What are two key roles in community?
1) competition
2) cooperation
What is an example of community?
The myriad of species that inhabit a tropical rainforest are a community, as are the species that live in a desert oasis
What are the characteristics of community?
1) Species richness
2) Species diversity
3) Primary productivity
What is species richness?
Number of species found in a community
What is species diversity?
It combines richness with evenness, taking into account how many of each species there are
What is primary productivity?
The amount of organic matter produced through photosynthesis
Why/how does community composition change across landscapes?
Community composition usually changes gradually across landscapes as some species appear and become more abundant, while others decrease in abundance and eventually disappear
What is an example of communities changing over space and time?
-Tree species in the Santa Catalina Mountains of Arizona along a geographic gradient running from very dry to very moist.
-Species can change abundance in patterns that are for the most part independent of one another
-Tree communities fall on a continuum, one merging into the next, rather than representing discretely different sets of species.
What are ecotones?
-Regions of transition between two biological communities (ex: normal soil to serpentine soil)
-Environment changes abruptly and changes the community
What is an example of ecotones?
In the western United States, certain patches of habitat have serpentine soils. This soil has high concentrations of nickel, chromium, and iron and low concentrations of copper and calcium. Comparison of the plant species that occurs on different soils shows that distinct communities exist on each type, with an abrupt transition from one to the other over a short distance.
What is an ecological niche?
The niche of an organism occupied is the total of all the ways it uses the resources and interacts with its environment. It’s the match of a species to a specific environmental conditions.
What does the niche of a species depend on?
-biotic factors
-abiotic factors
Which affect the ability of a species to survive and endure Species will evolve to adapt to a niche
What are examples of biotic conditions?
-food availability
-predators
What are examples of abiotic conditions?
-space utilization
-temperature range
What is a fundamental niche?
-Entire niche that a species is capable of using, based on physiological tolerance limits and resource needs
What is a realized niche?
-Actual set of environmental conditions, presence or absence of other species, in which the species can establish a stable population
What are the 4 types of community interactions?
1) Competition
2) Predation
3) Herbivory
4) Symbiosis
What are the two main types of community competition?
1) Intraspecific competition (within a specie)
2) Interspecific competition (between species population (two species attempt to use the same resources and there is not enough to satisfy both)
What is interference competition (in interspecific competition)?
Physical interactions over access to resources, such as fighting to defend a territory or displacing an individual from a particular location.
What is exploitative competition (in interspecific competition)?
Consuming the same resources
What is competition exclusion?
Occurs when individuals use the same resources, resulting in lower fitness for both species (-/-)
What is resource portioning? (Competition solution)
-When the niche is subdivided to avoid direct competition with one another
What are sympatric species?
Species that occur together
How do sympatric species often avoid competition?
By living in different portions of the same habitat or by using different food or other resources
Where may the pattern of resource portitioning result from?
Can result from natural selection causing initially similar species to diverge in resources used to reduce competitive pressures.
What is an example of resource partitioning (Darwin’s finches)?
-Allopatric birds, each living on their own island, have bills of similar size
-Sympatric bird, on islands where they are living together, the two species have evolved breaks of different sizes, one adopted to larger seeds and the other to smaller ones
What is the important consequence of competitive exclusion?
1) If competition for a limited resource is intense, then either one of the species will drive the other to extinction
2) The species will evolve differences that reduce the competition between them
What is predation?
-It’s a +/- interaction that occurs when one species, the predator, kills and eats the other, the prey.
- Predators have large effects on prey and vice versa
What is the relationship between predators and preys in terms of population?
-When there is a lot of prey, the predator population will increase, which will decrease the number of prey and thus with time will decrease the number of predators. This repeats in a cycle
How do starfish allow other species to thrive?
They eat barnacles, which allow other species to thrive instead of being crowded out by the explosive population of barnacles.
What is predation and coevolution?
-Predation provides strong selective pressure on the prey population.
-Features that decrease the probability of capture are strongly favoured.
-Coevolution ‘’arms race’’ may ensue
What are the types of prey adaption?
1) Chemical defenses
2) Defensive coloration
3) Mimicry
What is chemical defense ad give examples?
Used by plants and animals to prevent predation
-Poison-dart frogs produce toxic alkaloids in the mucus that covers their brightly coloured skin
-Monarch butterfly have toxic cardiac glycosides
What is an example of coevolutionary arms race?
=An arms race in a predator-prey interaction
-The newts have developed a powerful tetrodotoxins (TTX) to protect itself against predators. TTX binds to the sodium ion channel of the neuron and induces paralysis
-The garter snakes are the only major predator of this newt, since they have evolved a resistance to TTX.
-In response, toxins produced by newts are 100x more powerful than necessary to kill any other predator, but snakes match its resistance to TTX.
What is defensive coloration and give examples
-Poisonous species can harbour vibrant colour to warn predators of their toxicity
-Camouflage or cryptic coloration can help nonpoisonous animals blend with their surroundings
What is mimicry?
Mimicry allows one species to capitalize on defensive strategies of another.
-Resemble distasteful or poisonous species that exhibit warning coloration.
What is bastesian mimicry?
-Mimics look like distasteful species
What is muellerian mimicry?
Unrelated but poisonous species come to resemble one another
What is herbivory?
-Can be considered as a type of predation
-It’s a +/- interaction where an organism (herbivore) eats parts of a plant or algae
What is plant adaption?
Has led to the evolution of plant mechanical and chemical defences and consequent adaptions by herbivores
What is symbiosis?
-Two or more kinds of organisms interact in often elaborate and more or less permanent relationships.
-Potential for coevolution
What are the 3 major types of symbiosis?
1) Mutualism
2) Commensalism
3) Parasitism
What is mutualism (symbiosis)
Interspecific symbiosis in which two species benefit from their interaction (+/+)
Give examples of mutualism (symbiosis)
-The clownfish feeds on small invertebrates that harm the sea anemone and the fecal matter from the clownfish provides nutrients to the sea anemone. The clownfish is protected from predators by the anemone’s stinging cells ,to which the clownfish is immune.
-Bullhorn acacia as a mutualistic relationship with ants that lives in to hollowed-out thorns. The ants act as a defence mechanism, protecting it against harmful insects, animals or humans. The tree supplies the ants with protein-lipid nodules and nectar.
What is commensalism (symbiosis)?
-Interaction that benefits one species, but neither harms nor helps the other (+/0)
-Commensal interactions are difficult to document in nature because any close association between species likely affects both species, if only slightly.
What is an example of commensalism (symbiosis)?
-An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain or from debris accumulating around it.
What is parasitism?
A +/- symbiotic interaction in which a parasite derives its nourishment from a host, which is harmed in the process
What are examples of parasitism (symbiosis)?
-Brood parasites are organisms that rely on others to raise their young. The brood parasite manipulates a host, either of the same or of another species, to raise its young as if it were its own, using brood mimicry (ex: eggs that resemble the host’s)
-A flatworm that lives in ants as an intermediate host with cattle as its definitive host. The flatworm changes the behaviour of the ant and causes it to climb to the top of a blade of grass to be eaten with the grass.
What are keystone species (ecological niche)?
-Specie that has a strong or wide-reaching impact far out of proportion to its abundance.
-Removal of a keystone species has substantial ripple effects
What are examples of keystone species?
-Sea otter eat urchin. Their disappearance will have a wider effect by the over grazing of kelp by the urchin.
-Beavers construct dams and transform flowing streams into ponds, creating new habitats for many plants and animals.
What is succession?
How community plants evolve to respond to disturbances
What is pioneering and climax?
Pioneering: plant populations pave the way for successive populations
Climax: populations exist when succession has stabilized
What are the 2 types of succession?
1) Primary succession
2) Secondary succession
What is primary succession?
-Occurs on bare, lifeless substrate
-Organisms gradually move into an area and change its nature
What is secondary succession?
-Occurs in areas where an existing community has been disturbed but organisms still remain
-Occurs on preexisting soil
