Ecology Midterm

Ecological hierarchy

Population, community, ecosystem, biosphere

Physical environmental influences

Extreme conditions exceeding tolerance, availability of energy and resources

Climate envelope

Range of conditions where a specific species can occur

Physiological ecology

Study of interactions between organisms and physical environments that influence survival

Stress

Environmental change that results in decreased rates of survival/growth

Acclimatization

Adjusting to stress through behaviour or physiology, typically a short term, reversible process (if long term/generational, is adaptation)

Ecotypes

Populations with adaptations to unique environments, can eventually become individual species if reproductively isolated

metabolic reactions

catalyzed by enzymes, and are destroyed by high temperature.

Izozymes

Different form of enzymes with different temperature allowances

Cell membrane

Composed of 2 lipid membranes which solidify in cold temps. Plans that thrive at low temperatures have more unsaturated lipid membranes

Ectotherms

Can’t produce own body heat and regulate through energy exchange

Endotherms

Rely primarily on internal heat

Internal heat generation as defence

Bees will swarm invading hornets and vibrate to generate heat, killing them

Ectotherms and surface area

Ectotherms exchange energy via less surface area, so their temperature can change quickly- larger Ectotherms can maintain some heat

Terrestrial Ectotherms and heating

Terrestrial Ectotherms moves round to warm up and bask (lay exposed) to warms muscles, this makes them typically more camouflaged

Microsites

Little spots that avoid freezing

Glycerol

Lowers the freezing point of muscles

Cryonics

Preservation of bodies via freezing, two frog species survive winter in the Arctic through a semi-frozen state

Thermoneutral zone

Range of environmental temperatures over which a constant basal metabolic rate can be maintained

Lower critical temperature

When heat loss is greater than metabolic production, body temperature drops and metabolic heat generation increases (arctic mammals have lower critical temps and lower metabolic activity increase)

Dormancy/Topor

When little to no metabolic activity occurs as a result of extreme temperatures, over a large period of time it can be called hibernation

Plant transpiration control

Plants can control their transpiration rates by specialized guard cells surrounding somates (leaf openings) this cooling method needs water or the plant will dry out

Pubescence

Hairs on leaves that reflect solar energy and reduce convective heat loss

Convective heat loss

Heat carried away by wind, to combat this plants stay low to the ground or grow hairs

Water stress

Plants undergo suspended animation in arid conditions, called “desiccation tolerant” and can lose up to 80% of water

Autotrophs

Organisms that generate their own energy from sunlight or chemosynthesis

Heterotrophs

Organisms that must consume other organisms for energy

Holoparasites

Entirely parasites that receive all their energy from hosts

Hemiparasite

Both get their own energy (photosynthesis) and get energy from their hosts

Chemosynthesis

Energy generated from inorganic compounds through oxidization to get electrons for forming carbohydrates

Carotenoids

Orangey colour- part of autumn leaves

Environmental controls on photosynthetic rate

Light response curves, light compensation point, light saturation point

Light response curves

Curve of the influence of light levels on photosynthesis when depicted in graph form

Light compensation point

When photosynthesis equals the exact energy lost from respiration

Light saturation point

When photosynthesis is working at its highest function, and will not increase with more light

plants in high light intensity environments

Tend to have thicker leaves and more chloroplasts- allows for higher photosynthetic saturation as well as respiration

Plant reaction to low water availability

Closes stomates, restricting co2 uptake - provides water conservation but reduces energy uptake and increases chance of light damage

Rubisco

Associated with nitrogen, its a kind of protein abundant in plants and is a key enzyme for carbon fixation, as well as preventing light damage

C4 photosynthesis

Takes more energy, but better in hotter temperatures, concentrates in bundle shells where Calvin cycle occurs

CAM

Minimizes water loss by opening stomates at night when it’s cooler, and stores during the day- example in succulent plants

Highest to lowest energy per mass

Fats, carbs, protein (nitrogen), fiber, secondary compounds

Result of nitrogen on photosynthesis levels

Higher nitrogen allows for higher photosynthetic levels. This is rare, and also increases herbivore production

Incipient species

Gradient of speciation (think crossbills in Galapagos)

Allele frequency change

Defining feature of evolution, defined more broadly as descent with modification

Gene mutation

Generates new genes (raw material) for evolution where individuals differ in their population by their phenotype

Recombination

Variance in the combination of alleles, and independent assortment of chromosomes

Directional selection

Individuals with one extreme heritable phenotypic trait that is favoured over others

Stabilizing selection

Individuals with an intermediate phenotype are favoured

Disruptive selection

Individuals with a phenotype at either extreme are favoured

Allele fixation

An allele that occurs at in a population at a frequency of 100%

Genetic drift

Random events that affect allele frequencies in a population

Gene flow

Alleles transferred from one population to another via the movement of individuals

Clines

Patterns of change in a characteristic c of an organism over a geographic region

Adaptive evolution

Evolutionary change where adaptations directly correlate with survival and reproduction, and increase with frequency

Speciation

Driven by reproductive isolation from physical barriers, mutualistic relation, or ecological interactions

Adaptive radiation

Repeated speciation events increases the number of species in a group

Big 5 mass extinction events

Late Ordovician, late Devonian, Permian-Triassic, Triassic-Jurassic, and Cretaceous

Ecosystem engineers

Animals that significantly modify their habitats/influence community structures (beavers, elephants)

Direct development

Born as little adults (no larval stage) and grow with parent

Complex life cycles

Typically more common, include larval and metamorphic developmental stages

Allocation

Energy allocated to growth, survival, reproduction, and eventually death

Raising young in low survival environments

Adults will adapt to (if they don’t already) carry or care for their offspring in environments with low survival

Phenotype plasticity

Continuous range of sizes, or discrete types called morphs (ex. Omnivore vs. Carnivore morphs in tadpoles)

Life cycle of a coral

Meiosis, fertilization, larva, polyp, and full grown stage

Spawn/sperm broadcasting

Releasing spawn or sperm into area to be fertilized (like coral)

asexual reproduction

All prokaryotes and many protists produce this way

Planktonic stage

Stage where organism is swimming larva

isogamy

the production of equal sized gametes

Anisogamy

Production of different sized gametes

Iteroparous

Reproduce multiple times in one lifespan

Semelparous

Will only reproduce once in a lifetime (like salmon)

Endosperm

Plants provides fertilized embryos in seeds with nutrient rich material

optimal foraging theory

animals will maximize the amount of energy gained per unit of feeding time - though this does not fit for eating mobile prey

Blue point - effort increase with no benefit

Red point - increasing at a constant rate

Gold - optimal point of energy expenditure for foraging

Cooperative breeding

First young stays with parents to take care of new siblings

Proximate causes

Immediate, how the behaviour occurs

Ultimate causes

Why the behaviour occurs (evolutionary/historical reasons)

Monogamy

One female one male

Polygyny

One male pairs with many females

Polyandry

One female pairs with many males

Promiscuity

Many females and males pair

Anisogamy

The large difference in energy required to make 1 egg vs. 1 sperm, makes females more particular with their partners

Exponential population growth

Unsustainable population increase by constant proportion in abundant conditions

Logistic growth

Populations first increase, then fluctuate around carrying capacity

Population outbreak

The number of individuals increase rapidly (extreme booms)

Population cycles

Populations with alternating periods of high and low abundance intervals, can vary in driving factors

Delayed density dependance

Delays in the effect that density has on population size, like predator/prey cycles

Allele effects

Populations shrink at low densities because its harder to find mates

Environmental stochasticity

Unpredictable change can cause extinction in small populations (birth and death rates differ, demographic does not)

Extinction vortex

Process drivers that intensify and accelerate extinction

Ecological footprint

Total area of productive ecosystems required to support a population

Carrying capacity

Limits imposed by a finite planet that restrict population growth

Population dynamics

Ways in which populations change in abundance over time (birth, death, immigration, emigration)

Population dynamics equation

N(t+1) = N(t)+B-D+I-E

Geometric growth

A population reproducing in synchrony at discrete Tim periods and growth rate doesn’t change, but populations increase by a constant proportion with each time period

Geometric growth equation

N(t+1) = $\lambda$ N (t) (where lambda is the geometric growth rate)

$\lambda$ = N(t+1)/N(1)

Density dependant factors

As density increases, birth rate decreases, death rate increases, dispersal rate increases

Population regulation

Density dependant factors that increase population when density is low and vice versa

Density independent factors

Temperature, precipitation, natural disasters

Logistic growth equation

DN/Dt = rN [1-n/k] where n is population density and k is carrying capacity