Ecology

University of Guelph - 2nd Year Ecology

why does climate change cause fish to live deeper underwater

they go deeper underwater to find a suitable temperature

what happened to the Cuyahoga River in Ohio between 1868-1969

the river caught on fire 13 times

what did the Cuyahoga river disasters spark

the Clean Water act and environmentalism in the USA sparked by Mayor Carl Stokes, which cleaned up the river and it now has excellent water quality

what is the levels of biological organization

individuals → populations → communities → ecosystems →

what are the two definitions of ecology

• study of how organisms interact with one another and their physical environment

• study of the processes influencing the distribution and abundance of organisms

what type of change is ecological succession

a community-level change over long periods of time

how often does the microbiome in guts of bears change

seasonally - between hibernation and summer

holobient

assemblage of a host and other species living in and around it, which together forms one ecological unit

exclosure experiment

see what type of vegetation could exist without an animal species (by not allowing that certain species to access a space)

science

thought of as a collection of facts and knowledge made to understand the world

taxonomy

branch of science concerned with classification of organisms

what are the different classification groups in taxonomy

morphological, behavioural (such as reproductive and seasonal), ecological/geographical

what’s the first step in the scientific method

observation

when was the term ecology first used

in the 1860s by Haeckel, a german scientist

mechanism

a system of causally interacting parts and processes that produce one or more effects of phenomena

niche

range of environmental conditions (abiotic and biotic) and resource use that allows a species to persist and reproduce

such as max-min temp, water, interactions with other species, soil, environmental conditions, etc.

what is the range front rate that Ixodes Scapularis moves per year

rate of 46 km/year

extremophiles

organisms that are able to live in extreme conditions

what is the warmest temperature that bacteria can live in

121 degrees C

autotroph

produce their own food, requires sunlight or organic compounds

heterotroph

rely on consuming other organisms

mixotroph

produce their own food AND consume other organisms

tradeoffs

the compromises that organisms make in allocating limited resources to different aspects on their biology, behaviour, or physiology influencing fitness or adaptability to conditions

ecozone

relatively large area of the earth’s surface with distinct environmental conditions

why can’t any organism be adapted to all conditions?

because of tradeoffs

fundamental niche

the dimensions that a species could survive in principle

realized niche

the dimensions in which a species actually survives and reproduces (takes into consideration factors like predation and interactions with other species)

what are some reasons that a species is absent from an area

• it hasn’t arrived yet (diffusion)

• is dispersal-limited

• selects against that habitat

• is excluded by predators or competitors

• cannot tolerate abiotic conditions

diffusion

the gradual spread of movement of species or populations from one area to another over time (natural expansion of a species’ geographical range)

dispersal

the movement of individuals or propagules (seeds or spores) away from their original location to establish new populations in different areas

what are some ways that dispersal can occur

• active methods (walking, swimming)

• passive (blowing in the wind, drifting in water)

• animal mediated / human mediated (like ticks)

dispersal limitation

constraint imposed on colonization or distribution of a species due to the inability of individuals or propagules

habitat selection

the process by which organisms, all of humans, animals and plants, choose and occupy specific habitats that suit their needs for survival, growth and reproduction

what are the two types of factors that influence habitat selection

proximate factors and ultimate factors

proximate factors

• immediate, direct influences

• temp, humidity, food availbiltiy

• associated with physical and behavioural effects

ultimate factors

• long term influences

• competition, predation, mating, etc.

eco-tolerance

ability of an organism to endure under certain environmental conditions

does the fundamental niche or the realized niche depend on the biotic factors of the ecosystem?

realized niche

niche overlap

multiple species share similar ecological requirements

species range

geographical area where individuals of a species can be found

vagrancy

phenomenon in ecology whereby an individual appears far from it’s normal species distribution

holarctic

encompasses the northern regions of the world, composed of the Neartic (north american) and Paleoarctic (asia/europe)

what is the difference between a habitat and a niche

a habitat is a physical area and a niche is a set of conditions

range contraction

change in the range of a species that would limit other stressors

what is population growth dictated by

the scarcest resource

limiting factor

the environmental factor that is the scarcest and restricts the growth, distribution or abundance of organisms in that ecosystem

Liebig’s Law of the minimum

rate of a biological process is limited by that factor in least amount relative to the organism’s requirements

Shelford’s Law of Tolerance

• distribution of a species is often controlled by that environmental factor for which the organism has the narrowest range of tolerance

acclimation

reversible, rapid, physiological or behavioural adjustments made by an organism in response to changes in environment

niche construction

process through which individuals, through activities and behaviours, actively modify and shape their environment

what are some examples of niche construction

• beavers building dams to increase water presence

• earthworms modify soil content

• coral reefs create structures

narrowest range of tolerance

distribution of a species is often controlled by the environmental factor for which the organism has the narrowest range of tolerance

range shift

when the geographical distribution of a species changes its location

range expansion

species increases geographical distribution, usually by moving into new areas where it was not previously found

range construction

occurs when a species reduces its geographical distribution, either by withdrawing from certain areas or through local extinction

redistribution

process of shifting or reallocating the resources, organisms, and ecological components in a given area or habitat

where are many species moving in response to climate change

closer to the poles, and in regions of higher elevation

what is special about Lake Baikal

• world’s oldest, largest and deepest lake

• was formed when tectonic plates moved apart and the area filled with water

• has more than 23% of the world’s fresh surface water

endemism

species that is native to and exclusively found in a single geographical area

what is a species that is endemic to Lake Baikal

the nerpa (a type of seal)

what is a cosmopolitan species

present and common in many areas (such as rats, pigeons, etc.)

what are the five important characteristics of population distribution

• geographical range

• abundance

• density

• dispersion

• dispersal

dispersion

spatial arrangement of a pattern of individuals in a given area or habitat

dispersal

movement of an individual away from where they were born to another location where they reproduce

clumped dispersion

population is more abundant in certain spots (usually where resources are)

uniform dispersion

evenly spaced out individuals, possibly due to territorial or repulsing by animals

random dispersion

no specific pattern or order

allelopathy

• an example of uniform dispersion

• individuals release chemicals into environment that deter the growth or development of other nearby organisms

what is the difference between abundance and density

abundance is the total number or individuals in a species within an area, and density is the total number of individuals per unit area of volume

quadrat

a square is closed off in an ecosystem (perhaps 1m by 1m) and the ecosystems in the square are observed

transect

make a line in an ecosystem, someone walks down the line and writes down everything they see

mark-recapture

mark individuals, release them and recapture to see the numbers of both types of individuals, using math formulas to estimate population size

semelparous

reproduce only once in a lifetime

iteroparous

multiple reproductive cycles in their lifetime

what are some things that individuals spend energy on

maintenance, activity, reproduction, growth

principle of allocation

when resources are devoted to one use, they cannot be allocated to another

r-selected organisms

• “live fast”

• more offspring

• faster growth

• shorter lifespan

give examples of r selected organisms

rats, fish, etc.

k-selected organisms

• “live slow”

• fewer offspring

• slower growth

• longer lifespan

give examples of k-selected organisms

whales, elephants, primates etc.

intrinsic growth rate

the maximum rate at which the population can grow under ideal conditions

what does Nt represent

the population size at time “t”

what would the value of λ be if there was no change in a population over time

1

would a large population grow faster or slower than a smaller one?

faster

what are the two main types of limits for populations

density dependent factors and density independent factors

density dependent factors

become more important as the population size increases

density independent factors

affect the population size regardless of its density

carrying capacity

maximum number of individuals of a species that can be supported by the available resources in a particular environment

what is population growth eventually constrained by

density dependence

name four biotic factors

competition, predation, parasitism, disease

name four abiotic factors

temperature, precipitation, sunlight, pH

when does increased intraspecific competition often occur

at higher population densities

overshoot

lead to a decrease in birth rates and an increase in death rates, which causes a die-off

Allee effect

growth rate and survival of a population increases as population density increases, potentially due to finding mates, cooperative behaviours, predator satiation, resource availability, and niche construction

give 2 examples of species that have the Allee effect

• schooling fish

• cicadas

what is the most common equation for density dependence and what shaped curve does it produce

logistic equation, creates an s-shaped curve

why are the sable island horses a good example for anaylzing growth and death rates

it is an isolated and remote environment, meaning any population effects have a large impact on the community

what are the four factors in the BIDE model of population dynamics

Births

Immigration

Death

Emigration

population fluctuations can be

regular - tied to seasonal changes in environment

irregular - non-seasonal changes in environment

cyclical - intrinsic factors, species interactions

monophonic damping

a smooth approach to carrying capacity