Unit 8 Ecology Study Guide

Climate

the long term prevailing weather conditions at a given place

what has the most significant influence on the distribution of organisms? What are the 4 physical factors?

climate; temperature, precipitation, sunlight, and wind

abioic

nonliving; referring to the physical; and chemical properties of an environment

biotic

pertaining to the living factors - the organisms - in an environment

what are the 3 things that influence the distribution and abundance of life

cimate, abiotic and biotic factors

rain shadow

caused by mountains and creates deserts on backs of mountains

what are the environmental differences between a north and south facing slope

south facing slopes receive more sunlight than northern facing slopes and are therefore warmer and drier

what does a forest do

it absorbs more sunlight because of its darker color and cools down temperatures through the evaporative loss of water from plants

biomes

any of the worlds major ecosystem types, of ten classified according to the predominant vegetation for terrestrial biomes

what determines biomes

physical environment for aquatic biomes and characterized by adaptations of organisms to that specific environment whereas climate determines terrestrial biomes

what are the layers of the rain forest

canopy, low tree layer, shrub understory, ground layer of beroaceous, forest floor (AKA litter), root layer

climograph

a plot of the temperature and precipitation in a particular region

disturbance

a natural or human caused even that changes a biological community and usually removes organisms from it

canopy

the uppermost layer of vegetation in a terrestrial biome

ecotone

the transition from one type of habitat or ecosystem to another, such as the transition from a forest to a grassland

what are the 2 types of tropical forest

tropical rain forest and tropical dry forest

tropical rain forest

relatively constant rainfall and 2 types and is vertically layered and animal diversity is higher than in any other terrestrial biome

tropical dry forest

6-7 months of dry season and is vertically layered and animal diversity is higher than in any other terrestrial biome

savannah

30-50 cm of rain with dry season that can last up to 9 months. temperatures vary more than tropical forests. there are many scattered trees bc of overgrazing and many have thorns to protect themselves. the dominant herbivores are termites

desert

low precipitation and temperatures vary seasonally and daily (there are both hot and cold deserts). it is dominated by low scattered vegetation and adaptations of plants include tolerance to heat and desecration, water storage, reduced leaf surface area and physical devfences and many plants carry out CAM photosynthesis

chaparral

highly seasonal climate. the dominating organisms are plants that are grasses and forms and many have adaptations to help them survive droughts and fires. large mammals graze and burrowing mammals live here

temperate broadleaf forest

cold winters and humid summers. dominant plants are deciduous trees(they drop leaves before winter in Australia) evergreen and eucalyptus are common in N hemisphere and mammals hibernate while birds migrate

northern coniferous forest

AKA taiga; the largest terrestrial biome and usually has very cold winters. dominated by cone bearing (conifers) and some even depend on fires to regenerate and needle leaves to reduce water loss

tundra

(when on top of mountains its called Alpine Tundra); is mostly herbaceous with a permanent frozen soil layer called permafrost which restricts griwth of plant roots

photic zone

the narrow top layer of an ocean or lake, where light penetrates sufficiently for photosynthesis to occur (vertical zone)

aphotic zone

the part of an ocean or lake beneath the photic zone where light does not penetrate sufficiently for photosynthesis to occur (vertical zone)

pelagic zone

the open water component of aquatic biomes (vertical zone)

benthic zone

the bottom surface of an aquatic environment (vertical zone

benthos

the community of organisms living in the benthic zone of an aquatic biome

littoral zone

in a lake, the shallow well lit waters close to shore and are shallow enough for rooted plants (horizontal zone)

limnetic zone

in a lake, the well lit open surface waters far from shore too deep for rooted plants (horizontal zone)

thermoline

a narrow stratum of abrupt temperature change in the ocean and in many temperate zone lakes

wetlands

are inundated by water at least sometimes and support plants adapted to water saturated soil

estuary

the transition zone between a river and the sea. nutrients from upstream make these among the most productive biome

lakes

light decreases in depths creating zones. temperate lakes may have a seasonal thermocline where tropical lowland lakes have it year round

what are the 2 types of lakes

ollgotrophic and eutrophic lakes

ollgotrophic lakes

nutrient poor and oxygen rich (less surface area comparatively)

eutrophic lakes

nutrient rich and oxygen poor inadequate some in sump and in winter due to high composition rates

streams and rivers

headwater streams are cold, clear, and turbulent winds downstream in larger rivers the water is warmer and more turbid because of suspended sediment

what are headwater streams

narrow channel, rocky bottoms, and switch between shallow and and deeper pools

river

wide and meandering, silty bottoms from sediments

internal zones

periodically submerged by the tide 2x daily. Oxygen and nutrient levels are high and renewed with each turn of the tide has a rocky or sandy substrate

coral reef

formed largely of calcium carbonate skeletons of coral and require high oxygen levels. require solid substrate for attachment, and animal diversity is that of tropical forests

ocean pelagic zone

vast realm of open blue water. Oxygen content is high. however nutrient levels are lower than in coastal waters. covers 70% of earths surface

marine benthic zone

consists of the seafloor. temperature declines with depth while pressure increases. Oxygen concentrations are generally sufficient to support diverse animal life

what are the producers in environments near deep sea hydrothermal vents

chemoautotrophic

dispersal

the movement of individuals or gametes away from their parent location. this movement sometimes expands the geographic range of a population or species

density

the number of individuals per unit area or volume

dispersion

the pattern of spacing among individuals with in the boundaries of a population

what are the 3 types of dispersion

clumped dispersion, uniform, and random

clumped dispersion

individuals are aggregates in patches (most common)

uniform dispersion

evenly spaced pattern that can result from direct interactions between individuals in the population. animals often exhibit this as a result of antagonistic interactions (territorially)

random dispersion

the position of each individual in a population is independent of other individuals. occurs in the absence of strong attractions or reputations among individuals

territoriality

a behavior in which an animal defends a bounded physical space against encroachment by other individuals, usually of its own species

demography

the study of changes over time in the vial statistics of populations especially birth and death rates

life table

a summary of the age-specific survival and reproductive rates of individuals in a population

cohort

a group of individuals of the same age in a population

survivorship curve

a plot of the number of members of a cohort that are still alive at each age; one way to represent age specific mortality

Type I survivorship curve

flat at the start , reflecting low death rates during early and middle life and then drops steeply as death rates increase among older age groups

Type III curve

drops sharply at the start, reflecting very high death rates for the young, but flattens out as death rates decline for those few individuals that survive the early period of die off

type II curve

intermediate, with a constant death rate over the organisms life span

exponential population growth

growth of a population in an ideal, unlimited environment, represented by a J-shaped curve when population size is plotted over time

intrinsic rate of increase

® in population models, the per capita rate at which an exponentially growing population increases in size at each instant in time

When can the intrinsic rate of increase occur

possibly when populations are introduced into new environments whose numbers were drastically reduced by an event and are rebuilding

logistic population growth

population growth that levels off as population size reaches carrying capacity

life history

the traits that affect an organisms schedule of reproduction and survival

K-selection

selection for life history traits that are sensitive to population density (selection for traits that are advantageous at high densities)

R-selection

selection for life history traits that maximize reproductive success in uncrowded environments

density independant

referring to any characteristics that is not affected by population density

density dependant

referring to any characteristic that varies with population density

intrinsic factors

those operating within an individual organism

population dynamic

the study of how complex interactions between biotic and abiotic factors influence variation in population size

metapopulation

a group of spatially separated populations of one species that interact through immigration and emmigration

pathogens

an organism or virus that causes diseases

zoonotic pathogen

a disease causing agent that is transmitted to humans from other animals

vector

an organism that transmits pathogens from one host to another

evaportranspiration

the total evaporation of water from an ecosystem, including water transpired by plants and evaporated from a landscape, usually measures in millimeters and estimated for a year

species area curve

the biodiversity pattern that shows that the longer the geographical area of a community, the more species it has

disrurbance

a natural or human caused event that changes a biological community and usually removes organisms from it. disturbances such as fires and storms play a pivotal role in structuring many communities

non equilibrium model

a model that maintains that communities change constantly after being buffeted by disturbances

intermediate disturbance hypothesis

the concept that moderate levels of disturbance can foster greater species diversity than low or high levels of disturbance

ecological succession

transition in the species composition of a community following a disturbance; establishment of a community in an area virtually barren of life

primary successtrion

a type of ecological succession that occurs in an area where there were originally no organisms present and where soil has not yet formed

secondary succession

a type of succession that occurs where an existing community has been cleared by some disturbance that leaves soil or substrate in tact

species diversity

the number and relative abundance of species in a biological community

species richness

the number of species in a biological community

relative abundance

the proportional abundance of different species in a community

biomass

the total mass of organic matter compromising a group of organisms in a particular habitate

introduced species

a species moved by humans, either intentionally or accidentally, from its native location to a new geographic region

trophic structure

the different feeding relationships in an ecosystem which determine the route of energy flow and the pattern of chemical cycling

food chain

the pathways along which food and energy is transferred from trophic level to trophic level, beginning with producers

food web

the interconnected feeding relationships in an ecosystem

foundation species

species that has strong effect son its community as a result of its large size, high abundance, or pivotal role in community dynamics. these may provide significant habitat or food for other species; they may also be competitively dominant in exploiting key resources

keystone species

a species that is not necessarily abundant in a community yet extra strong control on community structure by the nature of its ecological role or niche

ecosystem engineers

an organism that influences community structure by causing physical changes in the environment

bottom up control

organisms being controlled by what they eat

top down control

organisms being controlled by what eats them

interspecific interations

a relationship between individuals of 2 or more species in a communituy

competition

a -/- interaction that occurs when individuals of different species compete for a resource that limits the survival and reproduction of both individuals. can also occur between members of the same species which is considered interspecific competitition

competitive exclusion

the concept that when populations of 2 similar species compete for the same limited resource, one population will use the resources more efficiently and have a reproductive advantage that will eventually lead to the elimination of the other population