LIFE 320 Exam 1

abiotic

portions of ecosystems that are non-living

biotic

living portions of ecosystems

parent material

layer of bedrock that underlies soil and plays a major role in determining the type of soil that will form above it

horizon

distinct layers of soil; commonly referred to by letters

leaching

process where groundwater removes substances by dissolving them and moving them down to lower soil layers

cation exchange capacity

ability of soil to retain cations

Liebig’s Law of Minimum

multiple constraints to ecosystem productivity (temp, water, macronutrients, bases, cations)

producers/autotrophs

create their own food (primary producers)

consumers/heterotrophs

obtain energy from other organisms

decomposers

organisms that break down other organisms

herbivores

eat plants

detritivore

eat dead plants

carnivore

eats other animals

omnivores

eat both plants and animals

species

compromise the biotic component of ecosystems; similar organisms that are able to reproduce

scale of organization

• species

• population

• community

• ecosystem

• biome

Four Laws of Ecology

Barry Commoner

1. Everything is connected to everything else

2. Everything must go somewhere

3. Nature knows best

4. There is no such thing as a free lunch

biome

a major ecological community, extending over a large area and usually characterized by the dominant vegetation

adiabatic cooling

the cooling effect of reduced pressure on air as it rises higher in the atmosphere and expands

adiabatic heating

the heating effect of increased pressure on air as it sinks towards the surface of the earth and decrease in volume

latent heat release

when water vapor is converted back to liquid, water releases energy in the firm of heat and warms air

albedo

the fraction of solar energy reflected by an object

hadley cells

circulation of wind near the equator; at 30 degrees north and south is where it ends and dry areas are present

coriolis effect

the effect of living on a sphere, causes liquids to curve and the sphere spins faster near equator

gyres

any large system of rotating ocean currents

thermohaline circulation

a global pattern of currents that flow as a result of variants in temperature and salinity that change the density of water

rain shadow

when a mountain has one side be wet due to the the amount of water in the air and the other side is dry as the water is dumped to the wet side

Evolution by natural selection

1. more individual s are produced than can survive and reproduce

2. Individuals vary

3. Some of the variation is heritable and leads to differences in reproductive success

microevolution

changes in the frequency of alleles or occurrence of mutations in a population (change in species today)

macroevolution

large scale changes leading to the creation of new species (creating new species); evolution at higher levels of organization including species, genera, families, orders, and phyla

punctuated equilibrium

forms can remain constant until conditions change (rapid change)

gradualism

may yield a rich fossil record with many intermediate species

transitional fossils

fossils show evidence of transition from one species to another

antibiotic resistance

some bacteria are resistant to antibiotics

vestigal features

features that remain from previous lineages

homological features

features that are shared from common ancestry

speciation

the evolution of new species

phylogenetic trees

hypothesized patterns of relatedness among different groups like populations, species, or genera; depict which groups evolved form other groups

Types of evolutionary pressures

mutation, founder effects, bottlenecks, genetic drift

reproductive isolation

the force behind speciation

directional selection

when individuals with extreme phenotypes experience higher fitness than the average population phenotype

disruptive selection

when individuals with either extreme phenotype experience higher fitness than individuals with an intermediate phenotype

adaptive radiation

diversification of an ancestral group to fill many habitats

allopatric speciation

geographic isolation

parapatric speciation

reduced genetic mixing along a boundary

peripatric speciation

isolation of habitats

sympatric speciation

creation of a new species within a geographic area, behavioral

divergent evolution

organisms diverging from parent species to become distinct species

endemic

unique to an area

biogeography

the study of biological distributions

Wallace’s line

an imaginary line that separates Australian fauna from Asian fauna

vicariance

division of population to pieces

K-T Extinction

Cretaceous Paleogene extinction (death of dinos)

island biogeography

islands closer to mainlands have more species; larger islands have more species

adaptation

traits of animals or plants that allow them to maximize fitness

structural adaptations

physical adaptations that allow for better survival or production of offspring

chemical adaptation

venom, spray, ink, toxins

behavioral adaptations

instinctive and learned (mating rituals, migrations, mate choice, food choice, hunting strategies)

life history

the schedule of an organism’s growth, development, reproduction, and survival; represents an allocation of limited time and resources to achieve maximum reproductive success

fecundity

the number of offspring produced by an organism/reproductive episode

parity

number of reproductive episode an organism experiences

parental investment

time and energy given to offspring by parents

longevity

life span of organism

r-selection

short time to sexual maturity, low parental investment, high number of offspring, short life span

k-selection

long time to sexual maturity, long life spans, low number of offspring, high parental investment

stress tolerators

herbs with a long lifespan, slow growth, long time for sexual maturity

competitors

grow fast, achieve early sexual maturity, and devote little to seeds

ruderals

grow fast, devote high portion of energy to reproduction

precocial

able to feed itself immediately

atricial

dependent upon parents for food

semelparity

when organisms reproduce only once during their life

iteroparity

when organisms reproduce multiple times during their life

annual

an organism that has life span of a year

perennial

an organism that has a lifespan of more than one year

senescence

a gradual decrease in fecundity and an increase in the probability of mortality

ecological communities

an assemblage of plant and animals populations that inhabit a particular area

natural disturbance

hurricanes, floods, tornadoes, lightening

anthropogenic disturbance

forest harvest, clearing, human-caused fires

short term responses

immediate change to ecosystem due to distributions

long term responses

longer term changes to ecosystems and the potential for recovery

equilibrium

interactions between species lead to resource partitioning and diverse communities

non-equilibrium

frequently changing conditions allow for multiple species to coexist, with none able to monopolize resources

succession

the coming of one person/thing after another in order, sequence, or course of events

ecological succession

orderly changes in the structure of communities over time

pioneer species

species that are first to occupy an area, often r-selection good disperses and able to tolerate extreme conditions

climax community

stable community that does not undergo further succession

primary succession

successional processes that follow the removal of soil; formation of new lands from lava flows and glacial retreat

secondary succession

far more common, following disturbance that does not remove the soil

eutrophication

introduction of sediment to a body of water

F.E Clements view

communities are predictable

• succession had one true climax state for every region

• super organsism with distinct boundaries

H.A. Gleason

random events help determine the composition of communities

• simply composed of interacting individualistic species without boundaries

• single climatic region could yield a variety of climax types

heterogenous habitats

disturbance large and small lead to landscapes of constant recovery

intermediate disturbance hypothesis

the most competitive species are kept in check, allowing less competitive species to build their pups

niche

range of physical/biological conditions in which a species lives and how species obtains what it needs and reproduces

ecological equivalency

when two species in different location share a niche

intraspecific competition

between members of the same species

interspecific competition

between members of different species

competition exclusion

two species cant have the same niche at the same place

fundamental niche

niche defined by the species physiology

realized niche

niche actually occupied, given constraints