ecology exam 1

ecology

study of relationships between organisms and the environment

connected

in ecology, everything from microbes to global processes are _______________

patterns

ecology searches for _______________ or processes in nature

evolution

ecological studies work from the framework of _______________. nothing makes sense without it

trophic cascade

changes in abundances of organisms at one trophic level can influence energy flow at multiple trophic levels

biosphere

the combination of all ecosystems of the planet. all life and the area where life is found

biomes

large regions characterized by similar climate, soil, plants, and animals - regardless of where they are found

biota

sum of all living things

ecotone

boundary of biomes

climate, soil

biomes are largely dictated by ____________ and _________ - which dictate plant and animal life

climate

a region’s long term atmospheric conditions

rotation

the _______________ of the earth causes climate (seasons, movement of air, ocean currents)

long

_______-term conditions from episodic seasons create biomes

air circulation

earth’s rotation and tilt drives ___________________ patterns and consequently precipitation patterns

equator

rainforests are found near the ______________ due to the rising air

deserts

biomes that can be found just north or south of the equator, due to the dry, descending air that absorbs moisture

winds

ocean currents are driven largely by ____________ (coriolis effect)

surface

warm ____________ currents are carried by wind, carrying less dense water away from the equator and toward the poles

deep

cold _______ currents are driven by a difference in salinity across the ocean, carrying denser water away from the poles and toward the equator

soil

a complex mixture of living and non-living material

fossil

soil is like a __________, in that it has layers that formed over 1000s of years

parent

all soil is made from ___________ material - both mineral and organic

O

____ layer of soil- most superficial layer, made up of freshly fallen organic material like fallen leaves, microbes, animals. living

A

____ layer of soil- mixture of minerals, clay, silt, and sand. non-living

B

____ layer- clay, humus, and other materials leached from A, often contains plant roots

C

____ layer- weathered plant material, often rock fragments or bedrock. all other layers come from this layer

decomposes

as one layer of soil _________________, the layer below it forms

ice caps

most fresh water on earth is locked in polar ______________, so not accessible

lakes

formed from the eroding of ice sheets

littoral

the ____________ zone of a lake is where the water meets land

limnetic

the ________________ zone of a lake is the open water

lentic

___________ lake systems are standing water

lotic

__________ lake systems deal with flowing water

light

lake striation is driven by _________, based on depth

thermoclime

a layer of water that divides temperature fluctuation in large water bodies

thermal

_______________ stratification is very healthy for lakes

oligotrophic

lakes that are well-oxygenated and have lots of life

eutrophic

lakes that are oxygen-depleted and have less life

oligotrophic

if a lake turns over, it is ________________

turn over

lakes need to _____________ in order to mix nutrients and energy

nutrients

high levels of P, or having too many _______________ leads to a decline in the number of species in a lake

watershed

streams and rivers are fed by ______________ from adjacent landscape

1st

______ order streams have a very small watershed, they have a certain depth, velocity, width

2nd

______ order streams have at least 2 1st orders, or there is enough watershed to make it a certain depth, width, etc.

riffle

section of a river that has rapids because of rocks

run

section of a river that has smooth water because there are no more rocks

pool

region of a river that is the calmest, comes last

benthic zone

horizontal region of a river that comes between the ground and water, has the most biological activity

phreatic zone

horizontal region of a river that holds everything up, made of up rocks

hyporheic zone

horizontal region of a river that is the ground water and surface water interaction

position

the structure of the biological community is predictable based on ____________ within the stream

leaf litter

organic material that feeds energy of rivers and streams

lower

the higher up the number is in the stream order, the _________ its dependence of leaf litter as a nutrient

lower

_________ stream order are more species diverse because there is less nutrients, which leads to more innovative organisms and more diverse ecosystems

intertidal zone

area of the ocean where the tide ebbs and flows

shoreliens

the most biologically diverse area of an ocean

estuary

semi-salty water where fresh water flows into ocean water

bigger

____________ estuaries do not lead to better chances of survival for salmon

population

natural selection is a mechanism of evolution at the _________________ level

phenotypic plasticity

variation among individuals as a result of environmental influences - not caused by a change in genes

heritability

proportion of phenotypic variation attribute to genetic variation

tool box

organisms have a genetic ______________ that is passed down and is triggered depending on environmental conditions

fitness

the number of genes an organism contributes. no kids = no ____________

alleles

a higher frequency of _________ means something is selecting for that

offspring

organisms produce more _______________ than can survive

sexual selection

choosing a mate based on certain physical characteristics

sexual dimorphism

different appearance in males and females

non-survival

if ______________ related characteristics are used in mate selection then the frequency of the preferred traits should increase over time

variations

what determines who lives and who dies is based on the ________________ they possess, those with the best traits survive

mutation

the basis of all new traits is random _______________. a new trait can’t occur without this

sex cells

mutation is important to evolution as it occurs in ________________, thus it is heritable

immigration

migration into a population

emigration

migration out of a population

gene flow

migration allows genes from one population to mix with those of another, leading to _______________

genetic drift

fluctuation of gene frequency by chance, effect is greatest in small populations

neutral theory

theory that the overwhelming majority of evolutionary changes at the molecular level are not caused by selection - but rather random fixation of neutral mutants

natural selection

neutral theory is the driving force of evolution, _______________ just fine-tunes it

molecular

phenotypic evolution is occurring at different rates, but _____________ evolution is constant through time

alleles

Hardy and Weinberg looked at how ___________ are affected by various population characteristics

mating

one of the assumption of HW is that _____________ is random

natural selection

one of the assumptions of HW is that _________________ is not operating on populations

gene flow

one of the assumptions of HW is that there is no ______________ between populations - migration is not introducing new alleles

negligible

one of the assumptions of HW is that mutations are ____________

forces

HW analyzes allele frequencies across generations, taking away evolutionary ____________ to see which traits are being selected for

evolution

HW is what would naturally occur without ______________

directional selection

selection for an extreme phenotype. ex: antibiotic resistance

stabilizing selection

selection for a central or average phenotype. ex: human baby weight

disruptive selection

selection for both extremes of phenotype and selection against the central phenotype

species

groups of interbreeding populations connected by gene flow

ring species

species where distributions form a ring, but overlap at ends. connected just enough for there to be gene flow, and there is no reproductive isolation

chronospecies

different stages in the same evolving lineage that existed at different points in time. ex: horseshoe crabs

rules

speciation requires _______ that determine species

biological

the _________________ species concept defines a species as a group of organisms that can successfully interbreed. this is the legal definition of a species

phylogenetic

the _________________ species concept defines a species as a group of organisms that occupies the tip of a “tree branch”

morphological

the ________________ species concept defines a species based on characteristics usually applied to extinct or fossilized specimens

allopatric

_____________ speciation occurs by geographic isolation, species will evolve separately if they are isolated by space and time

sympatic

________________ speciation occurs by specified niche, species will evolve separately because they adapt to different resources and prefer different things

tectonic plates

oceans islands form from the movement of _________________ upwelling land area to create an island

endemic species

species that are only found in one place, very localized to their location

inland

____________ islands are created when species become isolated by habitat type, they eventually stop interbreeding