MACS 303 Week1

dispersion

how organisms are arranged, BLANK over distribution

dispersal

organisms leaving birthplace to colonize new area with fewer individuals to breed

process

series of actions/steps taken to achieve a particular end (living), necessary for an organism to live

Types of processes

Physical, chemical, geological

Adaption

ability or behavior (feature) that improves ecological fitness

ecology

the study of the processes/interactions that determine the distribution and abundance of organisms

Natural Selection

Evolutionary process in which individuals that possess certain

traits survive or reproduce at higher rates BECAUSE of those traits

• inc. allel frequency

Producer

An organism that uses external energy to synthesize its own food

Consumer

An organism that obtains its energy by consuming other organisms

or their remains.

population

all organisms of same species that live in a place together and interact (reproduce, predation, competition)

community

group of co-occuring, interacting populations

species richness

the number of species in a community.

Species evenness

relative abundances compared with one another.

species diversity

combination of species richness and species evenness.

redundancy

species have overlapping niches make the ecosystem more resilient to change

speciation

reproductively isolated, can reproduce with other members of the pop

species diversification rate

speciation rate - extinction rate

Hypothesis for diversifcation rate

The diversification rate is higher in the tropics because:

1) its the widest part of the Earth, with more resources/space available, more stable climate

2) Tropics have greater evolutionary time

3) higher productivity gives more resources, not always true in marine

cradle hypothesis

animals from tropics can repopulate areas were disturbances killed populations and were new species come from

net primary production

gross pp (total) - respiration

Intermediate Disturbance Hypothesis

local species diversity is maximized when ecological disturbance is neither too rare nor too frequent

• low stress, predictors dominate

• high stress, all species at risk for extinction

How Wind Cells form

differential sunlight —> pressure zones form —> warm air rises (less dense), cold air sinks —> Coriolis —> Hadley, Ferrell, Polar cells —> prevailing winds —> gyres

Seasonal climate variation??

help

Primary Producers in Marine Environment

mostly algae and some obligate marine angiosperms

algae

heterogenus group of organisms, most are oxygenic photosynthesizers, no vascular tissue, unprotected productive tissue, mostly aquatic

Primary Production

process of converting inorganic nutrients to organic matter

What limits primary production?

light, nutrients, wind, mixing, temperature, predation

• chemistry, physics, biology

intertidal zone

area above water level at low tide and underwater at high tide

neritic zone

relatively shallow part of the ocean above the drop-off of the continental shelf, approx. 200 meters

Photosynthetically Active Radiation

light of wavelengths 400-700 nm and is the portion of the light spectrum utilised for photosynthesis

• penetration depends on latitude, angle of incidence, seasons, atmosphere opaqueness

Scattering

light rays deviate from their straight path after striking particles, causing them to spread in various directions

What causes light to decrease with depth?

absorption and scattering by sea water/particles

extinction coefficient

fraction of light lost to scattering/absorption per unit of distance in certain medium

• (K)

• larger number = less penetration

quality of light

the wavelengths

What is the relationship between light and depth?

exponential decay