Ecology Exam 1

Ecology

the study of relationships between organisms and their environment, the study of ecosystems

Ernst Haeckel

coined the term ecology

Environment

a place with physician location in time and place

Biotic

living components of ecosystem

Type I error

rejection of true null hypothesis, false positive finding

Type II error

non-rejection of a false null hypothesis, false negative finding

Model

an abstract, simplified representation of a real system

What is the correct direction of the levels of organization?

individual -> population -> community -> ecosystem -> landscape -> biome -> biosphere

Climate

the long-term averages and patterns of weather features at local, regional, and global scales

Albedo

proportion of the incident solar radiation that is reflected by a surface

Net flux/ net radiation

balance between incoming and outgoing energy at the top of the atmosphere

Geostrophic flow

water is slightly less dense at the equator, and because of gravity it flows down a pressure gradient

Rain shadow

the dry area on the leeward side of a mountainous area

Interception

water is trapped by vegetation, one outcome of rainfall

Infiltration

water reaches ground and moves into the soil

Transportation

evaporation of water from the interior of plants

What are some important characteristics of water?

* polar
* solid is less dense than liquid
* hydrogen bond create strong cohesion
* surface tension and high viscosity

Stratification

in tropical waters the thermocline is a permanent feature since solar radiation heats surface year round

What is the depth of thermocline influenced by?

* wind speed
* influx of solar radiation
* wave action

Atmospheric circulation

3 cells in each hemisphere at 30 and 60 degrees where warm air sinks and then rises

The Intertropical Convergence Zone (ITCZ)

the southeasterly and northeasterly trade winds meet, is characterized by high amounts of precipitation

What affects ocean circulation?

winds, rotation, gravity, shape of ocean basins, and positions of landmasses

Equatorial upwelling

water surface water moves N and S along equator, deep cold oxygenated water replaces it

Coastal upwelling

coastal regions, winds move surface water offshore, cold nutrient rich deep water replaces that surface water

Spring tides

twice per month the gravitational pull of the sun and moon are additive, and the tidal changes during these periods are maximized

When is the density of water the greatest?

4 degrees C

How do terrestrial species deal with gravity?

Animals- internal or external skeletons

Fungi- cell walls of chitin

Plants- cell walls of cellulose

How do plants reduce water loss?

through a waxy cuticle covering plan and stomata, which opens and closes

Foliage density

leaf area

Leaf area index

area of leaves per unit ground area

Regolith

unconsolidated debris of varying depths coving unweathered rock below

Mechanical weathering

when exposed to water, wind, and temp fluctuations rock flakes and crumbles without altering composition

Chemical weathering

occurs in presence of water, O2, acids and continual acclamation of dead material, transform the composition

Leaching

movement of materials through soil

What does dark soil indicate?

high concentrations of organic matter

Soil profile

sequence of visible horizontal layers in soil, called horizons

O horizon

organic layer, ie a mid layer

A horizon

topsoil, mineral salt from parent material and humus from o horizon, darker than other layers

B horizon

subsoil, less organic matter, clays and salts, more dense

C horizon

unconsolidated material, mainly composed for parent material from which soil developed, on top of bedrock

Saturated soil

more water the pore space can hold, excess drains away

Field capacity

water fills all of the pore spaces and is help within the soil by internal capillary forces

Wilting point

soil moisture level below which plants can no longer extract water

Available water capacity (AWC)

field capacity minus wilting point

Ion exchange capacity

total number of charred sites on soil particles within a volume of soil

Colloids

negatively charged particles

Cation exchange capacity (CEC)

total number of negatively charged sites

What are the 5 edaphic processes relating to soil?

1. Laterization
2. Calcification
3. Salinization
4. Podzolization
5. Gleization

Laterization

tropical rainy conditions, rapid weathering

Calcification

evaporation and uptake of water by plants

Salinization

dry climates, salt at soil surface

Podzolization

cool moist coniferous forests (pine), acidic removal

Gleization

high rainfall, poor drainage

What does PAR stand for?

photosynthetically active radiation

Natural selection

differential success, survival, and reproduction, of individuals within a population

What are the conditions required for natural selection to take place?

heritable variation in a trait and differential survival

Fitness

the proportionate contribution made by an individual to future generations relative to other individuals in the same population

Adaptation

a heritable behavioral, morphological, or physiological trait that has evolved by natural selection

Genome

all of the DNA in a cell, in DNA molecules arranged in chromosomes

Central dogma

DNA -> RNA -> polypeptides/protein

Gene expression

Different types of tissue, different stages in life, different genes become active

Genotype

alleles present at each gene within an organism's genome

Phenotype

physical appearance of an organism for a particular characteristic

Qualitative trait

characteristic that shows a small number of discrete phenotypic categories, binary phenotype

Quantitative trait

characteristic that shows a continuous distribution of phenotypes, encoded by multiple genes, affected by environmental factors

Phenotypic plasticity

ability of one genotype to give rise to differber phenotypes under different environmental conditions

Norm of reaction

set of possible phenotypes expressed by a single genotype across a range of environmental conditions

Gene pool

sum of all the genetic information across all individuals in a population

Directional selection

distribution of phenotypes shifts to one extreme

Stabilizing selection

shift to mean value or remain stable

Disruptive selection

both extreme values of phenotype have high fitness

What processes can alter genetic variation within a population?

1. Mutation
2. Genetic drift
3. Sexual reproduction
4. Assortative mating
5. Migration

Mutation

heritable change in a gene or a chromosome

Genetic drift

change in allele frequencies (may also change genotype frequencies) as a result of random chance, smaller populations are more affected (

Sexual reproduction

random recombination of alleles

Assortative mating

individuals in a population choose mates based on phenotype, non-random mating changes genotype frequencies in the population

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●  Positive- mates more similar than expected by chance, increases homozygotes frequency

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●  Negative- mates are phenotypically less similar than expected by chance, increase heterozygotes frequency

Migration

movement of individuals among local populations

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Gene flow- movement of genetic information among populations

What are the main mechanisms that cause allele frequency change?

natural selection, genetic drift, gene flow

What are the assumptions of the Hardy-Weinberg Principle?

* random mating
* no mutations
* large population size
* no gene flow
* no natural selection

Allele frequency equation

p + q = 1

p=A

q=B

Genotype frequency equation

p^2 +2pq +q^2 = 1

p^2=AA

2pq=Aa

q^2= aa genotype

Cline

gradual measurable change in a phenotypic character or characters over a geographic region

Adaptive radiation

multiple species within a single lineage exploit different features of the environment and its resources

Genetic engineering

altering genome

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Recombinant DNA: used to alter genome, a gene from one organism is introduced into the genome of another

Ecotypes

variations within a species that are adapted to local environmental conditions

Organic

natural matter or compounds that are carbon based, also referring to food grown without artificial chemicals or pesticides

Where does photosynthesis occur?

Mesophyll cells

Light dependent

photosynthetic pigment chlorophyll absorbs light, results in synthesis of ATP from  ADP/NADPH from NADP+, convert light energy into chemical bond energy

Chlorophyll

green pigment found within the thylakoid membrane of chloroplasts, absorbs light energy

Light independent

use chemical bond energy in ATP and NADPH to incorporate CO2 into simple sugars

Net photosynthesis

photosynthesis respiration

Light compensation point (LCP)

light level where co2 uptake in cellular respiration is equal to loss in respiration, and when the rate of net photosynthesis = 0

Light saturation point

value of PAR above which photosynthesis does not increase

Photoinhibition

where rate of photosynthesis declines as PAR exceeds saturation point

Transpiration

when stomata are open, water vapor in the leaf diffuses out

Turgor pressure

force exerted outward on a cell wall by the water inside the cell

Total water potential in the plant

Ѱ = Ѱplant + Ѱosmotic + Ѱmatric

Net radiation

radiation received- radiation reflected

How do terrestrial plants lose heat?

by evaporation, but they have to have a lot of water to risk opening stomata and loosing

Boundary layer

the layer of still air or water next to the surface of each leaf