Ecology Exam 1

Ecology

the scientific study of the abundance and distribution of organisms in relation to other organisms and environmental conditions

Individual Approach

Level of Ecology; understanding of how adaptations/characteristics of an individual’s morphology, physiology, and behavior enable it to survive in an environment

Population Approach

Level of Ecology; seeks to understand what drives variation in the number, density, and composition of individuals over time & space

Community Approach

Level of Ecology; studies the diversity and interactions of organisms living together in the same place

Ecosystem Apprach

Level of Ecology; studies how energy is stored and transferred in an environment

Landscape Approach

Level of Ecology; studies the spatial arrangement of habitats and how this influences populations, communities, and ecosystems

Biosphere Approach

Level of Ecology; study of how energy and chemicals move over the Earth’s surface

Natural Selection

change in the frequency of genes in a population differential survival and reproduction of individuals that possess certain phenotypes; occurs fastest when selection & heritability are stronger

Requirements for Natural Selection

individuals vary in traits, traits are heritable, and variation in traits causes some individuals to experience higher levels of fitness

Niche

range of abiotic & biotic conditions an organism can tolerate & the organism’s role in an ecosystem

n-dimensional niche

represents the range of environmental conditions and resources availabilities in which a species can thrive

Requirement Niche

biotic and abiotic requirements for a species

Impact Niche

the effect a species has on the biotic and abiotic factors of an environment

Experiment

a scientific study with a testable hypothesis

Natural Experiment

an approach to hypothesis testing that relies on natural variation in the environment to test

Observational Studies

making deductions from patterns observed in nature; cannot equal causation

68%

percent data that lies within 1 standard deviation of the mean

95%

percent data that lies within 2 standard deviations from the mean

Standard Error

Standard deviation / sqrt(sample size)

T-test

(difference of means) / variability

Null Hypothesis

a hypothesis that is purposely wrong that is meant to be proven wrong

Alternate Hypothesis

a hypothesis written to be accepted if succeeding in rejecting the null hypothesis

5%

the percentage for an outcome to be considered improbable

Osmosis

semipermeable cell membranes allow water to cross but not allowing most other solutes

Osmotic Potential

the force with which a solution attracts water by osmosis

Hyper-osmotic

internal solute concentration is higher than that of surrounding water & fish takes up water; Fresh-water fish belong to this group

Hypo-osmotic

internal solute concentration is lower than surrounding waters & fish loses water surrounding environment; Marine fish belong to this group

Osmoregulation

mechanisms organism use to maintain proper solute balance

Turgor pressure

force that pushes cell membrane against cell walls; helps plants keep their structure

Thermal Optimum

temperature in which an organism best performs; determined by characteristics of an organism that influence the ability to function (enzymes & lipids, cell & tissue structure, body form)

Transpiration

process by which plants lose water through stomata in the leaf due to evaporation

Stomata

tiny opening in leaves that allow gases to enter/exit; let in CO2 for photosynthesis, allowing water to escape in the process that must be replenished

Matric Potential

force with which soil attracts and holds water

Saturated soil

Soil with 0 matric potential

Dry soil

soil with strong matric potential

Plant water potential

the force with which a plant tissue attracts water; passively pulls water out of the soil through the roots & throughout the plant; determined by osmotic potential and turgor pressure of plant cells; negative PWP means that plant is taking up water from roots

Light reaction

First step of photosynthesis; conversion of energy from photons into chemical energy

Dark Reaction

second step in photosynthesis; using chemical energy to make sugars from CO2

Rubisco

essential enzyme for photosynthesis; inefficient at taking up CO2, so plants must pack a lot of this enzyme into their plants cells

Photorespiration

process in which Rubisco combines w/ O2 resulting in release of CO2 & a loss of energy; tends to occur when O2 concentrations are higher than CO2, & when temperature is high

C3 Photosynthesis

simplest, most common form of photosynthesis; occurs during cool & wet conditions

C4 Photosynthesis

a form of photosynthesis that uses an enzyme that is more efficient as taking up CO2, and reduces photorespiration; disadvantage is that fewer cells are used for Calvin cycle & more energy for CO2 pump biochemistry; occurs w/ hot conditions

CAM Photosynthesis

a form of photosynthesis that allows plants to capture CO2 at night when water loss is lower; occurs w/ dry conditions

Volume Increases faster than surface area

This biological fact for animals causes large animals to lose/gain less rapidly than smaller animals, & larger animals maintain internal temperatures easier

Thermal Inertia

resistance to a change in temperature due to a large body volume

Thermoregulation

process by which an organism controls the temp. of its body

Homeotherm

organisms that maintain constant temperature

Poikiliotherms

organisms that don’t have constant body temperature

Endotherms

organisms that generate sufficient metabolic heat to raise body temperature higher than external environment; energy-intensive, and must replace lost energy w/ metabolic heat or external sources

Ectotherms

organisms w/ body temperatures largely determined by their external environment; usually poikilotherms; tend to be organisms w/ low metabolic rates & small body sizes

Blood Shunting

when specific blood vessel shut off some of an animal’s warm blood that flows to cold extremities where heat would be lost; occurs ta precapillary sphincters

Countercurrent Circulation

helps conserve heat by positioning arteries that carry warm blood away from the heart alongside veins that carry chilled blood from the extremities back to the heart; causes an equilibrium in temperature inside the circulatory system

Migration

mechanism of evolution; immigration & emigration

Mutation

mechanism of evolution; random changes in the genetic makeup of an individual

Genetic Drift

mechanism of evolution; random changes in population genetic composition due to “luck of the draw” when only some individuals pass on their genes; has larger effect in smaller population

Founder Effect

change/reduction in genetic variability when a subset of a population colonizes a new, separate area

Bottleneck Effect

reduction in size and genetic makeup of a population due to natural events or human events, decreasing overall genetic diversity

Evolution

changes in frequencies of alleles in a population across generations

Central Tendency

when data in a set is centered (mode, median, mean)

Dispersion

a measure of how spread out the data in a set is (range, standard deviation, standard error)