BIOL 1108 Springthorpe UGA - Exam 1

Population

All of the individuals of a SINGLE SPECIES that interact

Community

All of the populations of LIVING things that interact in a place

Ecosystem

A biological community of interacting organisms and their physical environment (biotic & abiotic)

Abiotic

Non-living factors in an ecosystem

-Climate

-Temperature

-Precipitation

-Soil Properties

-Water Properties

-Disturbance Types and Frequency

Biotic

Living factors in an ecosystem

-Biodiversity

-Biomass (NPP)

-Species Interactions

-Invasive Species

-Keystone Species

What size is an ecosystem?

There is no defined size

Biome

A distinct type of geographical region defined by vegetation present

What causes changes in vegetation?

Temperature and Precipitation

Changes as elevation increases

Temp, soil quality/depth, pressure, O2 all go down. Humidity and water availability generally go up. As temperatures drop, the air is able to hold less water vapor, so we say it has higher relative humidity.

Biomes change...

As height and latitude change

Which has more biodiversity? 100 km2 at the base of a mountain vs 100 km2 of mountains?

100km2 of Mountains, more changes in biome

Old Growth Forest

•never been logged

•Not undisturbed

•Diverse forests and lots of wildlife

"Rich" Soil

lots of available nutrients for plant growth

Tephra/Ash

Rock dust, unable to hold water well or have nutrients

Which organisms reach disturbed areas first?

Animals are going to reach the area first but will be unable to survive.

Which organisms establish in disturbed areas first?

Plants (nitrogen fixing specifically)

How do plants migrate into disturbed areas?

Seed dispersal

Seed dispersal

How seeds/spores are spread away from the parent plant

Seed Dispersal Types

Wind

Expulsion

Animals

Water

Seed Coat functions

Protection from environment

Protects From getting crushed, digested, dried out, waterlogged, etc.

Thick vs Thin Seed Coat

Seeds are thinner or thicker based on energy investment from a plant. It costs energy more for plants to make a thicker seed coat (more seeds vs better seeds)

Cotyledons

the "yolk" for the little embryonic plant.

Holds food, can be a monocot or dicot

Large Cotyledon Pros

•Can store more energy

•Can last longer before sprouting (germination)

•Can grow quickly to overtop competitors before they need to tap into their own food and water

•Each seed is individually more likely to survive

Small Cotyledon Pros/Cons

•Can produce many more

•Longer distance dispersal

•BUT...Each seed has a lower chance of survival (per capita survivorship)

Larger Seeds vs Smaller Seeds

Smaller seeds take less energy to make

Larger seeds take more energy

Fitness

a measure of evolutionary success based on the number of offspring that survive to maturity by the PARENT plant. It's not about how many seeds you make, but how many survive to reproduction.

Traits that help a seed REACH first, reduce SURVIVAL probability

Traits that help SURVIVAL probability, reduce dispersal distance

What else determines survival?

Ability to acquire nutrients once the cotyledon runs out, after germination

•Germination

seed emergence

-Seed becomes seedling

Macronutrients

NPK

Nitrogen

Phosphorus

Potassium

-makes nucleic acids/amino acids

Micronutrients

Needed in small quantities to make coenzymes

Where do plants get macronutrients?

NPK all come from the soil and are taken in by the roots

C (Carbon) - By air

O2 (Oxygen) - Air and Soil

Lupine

Established in the pumice plain first

What was limiting in tephra

Nitrogen

Liebig's Law of the Minimum

Individuals:

-Individuals will grow only up to the point it runs out of a vital resource, even if there are surpluses in other categories

Populations:

-Populations will grow only up to the point that they run out of a vital resource

How many limiting resources can exist at once

1

Why Do Organisms Need Nitrogen (N)?

DNA - Nitrogenous bases (ACTG)

•Chlorophyll

•Neurotransmitters

•Proteins -macromolecules with many functions

Protein overview

-Complex molecules made of amino acids that do MANY things

-Synthesized (made) using ribosomes and an mRNA template (translation)

-Can denature (change shape) when too hot

All amino acids are composed of

•Central carbon

•Amino group (NH2)

•Carboxyl Group (COOH)

•Side Chain (R group)

Amino acids make up...

proteins

A change in one stage affects all...

Later stages

1 affects 2 3 and 4

3 affects 3 and 4, etc.

At each stage, shape is determined by

bonds and IMFs

Bonds

•"permanent" connections between atoms in a single molecule (intramolecular forces)

Types of Bonds

•Covalent (share electrons)

•Ionic (donate/steal electrons)

IMFs

Intermolecular Forces - electrostatic (charge) attractions between molecules that can vary in permanence and strength

Electronegativity

the differences that exist in electronegativity between atoms in a bond determine how much time electrons will spend around one atom or another and whether or not that bond will be polar or non-polar as a result. The higher the electronegativity, the tighter hold an atom has on its electrons.

Differences in electronegativities, even within a covalent bond can lead to...

partial charges being applied to atoms. These partial charges result in polar bonds or molecules.

Type of bond is based on the relative amount of time electrons spend around involved atoms

0-.4 - Nonpolar Covalent

.4-1.7 Covalent

>1.7 Ionic

IMFs (Non-Covalent Interactions) 1.

Dipole-Dipole

An attractive force between any δ+ in one molecule and the δ- in another molecule

IMFs (Non-Covalent Interactions) 2.

•Hydrogen Bond (H-bond)

A special dipole-dipole between a δ+ H and an O,N or F with a δ- in another molecule.

VERY important for water - cohesion, surface tension

The H is always the positive contributor

The negative contributor to an H-bond is one of those highly electronegative atoms (in biology basically always O or N)

Hydrogen Bonds Test

•Is it between molecules?

•It there a partially positive H?

•Is it connected to a partially negative something else?

Amino Acid Structure

are 3 parts to every AA. The only one that changes is the R group. (we are given aa sheet)

Disulfide Bridge

Cys Amino Acid

Always nonpolar covalent, S and S have equal electronegativity

Primary Structure Bond (1)

Primary (1o) Structure - Peptide bonds: C-N covalent bond connecting AAs (Polar Covalent)

Secondary Structure Bond (2)

coils or crimps (α-helix or β-sheet)

•Hydrogen-bonds (H-bonds) are responsible along the peptide backbone

NOT related to R Groups

Tertiary Structure Bond (3)

R-Groups determine 3o structure

IMFs, ionic bonds and sometimes disulfide bridges determine exact folding pattern

Tertiary Structure Bond (4)

IMFs, ionic bonds and sometimes disulfide bridges determine exact folding pattern

Multiple folded chains

N-cycle

Plants get nitrate from the soil via assimilation. That nitrate is present by way of bacteria that break down and decompose other organisms or generate it (eventually) from N2 through N-fixation

Most nitrogen is

In the atmosphere, but we can't break the triple bond between N2

Nitrogen Fixing Bacteria

•Bacteria are N-fixing, not plants

•Common one are rhizobia

•Also cyanobacteria, green and purple sulfur bacteria, Azobacteria, a few others

•Common plants with these associations are legumes (peas, beans, clover, alfalfa)

N Fixing Bacteria/Plant Relationship

In this relationship, lupine (or any other "N-fixing plant") gets N in exchange for sugar that the bacteria uses to fix N. The sugar (glucose) comes from photosynthesis, which the plants are able to do, while the bacteria can't. From the perspective of N-fixing bacteria, on the pumice plain they are probably carbon-limited since there isn't any carbon in the soil.

Plants without N-fixing bacteria have more energy for...

-more seeds

-growing fast

-more roots

Mutualism

•Both species benefit from the interaction

Symbiotic

Live their lives in close physical proximity (together/ touching) and evolved together

Predation

One organism kills another

Herbivory

Animals Feeding on Plants

Commensalism

a long-term biological interaction in which members of one species gain benefits while those of the other species neither benefit nor are harmed

Ex. Seed Dispersal w/ stickers

Competition

•When 2 organisms "fight" over a limited pool of resources (food, mates, nitrogen, shelter, etc.)

2 Types of Competition

•Intra-specific Competition: Between individuals of the same species

•Inter-specific Competition: Between individuals of different species

Antagonism

Herbivory Predation and Parasitism

Neutralism

0/0

Amensalism

one individual is harmed while the other is unaffected

Altruism

One organism acts to increase the fitness of another organism at a cost to itself (decreasing fitness)

Kin Selection

an organism increases the fitness of a relative at a cost to its own (ants, bees, matriphagy)

Eusociality

"Altruism" to the extreme

•Defined as:

-Division of labor/caste system

-Overlap of reproductive generations

-Cooperative care of young

-There is a "point of no return"

Facilitation

The presence of one species alters the environment in a way that enhance the growth, survival, or reproduction of another

Can be positive, negative, or neutral for the first species

Facilitation Examples

•Increased soil moisture by sagebrush in the desert - decay/wind destroy the bushes but the soil is wetter and cooler in the desert.

•Temperature / Humidity Regulation, such as an animal being shaded by a large tree while it recovers energy

•Attracting Pollinators for other plants with big showy flowers

Soil Chemistry Improvement (N-fixers) - Lupine fixing soil for other plants

Succession

is the process of development that over time, gradually and predictably changes the biological community

Climax Community

•the stage that will persist as a static ecosystem and will continuously regenerate itself (until a disturbance).

Primary Succession

Starting from bare rock

Secondary Succession

Starting with at least some soil

Sometimes Secondary Succession is referred to as Old Field Succession

Where Do We Find Primary Succession?

•Mountain Tops

•Glacial Retreat

•Parking Lots

•Granite Outcrops

Succession increases _______ over time

Complexity

Types of Complexity

•Structural Complexity

-Vertical

-Horizontal

•Soil Complexity

•Biodiversity

Horizontal Complexity

Patchiness, more heterogenous = more horizontally complex, increases with disturbance

Vertical Complexity

increases w/ succession, is a measure of the height/variation of height

Disturbance

Acts as a reset for succession, INCREASES horizontal complexity, decreases vertical

dynamic equilibrium

•an ecosystem in a constant state of flux (change) due to disturbance and succession

•Develops over time

•Contains patches in different successional stages

Forest Gaps

•Openings in a forest canopy (disturbance) where new trees can grow

Early Successional Trees

High Max GR

Low Persistence

Low Shade Tolerance

Low Longevity

Late Successional Trees

Low Max GR

High Persistence

High Shade Tolerance

High Longevity

Biodiversity

how many kinds of organisms are in a place

Intermediate Disturbance Hypothesis

•biodiversity is highest when disturbance is present but not too frequent

Why are some places more biodiverse than others?

•Time/Age (Succession and Dynamic Equilibrium)

•Ecosystem Complexity (Horizontal/Vertical and topographic)

-Mountains have high biodiversity

-Lots of climate zones = lots of species

Simpson Index (D)

1/(sum of Pi^2)

Shannon Index (H)

-(Sum of Pln(P))

Resistance

ability to prevent impacts from disturbance

-Ecosystems with high biodiversity change less

Stability

resistance and resilience contribute to fewer fluctuations in an ecosystem

Resilence

ecosystem's stability and capability of tolerating disturbance and restoring itself

Alien/Exotic/Introduced Species

•nonnative species introduced by people