Ecology Exam 1

Instantaneous Growth Rate

(r) = (dN/dt)/N(t)

Fecundity Table

- A fecundity table combines the survivorship (l(x)) with the age-specific birthrates (b(x)). - l(x)b(x) = mean number of females born in each group, adjusted for survivorship = net reproductive rate R(0)

What is Ecology?

- A science built on research and understanding of how nature works. - The study of interaction of organisms with their biotic (other organisms) and abiotic (physical and chemical) environment.

d(x)

- Age-specific mortality - = The difference between the number of individuals alive for any age class (n(x)) and the next older age class (n(x+1)).

q(x)

- Age-specific mortality rate - = The number of individuals that died in a given time interval (d(x)) divided by the number alive at the beginning of that interval (n(x))

Life Table

- An account of age-specific mortality - First developed by the insurance industry in the 1650s. - Wanted to be able to predict how much longer an insured would live so that the company would be sure to collect enough in fees to cover the payoff at the time of death. This is called an actuarial table. - So, the older you get, the more expensive your insurance. - Ecologists use the same principles to predict the life expectancy of animal populations.

Individuals in Populations interact with one another:

- By competing for resources (food, space, mates, etc.) - Through intra-specific social/behavioral interactions

Birth Rate Types

- Crude birth rate - Age-Specific birth rate

Stage 3 - Stationary of Population Age Structure

- Declining birth rate - Low death rate - More people living to old age - (Shaped like a dome)

Small Scale Distribution

- Distribution is on the order of a few hundred square meters where there is little variability in environmental features. - 3 Basic Patterns: random, uniform, and clumped.

Examples of Invasive Species

- Eastern Red Cedar (native to VA, serious pest in Oklahoma) - Gypsy Moth (introduced to U.S. in 1869) - Zebra and Quaga Mussles - Kudzu (the plant that "ate" Georgia) - Hemlock Wooly Adelgid (the Adelgids feed on the Hemlocks, killing them)

Ecology Textbook and Authors

- Elements of Ecology 9th Ed (note: editions 6, 7, or 8 will do) - T.M. Smith & R. L. Smith (2015)

Measuring the Density of Small Animal Populations

- Estimate density by taking many samples and counting animals in each sample. Generally done for invertebrates - Can sample from grid, lines, sweeps with vacuum cleaners, pitfall traps, sticky traps, etc. - Can stratify samples: sample sub-habitats and keep samples separate (e.g., sample bed rock, loose cobble, and sand in a reach of stream or sample pools vs. riffles) - Ex: Sampling Feshwater systems using nets and grids, sampling agricultural pests using stick traps, setting fish traps, electrofishing.

Catadromous Life Cycle

- Ex: American Eel - The adults feed and grow in the streams, then migrate to the ocean to breed and die. Te young make their way back to the steam to feed and grow for years.

Anadromous Life Cycle

- Ex: Salmon - The salmon breed in streams and die, then the young salmon (called smolts, age 1-3 years) move to the ocean to feed and grow as an adult (for 1-8 years) then return to the stream to breed and die (known as spawning adult).

What are the two major demographic features of populations?

- Geographic Distribution - Density (abundance per unit area or volume)

Invasive Populations of Exotics

- High Reproductive Potential - No enemies (predators or diseases) - Invasives are not necessarily exotic

Stage 2 - Expanding of Population Age Structure

- High birth rate - Fall in death rate as more living in middle age - Slightly longer life expectancy - (Shaped like triangle)

Stage 1 - Expanding of Population Age Structure

- High birth rate - Rapid fall in each upward age group due to high death rates. - Short life expectancy. - (Shaped like a curved in triangle)

Why did the reindeer population crash?

- In an exponential model G = rN. - But in reality, the growth is limited by K, the carrying capacity. G = (rN)*[(K-N)/K] G = population growth r = constant growth rate N = population size (# of individuals) K = carrying capacity Basically once the population size hits a certain number it begins to decrease because there are only so many resources to sustain the population.

Indirect Control of Climate over Geographic Distribution

- Indirect control may include the climate affecting the food supply, water, or habitat. - Ex: plant populations are known to distribute themselves along moisture-temperature gradients.

Levels of Ecological Hierarchy

- Individuals (Species) - Populations - Communities - Ecosystems - Landscapes - Biomes - Biosphere I punched Connor Elliot Lee because boys.

Life Expectancy Variables

- L(x) = average number alive during age interval - T(x) = total years lived into future/age - e(x) = age specific life expectancy - s(x) = Age specific survival = 1 - q(x)

Stage 4 - Contracting of Population Age Structure

- Low birth rate - Low death rate - Higher dependency ratio - Longer life expectancy - (Shaped like a dome, with the bottom curved in more)

Type III Survivorship Curve

- Mortality rates are extremely high in early life. - Ex: fish, many invertebrates, and plants.

Age Structure of 3 Human Populations Using Age Diagrams

- Nigeria (Diagram A) has a growing population. The pre-reproductives are the largest group (shaped like a curved in triangle). - Australia (Diagram B) has a stable population because all groups are about the same size. (Shaped like a triangle). - Bulgaria (Diagram C) has a dying out population because the pre-reproductive class is getting smaller. (Shaped like a dome with a wide top half and skinny bottom half).

Sex Ratio

- Normally, in younger ratios: males/females > 1. This shifts to < 1 in older groups. - Females generally live longer than males in mammals. - In birds, males tend to outnumber females due to predation on females sitting on nests.

Large Scale Distribution

- Occurs over an area where there is considerable environmental variability. - Moss distribution and 8 different spatial scales

Physical Environment

- One of the two environments that make up an abiotic environment. The physical environment includes things such as temperature, light, geology, and topography.

Chemical Environment

- One of the two environments that make up and abiotic environment. The chemical environment includes things such as Oxygen, CO2, and Nutrients (P,N, S).

Mortality Curve

- Plot mortality rate (q(x)) on y-axis and age on x-axis.

Modern Ecology can be divided into three major fields:

- Population Ecology - Community Ecology - Ecosystems Ecology

Non-linear Curve of Population Growth

- Population growth is a function of the change in number over time and plotting the data gives a non-linear curve. - (Looks like an exponential growth curve).

Population Age Structure

- Populations can be divided into 3 classes with regard to age structure: pre-reproductives, reproductives, and post-reproductives. - There are 4 stages in Population Age Structure: Expanding 1, Expanding 2, Stationary, and Contracting

Type I Survivorship Curve

- Populations in which individuals have long life spans, survival rate is high throughout the life span with heavy mortality at the end. - Ex: humans, other mammals, some plants.

Rate of Population Change

- Rate of change is best described by the derivative of the equation: dN/dt = (b-d)/N. Exponential Population Growth: dN/dt = rN - This predicts the rate of population change through time. dN = change in # of individuals dt = change in time r = constant representing births minus deaths (growth) N = initial # in population

Examples of Exponential Growth

- Reindeer: 4 male and 22 female reindeer introduced to St. Paul Island, AK in 1910. In 30 years, it reached 2,000 reindeer. This shows the power of exponential growth. Eventually, the reindeer population crashed. - Whooping crane on brink of extinction in 1941-- U.S. fish and wildlife protected birds from hunting and preserved habitat and the population is recovering, although very slowly--still threatened.

Fecundity

- Reproductive output - Variables associated with fecundity: b(x), l(x), Σ, l(x)b(x) or R(0)

Type II Survivorship Curve

- Survival rates do not vary with age - Ex: adult birds, rodents, reptiles, and perennial plants.

Population Growth

- The change in number of individuals in a population with time. - Individuals are added via birth and immigration. - Individuals are removed via death and emigration. - Immigration and emigration occur in open populations, but not in closed populations.

Σ

- The gross reproductive rate = the average number of female offspring born to a female over her lifetime

l(x)b(x) or R(0)

- The net reproductive rate = the average number of females that will be produced during a lifetime by a newborn female - L(x)b(x) = R(0) - l(x) times b(x)-- because b(x) increases with age, but l(x) declines with age-- account for mortality = mean number of females born in each age group will be adjusted for survivorship.

Age-Specific Birth Rate (b(x))

- The number of births per female at age x. - Better way to express birth rate. - b(x) = the mean number of females born to a female in each age group. - Gross Reproductive Rate (Σ)

Crude Birth Rate

- The number of births per number individuals in the population per unit time. - Expressed as births per 1,000 population per unit time. - Only females give birth. - Birthrate of females generally varies with age.

Migration

- Two-way movement out and back in. Regular annual movements from feeding grounds to breeding grounds and back again. Ex: songbirds, waterfowl, and herd animals. - One way migration examples include salmon and eels (anadromous and catadromous)

Direct Control of Climate over Geographic Distribution

- Under direct control, the climate may be too hot, too cold, or too dry. - Ex: Kangaroos of different species (populations) are found in different parts of Australia but none are found in the northern part of the country. This is because it is too hot for one species, too wet for another, too hot in summer and too dry in winter for a third.

Time Specific Life Table

- Used for critters that live only one season--like insects. - Assume you sample each age class in proportion to its numbers in the population. - Assume age specific mortality rates are constant over the period of study.

Mark-Recapture Technique

- Used for measuring the density of large-animal populations 1) Capture animals (mostly vertebrates), mark them in some way and turn them loose 2) Wait for a while to let marked individuals mix with unmarked 3) Resample and assume that the ratio of marked individuals to unmarked individuals is consistent with the entire population.

Lincoln or Petersen Index

- Used to estimate the population size. Pop Size = (n1*n2)/(n3) n1 = total caught & marked the 1st time n2 = total caught the 2nd time n3 = marked animals caught the 2nd time

Transect Sampling

- Used to measure the density of plant populations. 1) Lay out the quadrants 2) Count the individuals per quadrant 3) Line transects: lay out several to many lines through the site and count all individuals encountered

Hula Hoop Sampling

- Used to measure the density of plant populations. 1) Lay out the quadrants 2) Count the individuals per quadrant 3) Throw out hula hoop in various directions and count numbers of individuals encompassed by each hoop.

How to interpret r (growth)

- When r > 0, births greater than deaths and the population grows. - When r = 0, births equal deaths and the population remains stable. - When r < 0, deaths are greater than births and population shrinks. - The rate of population growth (r) increases with increasing population size (Nt).

Geographic Distribution

- Where a population is found in the world. - It may be under the control of climate either directly or indirectly

Plant Dispersal Mechanisms

- Wind (ex: dandelion fuzz) - Transportation via animals (Ex: burrs sticking to clothing (externally), fruit going through digestive system so seeds go to soil (internally)). - Water

T(x)

T(x) = the total years lived into the future by individuals of age class, x, in the population. - How to calculate: add all of the L(x) so far. So for example if x = 0, you add L(0), L(1), L(2), L(3), L(4), and L(5). If x = 3, you add L(3), L(4), L(5).

Partial Pressure

Each gas exerts a part of the total pressure or partial pressure.

Ecology is a Scientific Research Discipline in which Questions are Posed about Nature (Ecosystem)

Ecosystem: flow of energy and nutrients through the physical and biological systems.

Life Expectancy (e)

Life expectancy (e) = the average number of years an individuals is expected to live from birth. - Using the life table for the gray squirrel e(x) = age-specific life expectancy = average number of years an invdividual of a given age (n(x)) is expected to live. - Several initial calculations are needed to determine e(x).

Dynamic Composite Life Table

Life table of individuals born in different consecutive years.

Clumped Distribution

Members are attracted to some feature of the habitat and live in clumps--resources unevenly distributed in habitat.

Uniform Distribution

Members are uniformly spaced--resources either randomly or regularly distributed

Random Distribution

Members of the population have an equal chance of being anywhere within the habitat--the resources are spread pretty evenly within the habitat.

Animal Dispersal Mechanisms

Most animals walk or fly to disperse, but some are dispersed by wind, other animals, or water.

Local Populations

Most populations are divided into local or subpopulations occupying habitats that are suitable and separated by unsuitable patches of habitat

Immigration

Movement into an area. The individuals move into a local population perhaps for food or mates.

Emigration

Movement out of an area. Individuals move out of a local population perhaps because it is too crowded, to look for food, to look for mates, etc.

Exponential Growth Model Equation (in order to get population size)

Nt = (N0)(e^rt) Nt = final population N0 = initial population members e^rt = exponent of growth

Abundance

Number of individuals in a population (typically a local population)

Question

Observations give rise to questions that seek an explanation of the observed phenomenon.

Net Reproductive Rate

R(0) = net reproductive rate = the average # of females that will be produced during a lifetime by a newborn female. ~ R(0) = 1; on average, females will replace themselves in the population. ~ R(0) < 1; females are not replacing themselves in the population ~ R(0) > ; females are more than replacing themselves in the population

Biosphere

Regions of the surface and sub-surface of Earth where organisms live.

b(x)

The mean number of females born to a female in each age group. - Age-specific birth rate

Density

The number per unit area or volume. - Lay out abundance in distribution on a grid, cells have differernt numbers of individuals (0-7).

Crude Density

The number/unit area over the distribution

Atmospheric Pressure

The sum of pressure exerted by all the gases in the atmosphere. Expressed in terms of mm of Hg or lbs/sq. inch.

Dew Point Temperature

The temp at which water vapor in a specific volume of air reaches Saturation Vapor Pressure. If air is saturated and the temp drops, the water in the air may exceed saturation and will condense (precipitate) as rain, snow, sleet, etc. depending on temp.

What drives weather?

The uneven heating of the Earth by the Sun drives the weather. - This results in air temperature differences around the world. - The differences drive the development of winds which redistribute heat. - This results in the development of high and low pressure cells. - Vertical and horizontal heat transport lead to the development of clouds (vertical) and the movement of tropical heat towards the poles.

Evaporation

Transformation of liquid water to vapor (requires 2260 joules/g liquid water--1 joule= .24 cal)

3 Idealized Types of Survivorship Curves

Type I, Type II, and Type III. - Some species show different curves at different times in life history.

Saturation Vapor Pressure

Water vapor content of the air at saturation. SVP is sensitive to temperature: it increases as the temp increases-- in other words, warm air holds more moisture than cold air.

Weather

Weather is the combination of temperature, humidity, precipitation, wind, cloudiness, and other atmospheric conditions occurring at a specific place and time.

Saturation

When evaporation = condensation, i.e., there is an equilibrium and the air is holding all of the water it can hold at a specific temperature.

Approximating the Age of Trees

You can approximate the age of trees by coring them and counting the rings. (The inner rings are the oldest, and the outer rings are the youngest.)

Modular Organisms

Zygotes develop into individuals that may then reproduce asexually to produce clones (common in plants and microbes, and some invertebrates).

Unitary Organisms

Zygotes grow into genetically unique organisms (most animals).

Measurable Statistics of Populations Include:

a) Density b) Distribution c) Age Structure d) Spacing of Individuals e) Births, deaths, and movement of individuals

e(x)

e(x) = age-specific life expectancy = the average number of years that an individual of a given age (n(x)) is expected to live. - How to calculate: Take (n(x))/(T(x)) for that row. For example, to find e(0), take (T(0))/(n(0)).

Survivorship Curve

l(x) on a log10 scale is on the y axis, with age on the x-axis.

Example of Lincoln or Petersen Index: After random sampling, 200 penguins are captured, tagged, and released. A month later, 180 untagged and 20 tagged penguins are captured. Use the Lincoln Index to estimate the total penguin population.

n1 = 200 n2 = 180 + 20 = 200 n3 = 20 Pop size = (n1*n2)/(n3) = (200*200)/(20) = 2,000 There are an estimated 2,000 penguins in this population.

l(x)

the probability at birth of surviving to any given age (x)

Life Table Columns and Variables

x = Age Class n(x) = # of individuals at each age l(x) = probability at birth of surviving to a specific age. l(x) = # alive n(x)/n(x) Ex: n(x0)/n(x0) then n(x1)/n(x0) d(x) = age specific mortality; d(x) = n(x0) - n(x1) q(x) = age specific mortality rate; q(x) = [d(x)]/[n(x)] for each age (x)

Population Growth Projection Variables

x = Age class n(x) = # of individuals of each age b(x) = mean # of females born to a female in each age group d(x) = age specific mortality q(x) = age specific mortality rate s(x) = age specific survival = 1 - q(x) l(x) = probability of surviving to a given age.

Gross Reproductive Rate (Σ)

Σ = the average number of female offspring born to a female over her lifetime.

Abiotic Environment

Comprised of the Physical Environment and Chemical Environment

Condensation

Conversion of water vapor to liquid water (releases equivalent amount of energy).

Scientific Method

1) Observations 2) Questions 3) Hypothesis 4) Predictions 5) Hypothesis Testing

Funding Sources for Ecological Research

1) Principle source is National Science Foundation 2) Most research projects are funded for 3 years with an option for annual renewal as long as long as things go well. 3) However, there is always significant and unpredictable variation in natural systems (ex: drought, wet years, fires, storms, etc that leads to considerable uncertainty) 4) Long-term research is funded by a special directorate in NSF the Long Term Ecological Research Program. 5) LTER funds projects in 6 year cycles--Original sites started in 1980 and most are still active.

Why study natural populations?

1) Understanding populations help with predicting the growth of human population 2) Helps with understanding how diseases and pandemics are spread 3) Help in controlling pests 4) Help in managing ecosystems to preserve and enhance Ecosystems Services (e.g., managing fish stocks for food, game fish & animals for sport) 5) Helps protect rare and endangered species and other natural resources.

The 8 Spatial Scales of Geographic Distribution

1) Worldwide 2) Continental 3) Region 4) Physiographic area 5) Cluster 6) Locality 7) Colony 8) Clump

Cohort

A group of individuals born at the same time (hour, day, month, or year). - Ex: a gray squirrel population in West Virginia that Bob Smith followed from birth until they all died about 6 years later.

Population

A group of individuals of the same species that inhabit a given area. - There is potential for reproduction among members of the population. - Populations have an identifiable distribution and spatial boundary.

Population

A group of individuals of the same species that occupy an area

Species

A group of organisms reproductively isolated from other similar and dissimilar groups.

Ecosystem

A natural unit with biotic and abiotic components that interact in a complex series of interdependent pathways to move energy and cycle nutrients. Could also be a forest, grassland, desert, or lake.

Observations

All scientific studies begin with observations of natural phenomenon

Metapopulations

All the local populations collectively

Vapor Pressure

Amount of pressure water vapor exerts in air

L(x)

L(x) = the average number of individuals alive during the age interval x to x + 1. - How to calculate: take each frame of n(x), add the two numbers, then divide by 2 to find the average. For example, for L(0), add [n(0) + n(1)]/2. Then for L(1), add[n(1) + n(2)]/2.

Hypothesis

An answer to the question is proposed that takes the form of a statement of cause and effect.

Community

An assemblage of populations in a defined area including microbes, plants, and animals. Examples include a forest, a grassland, and a desert.

Landscapes (Large Scale Natural Units)

Areas of land or water composed of mosaics of communities connected by organism dispersal and exchange of materials.

How old is Ecology?

As a formal science, Ecology is about 100 years old, but early humans learned to adapt and interact with their biotic and abiotic environment.

Ecology is a Scientific Research Discipline in which Questions are Posed about Nature (Biome)

Biome: patterns of biological diversity with geography

Ecology is a Scientific Research Discipline in which Questions are Posed about Nature (Biosphere)

Biosphere: interactions between ecosystems and the atmosphere, hydrosphere, and lithosphere.

Climate

Climate is the long-term average pattern of weather. It can occur at the local, regional, and global levels.

Ecology is a Scientific Research Discipline in which Questions are Posed about Nature (Community)

Community: factors that influence the relative abundance of species, how and community composition changes through time.

ENSO: El Nino-Souther Oscillation

Every about 5-7 years, the eastern pacific surface waters become warmer than normal due to a reduction in easterly trade winds reducing the normal flow of the Pacific to the west of NA. warmer water results in the moist ocean air rising and moving on shore where it rises and then precipitates on the west coast and further inland so NA experiences several wet years. This is called the El Nino. Periods between El Nino (la Nina) the reverse happens and NA is dry while the western pacific countries tries suffer floods. Look at the last 50 years and the el Nino seems to be more frequent.

Humans Role in Dispersal

Humans often aid in dispersal especially for pest species (gypsy moth, hemlock wooly adelgid, zebra mussel, chestnut blight, kudzu, etc.)

Ecology is a Scientific Research Discipline in which Questions are Posed about Nature (Landscape)

Landscape: factors that influence the spatial distribution of ecosystems and the effect on organisms.

Biomes

Large geographic regions with similar geologic or prevailing climatic conditions.

Latent Heat Energy (Evaporation)

Latent heat evaporation stored or released when water changes form (e.g., liquid to vapor) (540 cal/g)

Ecology is a Scientific Research Discipline in which Questions are Posed about Nature (Individual)

Individual: birth and death events

Dispersal

Individuals move around and away from each other at some point.

Actuary Table

It is the same as a life table, but it is used by insurance companies to see how much they should charge you for life insurance based on how long you might live.

Latent Heat Energy (Fusion of Water)

Latent heat of fusion of water stored or released when water changes from ice to liquid or liquid to water (80 cal/g)

Ecology is a Scientific Research Discipline in which Questions are Posed about Nature (Population)

Population: rates of birth and death, distribution of and density of individuals, immigration and emigration.

Predictions

Predictions that follow from the hypothesis must be identified. These predictions must be testable. - If the experiment results agree with the predictions, further observations will be made and further hypotheses and predictions will be developed to expand the scope of the problem being addressed.

Relative Humidity

The amount of water in a given volume of air as a percentage of the theoretical absolute humidity at that temp. Or, the amount of water vapor in the air expressed as a percentage of SVP.

Absolute Humidity

The amount of water in a given volume of air at a specific temperature.

Ecological Density

The density of critters in space that is actually habitable by the critter.

Hypothesis Testing

The predictions that follow from the hypothesis must be tested through observations and experiments (field and laboratory). Data from these experiments must then be analyzed and interpreted to determine if they support or reject the hypothesis. - If the experiment results are not consistent with the predictions, then the conceptual model of how the system works must be reconsidered and a new hypothesis must be constructed.

l(x)

The probability of surviving to a given age. - Survivorship column from life table.