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Biology 221 Notes Exam I. Powerpoint 1. Biolog y is the study of life. There are currently millions of extant (living) species (see below for taxonomic levels). Properties that are shared by all living organisms. Order.

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Biolog y is the study of life
Biology is the study of life

There are currently millions of extant (living) species (see below for taxonomic levels)



Order
Order

Each organism possesses a highly ordered structure even if they may seem simplistic (like prokaryotic cells or single-celled eukaryotic organisms).


Growth development and reproduction
Growth, development, and reproduction

All reproduce and pass their DNA from parent to offspring. DNA then directs the pattern of growth and development.


Response to stimuli sensitivity
Response to stimuli (sensitivity)

All organisms respond to internal and external stimuli.


Energy processing
Energy processing

All living organisms obtain and then transform energy into a usable form (ATP).


Homeostasis
Homeostasis

All organisms are capable of maintaining a relatively stable internal environment. This is accomplished by feedback mechanisms


Evolutionary adaptation
Evolutionary adaptation

Living organisms adapt to their environments.


Regulation
Regulation

Living organisms have regulatory mechanisms that function in the coordination of the organism’s functions.


Structural levels of biological organization
Structural levels of Biological Organization

is based on structural levels with each level building on the levels below it.

Note that with each step upward in the hierarchy that there are new properties that are not present at the previous level (emergent properties).

Emergent properties are due to the arrangement and interactions of parts as complexity increases


The Eight Unifying Themes of Biology

(Reece et al., 2011).

Please note that different textbooks may organize these a bit differently.


Emergent properties
Emergent Properties

are those that are unique to a higher level of organization (this is also consistent with some non-living objects).

1. Reductionism is the study of components of complex “systems”. It makes experimentation easier to look at individual parts instead of the whole system.

2. Systems biology models whole systems by focusing on the interactions of the parts.


Interactions
Interactions

between organisms and the physical environment

Elephant and other animals eat leaves and fruit of tree, leaves of tree convert sunlight energy to energy in glucose (photosynthesis), nutrients are cycled etc.


Energy and energy transfer
Energy and energy transfer

are necessary for all living organisms (also a property of living organisms).


Form fits function
Form fits function

Correlation of structure and function

The cheetah has long legs, large lung capacity and other structures allow it to attain great speed.


Cell

The cell is the basic unit of life and all cells have a membrane and DNA


DNA

(deoxyribonucleic acid) is passed from parent cells to daughter cells and from parents to their


Feedback mechanisms
Feedback mechanisms

that lead to regulation of cellular and multicellular activities


Evolution
Evolution

The core theme of biology is Evolution.

Theories are much broader in scope than hypotheses. Thus theories are comprehensive and are supported by an accumulation of extensive and varied evidence.


Taxonomic levels
Taxonomic levels

Throughout history humans have attempted to categorize the different species into different groups.


First there were two kingdoms of life
First there were two Kingdoms of Life

Linneaus suggested two kingdoms based on the ability of the organisms to move: Plants that did not move and Animals that did.

Ernst Haeckel suggested creating a third kingdom Protista


Then there were five kingdoms of life
Then there were Five Kingdoms of Life

More recently, biologists have attempted to categorize organisms according to the phylogenetic (actual, historic) relationships among them. In 1969, Whittaker proposed the five Kingdom system (Monera, Protista, Fungi, Plantae, and Animalia).


Now there are three domains
Now there are Three Domains

There are currently three domains (Bacteria, Archaea, and Eukarya) The Domain Eukarya is then divided into multiple kingdoms (four or more).


Kingdoms are subdivided into increasingly inclusive taxa. In general Kingdoms are divided into various Phlya (singular phylum), Phyla are divided into multiple Classes, Classes are divided into Orders, Orders are divided into Families and Families are divided Genera (singular Genus), and a genus is divided into multiple species.


All species have a two-part name (Linneaus) that consists of the genus and species. The first letter of the Genus name is always capitalized and the first letter of the species name is lower case. The name is italicized or underlined because it is derived from Latin

UrsasamericanusOR

Ursasamericanus


Science as a process
Science as a process

Scientific discoveries are basically made by using one of two methodologies.


Discovery science is also known as descriptive science
Discovery science is also known as descriptive science

Involves observing and documenting phenomena without experimentation. A recent example is the sequencing of the human genome. Conclusions are often based on inductive reasoning. Inductive reasoning uses specific observations to construct general scientific principles.


Hypo deductive science based on hypothesis testing and deductive reasoning
Hypo-deductive Science. Based on hypothesis testing and deductive reasoning.

Hypotheses are simply educated guesses. Null hypotheses are those that suggest that there are no differences between the control and the experimental groups whereas alternative hypotheses are those that suggest a difference.

Deductive reasoning is the opposite of inductive reasoning; from general premises, one extrapolates to the specific results that are expected if the premises are true. In general the predictions are the potential outcomes of the experiments that should be expected if a hypothesis is correct.


Ecology
ECOLOGY

the study of interactions between organisms and their environments


Ecology can be studied at various levels


Organismal ecology
Organismal ecology

includes various sub disciplines of biology (e.g., physiology) dealing with the organism and its natural history.


Population ecology
Population ecology

Population (a group consisting of individuals of the same species living in a given area) ecology deals with the factors that affect the population (specifically its size and changes over time)


Community ecology
Community Ecology

Community (the different populations of the different species living in a given area) ecology is related to the interactions of the different species that make up the community


Ecosystem ecology
Ecosystem Ecology

Ecosystem (the biotic and abiotic factors in a given area) ecology is the study of the living organisms and the biogeochemical cycles and energy flow that affect them.


Landscape ecology
Landscape Ecology

Landscape ecology involves the different types of patches (e.g., corridor of trees lining a river flowing through a sparsely vegetated plain) and research focuses on the factors controlling the exchanges of energy, materials, and organisms among the ecosystem patches.


Biosphere the habitable portion of the earth
Biosphere (the habitable portion of the Earth).

Global ecology is the study of the biosphere. Global studies are difficult in that there is no control. For example it is difficult to study the specific causes and their exact impacts on Global Climate Change. However, evidence does suggest and most scientists agree that the climate is currently changing and that human activities play a role in that change.


Abiotic factors and climate
Abiotic Factors and Climate

Abiotic factors and climate (the long term prevailing weather conditions of a given area).

Factors that impact climate (moisture and temperature in particular):


Sunlight intensity
Sunlight intensity

Sunlight intensity varies with latitude; the most direct sunlight occurs at the equator.


Season
Season

Season also affects the sunlight intensity (the planet changes position)


Air circulation
Air circulation

Air circulation affects precipitation












Aquatic biomes include
Aquatic Biomes include:

Lakes

Wetlands

Streams and Rivers

Estuaries

Intertidal Zones

Oceanic Pelagic

Coral Reefs

Marine Benthic Zones

Note that pollution is a big problem for most of these, that wetlands are often the sites of human development, and that overharvesting resources is decreasing the population sizes of many aquatic species.


Factors affecting the dispersal and distribution of organisms
Factors Affecting the Dispersal and Distribution of organisms

Dispersal is the movement of organisms away from areas of high population density or the area of origin. The ranges (areas where the species occurs) are expanded by dispersal. Some species disperse more easily than others.


Distributions
Distributions organisms

A few species have wide distributions (e.g., humans) but most of the species of living organisms occur in relatively limited geographic ranges. Biogeography is the study of the distributions of species.


How do living organisms end up where they do
How do living organisms end up where they do? organisms

Dispersal or inability to disperse to an area:


How do living organisms end up where they do1
How do living organisms end up where they do? organisms

Other factors include:

Behavior e.g., habitat selection

Biotic e.g., interspecific competition,

Abiotic e.g., temperature

Climate


Plethodon shenandoah and talus
Plethodon shenandoah organisms and talus


Plethodon cinereus and habitat
Plethodon cinereus organisms and habitat


How do living organisms end up where they do2
How do living organisms end up where they do? organisms

Unfortunately humans have facilitated some dispersions that have had negative even catastrophic effects


Population ecology1

POPULATION ECOLOGY organisms

the study of populations (groups of individuals of the same species living in a given area) and their relationships with their abiotic and biotic environments


Population size n is the number of individuals that make up the gene pool
Population size (N) is the number of individuals that make up the gene pool

Population density is the number of individuals that live in a defined area or volume

Changes in population density and number are affected by:

1. Birth rate and death rate

2. Immigration and Emigration


Exponential growth
Exponential Growth up the gene pool

Equation dN/dt = riN

where: d = the change in, N = the number of individuals in a population, t = time, and ri = rmax= the intrinsic rate of natural increase.

Species that experience periods of exponential growth are called r-selected species. They tend to:

1. Reproduce at a young age

2. Produce many small young

3. Offer little parental care


Logistic growth
Logistic growth up the gene pool

takes into account the factors that regulate population growth and the concept of a carrying capacity (K) or the population size at which stabilization occurs


Logistic population growth
Logistic Population Growth up the gene pool

Equation

dN/dt = riN(K-N/K),

where K = carrying capacity, see above for other variables

Species that show a stabilization of N are called K-selected. They tend to:

1. Reproduce later in life

2. Produce fewer, larger, and more developed offspring.

3. Provide a great deal of parental care


Population regulation up the gene pool


Density dependent factors
Density-dependent factors up the gene pool

Those related to the number of individuals present in the population.


Density independent factors
Density-independent factors up the gene pool

Have their effects regardless of N.


Demography
Demography up the gene pool

the study of factors that determine the size and structure of populations through time. It involves:


Age structure the number of individuals of each age and sex ratio proportions of males to females
Age structure up the gene pool(the number of individuals of each age) and Sex Ratio (proportions of males to females)

Age structure is important because fecundity (the number of offspring produced in a given time interval) and mortality rates vary for different age groups or classes.

Sex ratio is important in that the number of births is usually more closely related to the number of females rather than the number of males.


A life table
A life table up the gene pool

summarizes the probability that an individual will survive and reproduce in any given year over the course of its lifetime.


Survivorship curves
Survivorship Curves up the gene pool


Density and Dispersion (the pattern of spacing among individuals within the geographic boundaries of the population


Determination of density
Determination of Density individuals within the geographic boundaries of the population

1. determined exactly by counting but the organisms need to be sessile (e.g., plants, barnacles) but this method does not work so well for mobile animals

2. estimated by sampling multiple smaller plots, obtaining an average, and then extrapolating the data

3. The mark-recapture method is commonly used and involves the capturing individuals, then marking them and releasing them. Afterward a second sample is taken and the percent of marked individuals recaptured is recorded. To estimate the total population from these data, researchers make the assumption that the percent of marked and recaptured individuals is equal to the percent of marked individuals in the entire populations.

Mark-recapture equation

Equation m2/n2 = n1/N

where:

m2 = number of marked individuals in the second sample

n2 = marked + unmarked in second sample

n1 = number of individuals caught in the first sampling attempt

N = total population size (solve for N)


Patterns of dispersion
Patterns of dispersion individuals within the geographic boundaries of the population

clumped or with individuals aggregated in patches

uniform or evenly spaced

random or where the position of one individual is independent of other individuals).


Human population growth
Human Population Growth individuals within the geographic boundaries of the population


Demographics part i
Demographics Part I individuals within the geographic boundaries of the population

Growth rate formula: Growth Rate = (Crude birth rate - crude death rate). Crude birth rate is the number of births/1,000 people & crude death rate is the number of deaths/1,000 people. Depends on: age at which people get married, amount of education, career vs. stay at home women, contraceptive use, number of children desired by the couple, cultural values, and religious beliefs.

The doubling time or the time it takes for a population to double is calculated as follows: Doubling time = 70/Growth Rate (%). Developed countries in general have longer doubling times than developing and third world nations.


Demographics part ii
Demographics Part II individuals within the geographic boundaries of the population

Total Fertility Rate (TFR) is the number of children that women are expected to have in their lifetimes.

A country reaches zero population growth when birth rates = death rates and immigration = emigration.

After a country reaches replacement level fertility, population growth can still occur. In fact worldwide the population will still continue to grow even if all nations reach replacement level fertility.

The age structure of a population also affects population growth.



Expansion into new habitats

Expansion into new habitats but are not limited to:


Increased k
Increased K but are not limited to:

Although most living organisms cannot change their carrying capacities, humans have been able to increase theirs. There are many disagreements concerning the Earth’s carrying capacity for humans. Some people believe that we have already surpassed K, while others think that it may be as high as 1,000 billion.


Side stepping limiting factors
Side-stepping limiting factors but are not limited to:

Decreased infant mortality as a result of increased food supplies, the Agricultural Revolution, the Industrial Revolution, the technology, medicines, and sanitary living conditions.

Increased life spans


Social influences
Social influences but are not limited to:


Religious influences
Religious influences but are not limited to:


Is this a problem
Is this a problem? but are not limited to:

Some say yes

Others say no


But--- but are not limited to:

It makes since that the more people we have, the more impact on resources and the environment. However, the people of developed nations tend to have a larger-

The Ecological Footprint takes into account resources needed and wastes produced by humans. http://www.myfootprint.org/ .


Should or can human population be controlled
Should or can human population be controlled? but are not limited to:

Mandatory limits on number of children

Educational programs extolling the benefits of smaller families

Family planning

But all of these are controversial


Demographic transition
Demographic Transition but are not limited to:

Another possibility is raising the standard of living in third world countries through demographic transition


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