Biology and Society Final Exam

Which species concept defines a species as organisms that share a set of unique physical characteristics not found on other groups of organisms?

Morphological species

Species

primary classification group with most closely related members

Genus

broader group; capitalized first part of the name

Species (in a name)

second part of the name

Subspecies

additional name applied to more specific groups

The Biological species concept

a group of individuals that can interbreed and produce fertile offspring

Species are reproductively isolated

they cannot produce fertile offspring with members of other species

Gene pool

sum total of the alleles found in all individuals of a species

Gene flow

transfer of genetic material (alleles) from one population to another

prefertilization

prevents fertilization from occurring

postfertilization

fertilization occurs but hybrid cannot reproduce

Hybrid

life offspring produced by mating between two different species; often sterile

mule

hybrid of horse and donkey

Speciation

the evolution of one or more species from an ancestral from

Three steps for a new species

Isolation of gene pools of populations of the species
Evolutionary changes in gene pools of populations
Evolution of reproductive isolation between populations

Migration

small population becomes isolated in location far from main population

Allopatric populations

isolated from each other by distance or a geologic barrier (allo= “different”)

Sympatric populations

separate gene pools despite living near each other (sym-= “together”)

Gradualism

slow accumulation of small changes over long period of time (assumed by darwin)

Punctuated equilibrium

sudden, dramatic changes followed by long periods of little change

Biological race

populations of one species that have diverged from each other as a result of isolation of gene pools

Biologists may use genealogical species concept

organisms able to interbreed, descended from a common ancestor, and representing independent evolutionary lineage

The morphological species concept

a group of individuals with some reliable physical characteristics distinguishing them from all other species

more practical definition for paleontologists

scientists who study fossils

Homo erectus

immediate predecessor of homo sapiens

Human race

not independent evolutionary groups

Covergent evolution

unrelated organisms resemble each other due to similar environmental factors

Genetic drift

change in allele frequency that occurs due to chance (it is random)

A volcano eruption kills most of a squirrel population, the surviving squirrels have a different gene pool from the original population. What type of genetic drift did this?

Bottleneck effect

Founder Effect

genetic differences resulting when a small sample of a larger group begins a new population

Bottleneck Effect

variant of effect; a small number survives after disaster wipes out most of the population

Sexual selection

when a trait influences the likelihood of mating

Assortative mating

preference to mate with someone like self

Communicable or transmissible diseases

transmitted from one individual to another

infectious agents

invade tissues and induce damage

Epidemic

disease affecting many people within a region

Pandemic

disease that is prevalent over a whole country or the world

Pathogens

disease-causing organisms

Which statement about viruses is incorrect?

Viruses are prokaryotes

Contagious pathogen

spreads from one organism to another

Bacteria

tiny single cell prokaryotes

Toxins

bacterial secretions that also cause symptoms

Antibiotics

medications to routinely treat bacterial infections

Viruses

packers of nucleic acid (DNA or RNA) surrounded by a protein coat (capsid)

Herd immunity

indirect way to provide protection to individuals who cannot be vaccinated (pregnant women, infants, immunocompromised)

Skin and Mucous membranes are important components of the nonspecific first part of defense.

true

the immune system

protects against infection

first line of defense

nonspecific external defense

skin

physical barrier, sheds, takes pathogens with it

Mucous membranes

secrete mucus, line respiratory, digestive, urinary and reproductive tracts

First line of defense examples

ekin, mucous membranes, digestive secretions, vomiting

Second line of defense

nonspecific internal defense

Phagocytes

white blood cells that engulf and digest all invaders indiscriminately

Macrphages

one type of phagocytic white cell

Second line of defense

nonspecific internal defense

inflamation

response to tissue injury

fever

body temp above 97-99 degrees fahrenheit

Inferferons

produces by virus infected cells

complement system

enhances ability to fight off invaders

Second line of defense examples

interferons, complement system, fever, inflammation, phagocytes, macrophages

Which body structure secretes antibodies?

B cells

Third line of defense:

specific defense, used if pathogen gets through nonspecific defenses, made of white blood cells

B and T cells display specificity:

they recognize specific antigens

B and T cells produce antigen receptors

proteins that fit perfectly to antigens

B cells

lymphocytes that make antibodies

antibodies

proteins that identify and neutralize pathogens

T cells

lymphocytes that directly attack invaders, respond to body cells gone awry, fungi, cancer

Anticipating infection

ability of lymphocytes response to specific antigen, begins before birth

Immune response

ability to respond to infection

Cell mediated immunity

involves T cells rather than antibodies. t cells rapidly divide, produces memory cells

Memory cells

help body responds quickly to pathogen in future

Antibody mediated immunity

secreted antibodies attack pathogens; provided by b cells,b cell copies itself, making a clonal population of identical memory cells, these memory cells fight infection by secreting antibodies

Inactivation of the infectious agent:

occurs when antibodies encounter a pathogen matching the variable region

Vaccination

take advantage of long term protection from antibody producing memory cells

Tuberculosis(TB)consumption

disease caused by bacteria mycobacterium tuberculosis
-2 billion people carry TB
-new infection rate 1 per second
-causes 2 million deaths per year,Symptoms: cough that produces blood, fever, fatigue, long relentless wasting, nodules in lungs,1940s, antibiotics revolutionized TB treatment, then in 1980s antibiotic resistant TB increased, now 500,000 cases every year of multidrug resistant TB

Many humans would have to die for humans to develop resistance to the bacteria that causes tuberculosis.

True

Tuberculosis fits darwin's observations

Organisms in populations vary, bacterial variants of M. tuberculosis that resist antibiotics exist
The variation among organisms can be passed onto offspring. The genes for antibiotic resistance are passed to other bacteria
More organisms are produced than survive. Antibiotics eliminate most of the bacteria in the infected individual
An organism's survival is not random, bacteria with an antibiotic resistance are more likely to survive and reproduce

How can we stop drug resistance?

Combination drug therapy (drug cocktail), different drugs kill variants that have resistance to different compounds, prevents survival of organisms with resistance

Ecology

study of the interactions among organisms, as well as between organisms and their environment

Population

all the individuals of a species in a given area

Population structure

characteristics of a population, distribution and abundance

Distribution

the spacing of individuals

Abundance

the density of individuals

Population size

estimated by population ecologists (and others)

Direct counting

individuals are counted or surveyed, e.g. U.S. census

Mark-recapture method

Estimated the size of more mobile or inconspicuous species
, mark and release all animals found, later catch another group in same area and estimate population using percent marked in second catch

Population dispersion

how organisms are distributed in space
-Clumped distribution
-Uniform distribution
-Random distribution

On a global scale, what type of population distribution do humans show?

clumped distribution

Clumped Distribution

-high densities in resource rich areas
-low densities elsewhere
- ex. plants that require certain soil conditions

Uniform Distribution

-spacing between individuals tends to be equal
-species with this pattern are often territorial
-ex. Nesting penguins

Random Distribution

-shown by nonsocial species with ability to tolerate wide range of conditions
-also occurs where resources are distributed evenly or randomly
-ex. Plants with windblown seeds

Exponential growth

growth that occurs in proportion to the current total
-has a j shaped curve
-occurs under ideal growth conditions
-density dependent

density dependent

growth is not limited by population density or resource availability

super exponential growth

faster than exponential growth)
ex. human population

Growth rate

birth rate-death rate

birth rate

the number of births as a percentage of the population birth rate = 17.7/1000= 0/01700=1.77%

Current growth rate

1%

Demographic transition

the period when a society’s population shifts from high birth and death rate to low birth and death rates, usually happens during industrialization

Pre industrial revolution

high births and death rates, after death rates decrease, birth rates decrease