BIOL 151 Exam 4 SDSU

What are the three key features of a population?

Size

Range

Density

Population size is affected by?

Birth Rate

Death Rate

Immigration

Emigration

Exponential Growth

The pattern of population increase that results when r (the per capita growth rate) is constant over time

Carrying Capacity

The maximum number of individuals a habitat can sustain without degrading the environment

Logistic Growth

The pattern of population growth that results as growth potential slows down as the population size approaches carrying capacity

What factors influence population growth?

Density-Dependent Factors

Density-Independent Factors

Density-Dependent Factors

Factors that affect populations that are influenced by the number of individual organisms, such as the use of resources or susceptibility to predation or parasitism

Density-Independent Factors

Factors that affect populations that are influenced by environmental factors such as droughts or severe storms

Intensive Census

Expensive but you get a close to exact population count

Flying around in a helicopter counting elephants

Extensive Census

Not as expensive but you don't get an exact population count

Done by sampling or estimation

Used for animals that are hard to see visually - ants or underground animals

What are the Population Descriptors? Define them.

Density - number of individuals in a specific area

Dispersal - How they are arranged in the area

Demography - age ratio, sex ratio, birth/death rates

Dynamics - change in population number over time

Clumping Dispersion

Packs or Herds

Water in the Dessert

Oaktree dropping saplings straight down

Uniform Dispersion

The pattern in which individuals are equally spaced throughout a habitat.

Bear territories

Corn field

Random Dispersion

Very rare in nature

Can't predict where an organism will end up next

Dandelion seeds

Population Size Formula

(CBR + Immigration) - (CDR + Emigration)

Lambda = (1 + birth rate - death rate)

Age Structure

The number of individuals within each age group of a population

Cohort

A group in individuals born at a given time

Demography

The study of the size, structure, and distribution of populations over time, including changes in response to birth, aging, migration, and death

R-Strategists

A species that produces large number of offspring but provides few resources for their support

K-Strategists

A species that produces relatively few offspring but invests considerable resources into its support

Life History

The typical pattern of resource investments in each stage of a given species' lifetime

Metapopulation

A large population made up of smaller populations linked by migration

Predation

Predators consume all of or part of prey

One organisms benefits, the other is negatively affected

Competiton

Individuals and species compete if their resource requirements overlap and that resource is limiting

Both organisms are negatively affected

Commensalism

An association between two organisms in which one benefits and the other is neither benefits nor harmed

Cockleburs and a dog

Mutualism

Both species benefit from their interaction with each other

Birds in the crocodile mouth

Plants and pollinators

Ants and trees

Fundamental Niche

The full potential range of the physical, chemical, and biological factors a species can use if there is no competition from other species.

Realized Niche

The range of abiotic and biotic conditions under which a species actually lives

Resource Partitioning

When species divide a niche to avoid competition for resources

Competition Exclusion

Proposition that two species competing for the same limiting resource cannot coexist at constant population values

Principles of Matter and Energy:

Matter Cycles (Goes to new Form), Energy Flows

Matter at the biological level is roughly constant

How do plants create mass?

Photosynthesis

(Sunlight and CO2)

What is the opposite of Photynthesis?

Cellular Respiration

Carbon Fixation

Chemically transforming carbon from a form that can not be used and fix it into a form that can be used

Primary Production

Total Amount of Carbon FIXED By Photosynthesis

Measured in (Grams of Carbon/Area/Time)

Expressed as Biomass

What is the Net Primary Production?

Energy left over after growth and biological processes happen

(Photosynthesis - Respiration)

Assimilation

The process by which organisms incorporate nutrients abstained from the environment into more complex molecules

Ammonification

The return of biological nitrogen to the environment as ammonia during the breakdown of organic matter by decomposers

Nitrification

Ammonia to Nitrite to Nitrate

Denirification

NO3- converting to N2 and releasing N2 back into the environment

Nitrogen Fixation

Chemically transforming nitrogen from a form that can not be used and fix it into a form that can be used

Production Efficiency (All Organisms)

(IEARP)

Ingest

Egest (Expel Wastes)

Assimilate (Growth)

Respire (Cellular Respiration

Produce (Total Biomass)

Production Efficiency Equation

P = I - E - R

Dividing by ingested amount would give you a percent

What percent of energy is passed from one trophic level to the next?

10%

Typically, how many levels of a Trophic Level are seen in a natural environment?

4-6

What is the second most abundant element in organisms?

Carbon

How many Carbon Dioxide Groups are there? What are these groups?

2

Fossil Fuels / Industrial Processes

Forestry / Other Land Uses

How could you tell the difference between CO2 forms?

Isotopes

As you move farther from the equator, what do you get?

Greater seasonal variation and greater variation in CO2 levels

How do we know about CO2 levels in the past?

Ice Cores or Isotopes

Recently there has been a (greater/smaller) variation in temperature differences between the poles and equator? Because of this, the polar vortex has been getting (stronger/weaker).

Smaller

Weaker

What is currently the best way scientists have to assess gas concentration in the atmosphere from the past, before yearly data was collected?

A) Make models of current conditions and predict them backwards

B) Ice core samples

C) Other than guessing, there is no way

D) Sample water from the ocean

B) Ice core samples

When two species occupy the same niche and overlap in niche space (choose all correct):

A) one species will always die out or move out of the niche

B) one species parasitizes the other

C) they are in a predator-prey relationship

D) both species will become extinct

E) they are in competition

F) one or both species will alter its niche space, and the species can coexist

E) they are in competition

F) one or both species will alter its niche space, and the species can coexist

Why is nitrogen fixation important in agriculture? Select all that apply.

A) Terrestrial plant growth is usually limited by nitrogen

B) Nitrogen slows down plant growth, so it is important to limit it in agriculture

C) There is an abundance if nitrogen in agricultural systems

D) Nitrogen is toxic to plants, so great care must be taken not to introduce it at all

E) Most terrestrial plants cannot fix atmospheric nitrogen themselves

A) Terrestrial plant growth is usually limited by nitrogen

E) Most terrestrial plants cannot fix atmospheric nitrogen themselves

How do you calculate Lambda?

A) 1 + Deaths - Births

B) Births - Deaths

C) Current Population + Births - Deaths

D) 1 + Birth Rate - Death Rate

D) 1 + Birth Rate - Death Rate

A mussel population can be modeled by the equation Nt = 400 (0.9)^t

What can we infer about the population?

A) The population is growing

B) The starting population is 90 mussels

C) The population is shrinking

D) The ending population is 400 mussels

C) The population is shrinking

Crows Sit on the Backs of Cows as They Graze.

Cows Stir Up Insects As They Graze for the Crows to Eat, and The

Crows Eat the Insects Off of the Cows So The Cows Are Less Likely to

Get an Insect-Borne Disease. What Kind of Species Interaction Is This?

A) Predation

B) Mutualism

C) Commensalism

D) Competition

B) Mutualism

A Flamingo Eats 4000 Joules of Plant Material. 2000 J is Eliminated as

Feces, 1500 is Used for Cellular Respiration, and 200 Joules are Used

for Growth and Reproduction. What is the Production Efficiency of

the Flamingo?

A) 125%

B) 1.25%

C) 12.5%

D) 200 Joules

C) 12.5%

Which of the Following Populations Would NOT Have a

Clumped Distribution?

A) Desert Animals

B) Herds of Grazing Zebras

C) Wolves that Hunt in Packs

D) Wildflowers Dispersed by Unpredictable Wind Direction

D) Wildflowers Dispersed by Unpredictable Wind Direction

Suppose the Carrying Capacity (K) of the Zebra Habitat is 400 Zebras...

What Is the First Year That the Carrying Capacity Will Be Exceeded?

Nt = 68 * (1.25)^t

A) Year 2

B) Year 6

C) Year 8

D) Year 7

C) Year 8

Suppose a population of Dolphins can be modeled by the following equation: Nt = 2200e^1.06t

Their coral reef habitat has a carrying capacity of 4,000 dolphins. What happens to the r-value as the dolphin population approaches K?

A) The r value will decrease because the carrying capacity cannot be exceeded

B) The r value will remain unchanged regardless of carrying capacity

C) The r value will increase to exceed the carrying capacity

D) The r value will decrease regardless of carrying capacity

A) The r value will decrease because the carrying capacity cannot be exceeded

This population can be described using a Discrete Exponential Model.

What equation can be used to calculate the population size over time?

(Year: 1) (Start Pop: 800) (Births: 288) (Deaths: 200)

A) Nt = 800 (0.89)^t

B) Nt = 800e^1.11t

C) Nt = 800 (1.11)^t

D) Nt = 288 (1.06)^t

C) Nt = 800 (1.11)^t

In a given ecosystem, the primary producers receive 16,400 joules of energy. How much energy do the secondary consumers receive?

A) 1.64 Joules

B) 164 Joules

C) 1640 Joules

D) 16,400 Joules

B) 164 Joules

Which of the following is NOT a way to increase your pet dog's production efficiency?

A) Feed it more treats

B) Take it for more walks

C) Don't wake it up from its nap

D) Feed it higher quality food

B) Take it for more walks

Which of the following population distributions is incorrect

A) Tigers Sharks - Random Distribution

B) Zebra Herds - Clumped Distribution

C) Wolf Pack - Uniform Distribution

D) Wildflowers Dispersed by the Wind - Random Distribution

C) Wolf Pack - Uniform Distribution

A Starfish has a production efficiency of 350 Joules. Which of the following statements is true?

A) A starfish ingested 350 joules of food

B) The starfish has 350 joules of energy available for growth and reproduction

C) The starfish has 350 joules of energy that is not used

D) The starfish requites 350 joules to keep its cells alive

B) The starfish has 350 joules of energy available for growth and reproduction

A goblin shark ingests 5000 joules of energy by eating a school of clownfish.

If the shark respires 1000 joules of energy each day and has a production efficiency of 50%, how much energy is egested?

A) 2500 Joules

B) 1500 Joules

C) Between 4000 and 5000 Joules

D) No way to tell with the given information

B) 1500 Joules

A panda population can be modeled by the equation: Nt = 15,000 (0.98)^t

What can we infer about the population?

A) The population is growing

B) The starting population is 98 pandas

C) The population is shrinking

D) The ending population is 15,000 pandas

C) The population is shrinking

A cardinal eats 4000 joules of plant material. 2000 joules is eliminated as feces, 1500 is used for cellular respiration, and 200 joules are used for growth and reproduction. What is the production efficiency of the cardinal?

A) 125%

B) 1.25%

C) 12.5%

D) 200 Joules

C) 12.5%

A blue whale's production efficiency is 700 joules. If the whale ingests 2000 joules and requires 850 joules for energy for cellular respiration, how much of the remaining energy is egested as waste?

A) 700 Joules

B) 45 Joules

C) Can't tell with the provided information

D) 450 Joules

D) 450 Joules