Exam 3 Bio 102
What R0 indicates a population is stable?
1
Primary producers use this chemical energy in two ways:
1. Cellular respiration to produce ATP to fuel metabolic processes 2. Growth and reproduction
Two events that produce exponential growth in a population
1. Colonization of a new habitat 2. Recovery after a disaster
What are the 2 components of an ecosystem?
1. Community of interacting species present in a region 2. Abiotic components (light, water, atmosphere, soil)
3 ways niches change in response to competition
1. Complete niche overlap leads to competitive exclusion and extinction of one species 2. Weaker competition has a restricted niche; weaker competitors use non-overlapping resources 3. *Niche differentiation*
2 Defenses to consumption
1. Constitutive 2. Inducible
Two types of niches
1. Fundamental 2. Realized
In general, the efficiency of biomass transfer from one trophic level to the next is only about
10%
How do you find Ro or net reproductive rate?
Add up each value in last column of life table and this tells if population is increasing or decreasing or steady indicates whether a population is increasing or decreasing as long as immigration and emigration are insignificant
Which species interaction applies to barnacles and whales?
COMMENSALISM
What are the 4 types of species interactions?
Competition (-/-) Consumption (+/-) Commensalism (+/0) Mutualism (+/+)
Logistic growth
K = carrying capacity r = per individual growth rate N = population
Which species interaction applies to bees that harvest nectar and pollen from flowers?
MUTUALISM
Can a realized niche be larger than a fundamental niche?
NO. a realized niche is a part of a fundamental niche
When primary producers invest energy to build new tissues this is called?
NPP and amount of energy available to consumers
Which of the following statements correctly states the leading hypothesis of how and why NPP is changing in the oceans?
NPP in the ocean is decreasing because increased surface water temperatures results in fewer nutrients reaching surface waters
Changes in NPP in the OCEANS
NPP is decreasing cause of upwelling no longer a density gradient with warm water on tope and cold water below
How and why NPP is changing on land in the ocean?
NPP varies among biomes tropical wet and tropical dry forests represent about 30% of world's NPP but cover less area than the ocean humans negatively affect NPP of earth by logging, deforestation, pollution, etc *NPP increased in northern hemisphere due to increases in CO2 (gives plants more fuel for photosynthesis)* *NPP decreased in southern hemisphere due to increased drought*
What best explains hare and lynx population cycles?
Predation limits hare population growth, but food availability is also important. The interaction of food availability and predation intensity
What is net primary productivity (NPP)?
Primary producer biomass or organic material that can be consumed
Ix means what..
Survivorship makes number of survivors a proportion out of 1
Fundamental niche
TOTAL theoretical range of environmental conditions that a species can tolerate
True or false? One example of a coevolutionary arms race is when faster deer evolve and favor wolves and cougars that have stronger eyesight and senses of smell.
TRUE A coevolutionary arms race involves two species that influence each other's evolution; faster deer favor predators with stronger eyesight and senses of smell to track them.
Which habitats are the most productive?
The tropical rain forests and coral reefs
Which of the following is a consequence of biomagnification?
Toxic chemicals in the environment pose greater risk to top-level predators than to primary consumers.
Most of the net primary productivity that is consumed is used for growth by primary consumers.
True; most NPP is used for growth by primary consumers.
In which survivorship curve do most of the organisms survive to maximum life span?
Type 1
3 types of survivorship curves are
Type 1 - humans Type II - songbirds Type III - insects/ turtles
Which survivorship curve has extremely high death rates for larvae or seedlings?
Type III
What makes species in early successional communities successful?
able to disperse their seeds over long distances
Ix multiplied by Mx = ?
average births per year per female
Which of these statements is true regarding biomagnification?
bioaccumulation is a concern for secondary and tertiary consumers
Two processes that increase population size
births and immigration
Four processes that affect population size
births, immigration, deaths, emigration
COMPETITION
both species are "hurt" energetically costly -- use energy to compete for resources, food, shelter 2 types: 1. intraspecific - within a species 2. interspecific- between species
MUTUALISM (+/+)
both species benefit Ie. When insects pollinate flowers and harvest nectar
Which of the following is NOT a density dependent factor?
catastrophic event
Random spacing patterns in plants such as the creosote bush are most often associated with ________.
chance
Population growth rate
change in number of individuals in population per unit time (deltaN/delta t)
Niche differentiation
change in resource use that occurs when species compete for many generations evolutionary population change
Character displacement
change in traits that enables partitioning to occur a species have competed for so long that they adapt and evolution occurs (long period of time with a change in allele frequencies) 2 species already exist evolutionary change that occurs in species traits that enables species to exploit different resources
What is the evolutionary change that makes niche differentiation possible?
character displacement
Which marine ecosystems have greatest NPP?
coastlines
Some birds follow moving swarms of army ants in the tropics. As the ants march along the forest floor hunting insects and small vertebrates, birds follow and pick off any insects or small vertebrates that fly or jump out of the way of the ants. This situation is an example of what kind of species interaction between the birds and the ants?
commensalism
Which process is not an example of consumption?
commensalism Examples of consumption are predation, herbivory, parasitism
Which of the four species interactions occurs when individuals use the same resources resulting in lower fitness for both (-/-)?
competition
Which species interaction depends on prey density and effectiveness of prey defenses to determine the impact on the prey population?
consumption (defenses include constitutive and inducible)
Two processes that decrease population size
deaths and emigration
What is the leading hypothesis for why NPP in the ocean is decreasing?
decreased upwelling
What is the study of factors that determine the size and structure of populations through time?
demography
Logistic growth is...
density dependent
Which of the following alters b and d rates irrespective of the # of indv. in the population?
density independent factor
Exponential growth is....
density-independent
Per capita rate of increase = r
difference between birthrate and death rate per individual b - d
Secondary succession
disturbance removes some or all of the organisms but leaves the soil intact EX: logging and fires
Primary succession
disturbance removes the soil and organisms EX: glaciers and volcanic eruptions
If two species are close competitors, and one species is experimentally removed from the community, the remaining species would be expected to _____.
expand its realized niche
What combines the abiotic and biotic components of an ecosystem?
flow of energy and cycling of nutrients needed to sustain life
5 types of Ecological study
global community population ecosystem organismal
What makes species in late successional communities successful?
good competitors for resources
Density independent factor
grows without reference or respect to population -- going to change the population regardless of what it is *Abiotic* *Random* affects birth and death rates EXAMPLES: *storms/weather changes*
CONSUMPTION (+/-) --> 3 types
herbivory parasitism (ecto/endo) predation
Natural selection involves energetic trade-offs between _____.
high survival rates of offspring and the cost of parental care
Type I survivorship (HUMANS)
high survivorship in beginning and extreme drop to low survivorship in old age
Population ecology
how and why does population size change over space and time
Community ecology
how do species interact and what are the consequences
Ecosystem ecology
how does energy flow and how do nutrients cycle through local environment
Density dependent factor
if growth is increased, it will eventually cease and level off at a carrying capacity *Biotic* *Nonrandom* define a particular habitat's carrying capacity EXAMPLE: *social behavior (ie. cannibalism), disease, parasitism, competition, predation*
Biomagnification (bioaccumulation)
increase in concentration of pollutants at higher levels in food chain
Inducible defense (consumption)
induced in the presence of a consumer PRO: saves energy CON: takes time to induce and may not be quick enough ie. mussels develop thicker shells in presence of crabs
Net primary productivity (NPP)
is energy invested in new tissue or offspring becomes available to organisms on higher levels of food chain
Generally, NPP is much higher on land than in the oceans. Why?
leading hypothesis is that there is much more light available on land than in the ocean
LATE successional species
long lived large good competitors
Type III survivorship (TURTLES/INSECTS/PLANTS)
low survivorship at a young age (high death rates as young) and high survivorship at old age/maturity
Carrying capacity
maximum number of individuals in a population that can be supported in a particular habitat over a sustained period of time *as a population approaches a habitat's carrying capacity, its growth rate should slow
Generally, NPP in oceans is greatest where?
near coastlines because of UPWELLING OF NUTRIENTS
What is represented with two bell-shaped curves moving apart from each other due to natural selection when niche is the horizontal axis label?
niche differentiation
Fecundity (Mx) means what...
number of female offspring produced by each female in the population
Nx means what...
number of survivors
Is NPP higher on land or in the sea?
on land because primary producers have more access to sunlight ocean water absorbs most of the usable wavelengths of light
COMMENSALISM
one species benefits and one species is unaffected difficult to quantify the absence of a cost EX: orchid and a tree/ whale and barnacles *RELATIONSHIP IS CONDITIONAL AND DYNAMIC. CAN CHANGE TO BE SOMETHING ELSE*
What is the overall change in NPP?
overall decrease
What type of relationship does mistletoe have with trees?
parasitic
Realized niche
part of fundamental niche niche a species ACTUALLY occupies
What action would increase the net primary productivity of an area of patchy temperate forest?
planting 500 new trees
Ro <1
population decreasing
R>1
population increasing
Ro = 0
population steady
In what populations does exponential growth tend to occur?
populations that colonize new habitats
Constitutive defense (consumption)
present even in the absence of consumers PRO: defense is always there CON: costs a lot of energy ie. grasshopper looks like leaf
What happens to energy as it passes through trophic levels?
productivity declines at higher trophic levels because energy is lost in consumption
Exponential growth and r
r itself does not change within a population
A population is growing exponentially and its instantaneous growth rate (r) is 0.02. Would the number of individuals added to the population (rN) be greatest at a population size (N) of 20, 500 or 1000?
rN would be greatest at the highest N (highest population)
*Logistic* growth of a population is represented by ΔN/Δt = ________.
rN x (K-N)/ K
NICHE
range of resources that a species is able to use or a range of conditions it can survive or live in
Succession
recovery of environment after a disturbance soil is number one factor in determining primary or secondary
*Exponential* growth of a population is represented by ΔN/ Δt = ________.
rmax N
EARLY Successional species
short lived small disperse seeds over long distances SLOW PROCESS
Type II survivorship (SONGBIRDS)
steady survivorship; same probability of dying at any age
Ecology
study of how organisms interact with their environment
What is a LIFE TABLE?
summarizes the probability that an individual will survive and reproduce in any given time interval over the course of its lifetime
The study of the Zootoca vivipara lizard showed that _____.
the low-elevation Netherlands population was intermediate for fecundity and survivorship when compared with other populations
Succession in an ecological context refers to...
the sequence of changes in species composition over time within the community after a disturbance
What is the fundamental niche of Chthamalus?
the upper and lower intertidal zones (area where they COULD exist)
Why does net primary productivity diminish with increasing trophic levels?
there is poor trophic transfer efficiency at higher trophic levels
Which of the following is true of species interactions?
they can act as agents of natural selection
Why don't populations normally grow exponentially?
they run out of resources
How does energy enter an ecosystem?
through primary producers receiving sunlight and using it for photosynthesis autotrophs transform solar energy into chemical energy through photosynthesis
Gross primary productivity
total amount of chemical energy produced in a given area and time period
Disruptive selection
two species are in the process of forming (graph of two bell-shaped curves moving away from each other is same as character displacement)
Which disturbance would result in primary succession?
volcano
Where on land is NPP greatest?
wet tropics by equator or in tropical areas sunlight is in greatest supply availability of sunlight and average temperature decrease with latitude
