Chapters 1, 7, 8, 9, 10 Flashcards
Ecology
The Scientific study of how organisms affect and are affected by other organisms and their environment.
What species is considered to be “biological indicators” of environmental problems?
Amphibians
Why are amphibians good indicators of environmental problems?
Their skin is easily permeable- pollutants can pass through
Their eggs have no protective shell
They are exposed to pollutants and UV in both wet and dry environments
Controlled experiment
Experimental groups are compared with a control group that LACKS the FACTOR BEING TESTED
Replication
Performing each treatment more than once
What does replication in an experiment do?
Reduces the possibility that results are due to a variable that was not measured or controlled in the study
What happens when people alter one aspect of the environment
It causes other changes that we do not intend or anticipate
Ecology (def. #2)
Ecology is the scientific study of interactions between organisms and their environment.
Ecology (def. #3)
Scientific endeavor, not environmental activism
Ecology (def. #4)
The study of interactions that drive the distribution and abundance of organisms
Environmental Science
the natural sciences with the social sciences and focuses on how people affect the environment and how to address environmental problems
What do ecological studies usually emphasize?
individuals
populations
communities
ecosystems
What do ecologists study?
Interactions across many levels of organization
Population
A group of individuals of a single species that live in a particular area and interact with one another
Community
an association of populations of different species in the same area
biotic
living
abiotic
physical components
Ecosystem
A community of organisms plus their physical environment
Landscapes
areas with substantial differences, typically including multiple ecosystems.
what is the world’s biosphere composed of?
All the world’s ecosystems
What is a biosphere?
all living organisms on earth, plus, the environments in which they live.
What do ecologists evaluate competeing hypotheses with?
observations, experiments, and models
What are the different methods ecologists use?
Observational studies in the field
Controlled experiments in the lab
Experiments in the field
Quantitative models
What are the two scales of studies?
spacial scales and temporal scalees
Organisms life history
Record of events relating to its growth, development, reproduction, and survival
Life history characteristics include
Age and size at sexual maturity
Amount and timing of reproduction
Survival and mortality rates
Life history strategy of a species
overall pattern in average timing and nature of life history events
Life history events is shaped by the way the organism divides its time and energy between
Growth
reproduction
survival
Although all organisms produce offspring, what two characteristics vary?
Number and size of offspring
Semelparous
species have a single reproductive event (can be many offspring - but all at once)
Iteroparous
species can produce multiple times
itero
to repeat
pario
to beget
r-selection
selection for high population growth rates; an advantage in newly disturbed habitats and uncrowded conditions.
R-selection (def.)
the intrinsic rate of increase of a population
K-selection
Selection for lower growth rates in populations that are at or near K; advantage in efficient reproduction is favored.
K-selection(def.)
Carrying capacity for a population
Conditions of r-selected organisms
short life spans
rapid development
early maturation
low parental investment
high reproduction rate
Conditions for k-selected organisms
Long-lived
develop slowly
late maturation
invest heavily in each offspring
low reproduction rates
Fitness
genetic contribution to future generations
Trade-offs
Organisms allocate limited energy or resources to one function at the expense of another
What are some investments considered trade-offs?
Energy
Resources
Time
Loss of other activities
Example of trade-off
Species without parental care, resources are invested into propagules
lack clutch size
Maximum number of offspring a parent can successfully raise to maturity
True or False: Dispersal will not reduce competition among close relatives but will allow colonization of new areas
False: Dispersal will reduce competition and allow colonization of new areas.
True or false: Dispersal can allow escape from areas with diseases or high predation
True
Dormancy
State of suspended growth and development in which an organism can survive unfavorable conditions.
Why are small seeds, spores, eggs, and embryos best suited for dormancy?
Less metabolic energy is needed to stay alive.
Sequential Hermaphroditism
Changes in sex during course of the life cycle
Behavioral Ecology
The study of the ecological and evolutionary basis of animal behavior
Proximate causes
How the behaviors occur
Ultimate causes
why the behaviors occur; evolutionary and historical reasons
What 4 key factors are necessary for natural selection to operate?
Variations among traits
heritable
reproductive
survival
True or false: Animals make behavioral choices that enhance their energy gain and reduce their risk of becoming prey.
True
What factors effect finding food?
How much energy
How difficult it is to get food
optimal foraging theory
Animals will maximize the amount of energy gained per unit of feeding time and minimize risk involved
What does foraging theory assume?
That natural selection acts on the foraging behavior of animals to maximize their energy gain
In the equation P=E/t what does P stand for?
Profitability of a food item
In the equation P=E/t, what does E stand for?
Energy
In the Eequation P=E/t, what does t stand for?
time an organism spends obtaining the food
True or False: an animals success in acquiring food increases with the effort it invests
True
Marginal value theorem
was developed to address the question of how must an animal decide whether to stay in a patch or not?
What other factors could affect the costs of foraging?
Predators
abiotic challenges
What do anti-predator behaviors include
Those that help detect prey
avoid being seen
prevent attack
or escape
Sexual Selection
Individuals with certain characteristics gain an advantage over others of the same sex solely with respect to mating success.
teerritories
areas that they defend against intruders
Handicap hypothesis
Male that can support a costly and unweildy ornament is likely to be a vigurious individual whose overall genetic quality is high
Sexy son hypothesis
The female receives indirect genetic benefits through her sons, who will themselves be attracted to females and produce grandchildren
Monogomy
a male with only one female. This pairing may last for one or more breeding seasons. In many cases, both parents care for the young
Polygyny
One male mates with multiple females in a breeding season. The male may gain access to these females directly or indirectly. Female provides most-to-all parental care
Polyandry
One female mates with multiple males in a breeding season. The female may defend these males directly or indirectly. the male will provide most-to-all parental care
Promiscuity
both males and females mate with multiple partners in a breeding season.
Distribution
Geographic areas where individuals f a speecies occur
Abundance
number of individuals in a given area
What are important factors in calculating distribution and abundance?
Harvesting and conservation
Dynamic
distribution and abundance can change over time and space
True or false: Populations are not dynamic entities that vary in size over time and space?
False: Populations are dynamic entities that vary in size over time and space.
population
group of individuals of the same species that live in a particular area and interact with another
What are the interactions within a population?
competition and sexual reproduction
What is abundance reported as?
Population size or density
Density
Number of individuals per unit area
single genetic individual
ganet
ramet
includes members of a ganet that are genetically identical and may even be competing with each other
what are the limitations of distributions and abundances?
habitat stability
historical factors
dispersal
Other factors that affect distribution and abundance
Disturbance
Historical factors
Dispersal
Disturbance
abiotic events that kill or damage some individuals, creating opportunities for other individuals to grow and reproduce
true or false: dispersal limitations can prevent species from reaching areas of suitable habitat
True
What does dispersal of individuals in a population depend on?
Location of essential resources
competition
dispersal
behavioral interactions
Dispersion
Spatial arrangement of individuals within a population
Regular dispersion
individuals are evenly spaced
Random dispersion
individuals scatter randomly
Clumped dispersion
individuals are grouped together
Absolute population size
actual abundance
Area based counts
individuals in a given area or volume are counted
most often used to estimate the abundance of immobile organisms
Mark-recapture studies
subset of individuals captures and marked or tagged and then released
Used for mobile organisms
ecological nichee
abiotic and biotic conditions that a species needs to grow, survive, and reproducee
Niche model
predicts a species distribution based on conditions at locations the species is known to occupy
What do life tables show?
How survival and reproductive rates vary with age, size, or life cycle stage
Life table
Summary of how survival and reproduction rates vary w age
Survival rate
chance that an individual of age x will survive to age x+1
Survivorship
proportion of individuals that survive from birth to age x
fecundity
average number of offspring a female will have at age x
cohort life table
follows the fate of a group of individuals all born at the same time
Static life table
Snapshot in time: survival and reproduction of individuals of different ages during a single time period
requires estimating the age of individuals
Survivorship curve
Plot of the number of individuals from a hypothetical cohort that will survive to reach different life stages
Survivorship curve I
most individuals survive to old age
Survivorship curve type II
Chance of survival remains constant
Survivorship curve III
High death rates for young, those who reach adult hood survive well
In what ways can survivorship curves vary
Among populations
between males and females
among cohorts that experience different environmental conditions
Age structure
Proportion of the population in different stage classes
Age structure diagram
Shows the distribution of age and sex in a population
What two steps need to be calculated in order to predict population size for the following year?
- Number of individuals that will survive to the next time period
- Bumber of offspring those survivors will reproduce in the next time period
Stable age distribution
A population with an age structure that does not change
geometric growth
When a population reproduces in synchrony at discrete time periods
lambda = ?
Growth rate
Geometric growth =
Discrete growth
Exponential growth =
Continuous growth (babies at any time of the year)
Which unit is used for geometric growth rate?
Lambda
Which unit is used for exponential growth rate?
r
Exponential growth
When an individual reproduces continuously and generatios can overlap and the population changes in size by a constant proportion at each instant time
What is the unit of exponential population growth rate?
r, r= (births-deaths)/ population size
when do populations stay the same?
When lambda =1 or r=0
In the equation dN/dt=rN, what does dN stand for?
difference in population size
In the equation dN/dt=rN, what does dt stand for?
difference in time
what does e stand for?
the base of growth shared by all continually growing proceesses
Density independent factors
Effectts of birth and death rates are independent of the number of individuals in the population
Density-dependent factors
birth death and dispersal rates change as the density of the population changes
Population regulation
Density dependent factors cause population to increase when density is low and decrease when density is high
Logistic growth
population increases rapidly, then stabilizes at the carrying capacity
Carrying capacity
Max population size that the environement can support
Carrying capacity is indicated by the letter
K
