exam 1 Flashcards
ecology
the study of organisms and their interaction between other organisms and the environment
Natural history
observes organisms and the environment (no testing just studying)
Environmental science
studies human impact on the environment
Conservation biology
aims to maintain habitats and diversity
resource management
attempts to balance human needs and the environment’s needs sustainably
population ecology
A group of individuals at the same place and same time. The study of the abundance, density, dispersion, and interactions of populations
community ecology
the study of the interactions of all the populations of all the species in the same area and time
organism ecology
studies organisms physiologically, behaviorally, and genetically and studies how organisms interact with each other and the environment
landscape ecology
the study of spatial patterns of ecological processes
global ecology
the study of how global-scale processes affect organisms
ecosystem ecology
studies the interaction of living and nonliving things in a specific place and time
evolution
change in populations over time
Hypothesis
A hypothesis is a tentative explanation; it proposes an
answer to the question being studied. Must be testable and repeatable
Independent variable
The independent variable is what is being
manipulated in the experiment.
Dependent variable
The dependent variable is what is being observed or measured in its response to the independent variable.
Controlled variable
A controlled variable is something that could
potentially affect the dependent variable but it is not what is being studied.
Experimental group
The experimental group is manipulated in the
study; it is subjected to the independent variable
Control group
The control group is not manipulated in the study
and it is not subjected to the independent variable. It is used for comparison to the experimental group with the assumption that the only difference between the groups is the independent variable
Alternative Hypotheses
the alternative hypothesis is one of the proposed propositions in the hypothesis test
The observed pattern of the data is not due to a chance occurrence
inductive reasoning
a body of observations is synthesized to come up with a general principle. from large generalizations to specific hypothesis testing
derive generalizations from a large number of specific observations
Deductive reasoning
general to specific, “if…then” hypothesis testing
null hypothesis
The alternative hypothesis that states the observed is due to chance alone. If the null hypothesis is falsified, then the observed phenomenon is not due to just chance.
working hypothesis
is the stepping stone to further ongoing research in hopes to formulate a tentative hypothesis
Batsian Mimicry
a harmless species looks like a dangerous one,
gaining protection because predators think it is
harmful, too.
what were the brown dummy snakes used as?
control group, to cancel out extraneous variables
that might affect predation rates
What were the artificial king snakes used as?
(hypothesis: one would likely predict that the king snake would not be frequently attacked in the area that overlaps with the coral snake, gaining protection from the resemblance.)
independent variable
what was the null hypothesis in the snake case study?
(hypothesis: one would likely predict that the king snake would not be frequently attacked in the area that overlaps with the coral snake, gaining protection from the resemblance.)
No difference in predation rates of king snakes in areas with and without coral snakes.
What was the working hypothesis in the snake case study?
(hypothesis: one would likely predict that the king snake would not be frequently attacked in the area that overlaps with the coral snake, gaining protection from the resemblance.)
Predation rates on king snakes would only be lower in regions where coral snakes were present.
what was the alternative hypothesis in the snake case study?
(hypothesis: one would likely predict that the king snake would not be frequently attacked in the area that overlaps with the coral snake, gaining protection from the resemblance.)
Predators simply avoid brightly colored animals and it has nothing to do with the lethality of the coral snake or mimicry.
what is the dependent variable in the snake case study?
number of attacks on each kind of snake
what is reductionism?
an approach to science that “reduces” down the bigger picture to more basic parts.
example would be studying organelles to understand the cell
What is Holism?
an approach in which all interactions of a system are considered. (the whole is greater than the sum of the parts.)
Suppose we want to study the role of wolf predation in controlling moose. what would be a reductionist approach?
only look at moose and wolves, keep all other factors constant (controlled) and then manipulate predation rates (maybe size of wolf population) to observe the effects on the moose population.
Suppose we want to study the role of wolf predation in controlling moose. what would be a holistic approach?
look at the entire food web (deer and rabbits compete with moose, these factors play a part in the abundance of moose)
what is proximate explanation?
It is the immediate cause of the phenomenon
example is more stored fat in birds yield a larger clutch size
What is ultimate explanation?
a more general explanation, often rooted in evolutionary principles.
what is a population?
A group of individuals of the same species inhabiting the same place at the same time.
give an example of a population
(example must check off these criteria) A GROUP of individuals of the same SPECIES inhabiting the same PLACE at the same TIME.
what parameters go into defining a population?
- landscape
- type of organism
- time frame
what is demography?
the quantitative description of a population (density, dispersion, sex ratio, age structure)
what is density and how is it expressed?
the number of organisms in one area
expressed as number of organisms per unit area, or unit volume
example: number of squirrels / km2
crude density
doesn’t take into account habitat and just counts the number of organisms
example: the number of squirrels in a park
ecological density
takes habitat into account and is the number of organisms per unit of appropriate habitat
example: number of squirrels in the grassy area of the park
what is a census/ direct count best used for?
large organisms that can be counted easily
what is area of coverage best used for?
spread out or hard to count organisms like mosses or mushrooms
Estimate of Absolute Abundance
Sometimes a direct count is not feasible- animals hide or are hard to see, or there may be too many of them to catch or count them all. Estimates are then made by sampling the population and calculating a population estimate
What are some of the difficulties with censusing?
animals can be too abundant, they can hide, and be too hard to see
What is an Index of Relative Abundance?
uses indirect evidence to gauge population size
example: fecal pellets (deer), burrows (field voles), bird calls or nests…
What is the Lincoln-Peterson method?
organisms that are more mobile are caught, marked, and released. this allows us to study population sizes
What assumptions must be met to be
confident in your estimate for the Lincoln-Peterson method? (4 points)
- marking does not affect mortality
- Marking does not affect the probability of recapture (animals are too attracted to trap or avoids trap)
- No changes in population size between t1 and t2
- Marked individuals mix in well with the population (often disturbed animals lay low)
What is dispersion?
spatial distribution of individuals in a population
What are the three patterns of dispersion, and what are some of the causes of each?
- uniform “even”: usually caused by social
interactions such as territoriality or chemical signals in plants (not a common pattern) - random: the presence of an individual does not provide any information about the likelihood of finding another nearby this pattern occurs when the habitat has a homogeneous distribution of resources for that particular organism and there is a lack of both attractive forces and repulsive forces between organisms.
- clumped or aggregated: once you have found
one organism, the likelihood of finding more nearby is increased. often caused by appropriate habitat and social interactions
what are the 4 categories of sex ratio?
- Primary Sex Ratio: sex ratio at fertilization
- Secondary Sex Ratio: sex ratio at birth
- Tertiary Sex Ratio: sex ratio at sexual maturity
- Quaternary Sex Ratio: sex ratio of adult population
What is age structure?
the number of individuals in a population in each age class
how can the age of some organisms be determined?
plumage in birds, color change or patterns, growth rings in fish scales or trees, teeth
What are the two types of life tables? How is the data collected for each?
- Static: sample of a population in a moment in time
2. Cohort: follows a single group from life to death
what is a survivorship curve
a way to visually show mortality trends
Total fertility rate
the total number of children a female is expected to bear in her lifetime
Replacement rate
If a female produces exactly 2 offspring she exactly replaces herself and her mate
What is a population pyramid
Population pyramids are a visual representation of Life Table data. In a pyramid, you see the population indicated by age class, separating males and females.
What is positive population growth?
if population increases in size
What is Negative population growth?
if population decreases in size
What affects population growth? (7 points)
- age structure (having a large proportion of the female population at or before reproductive age is going to bring about positive population growth)
- sex ratio (number of births in a population is usually related to the number of females)
- reproductive/ fertility rates
- generation time (the average length of time between the birth of an individual and the birth of its offspring)
- infant mortality and life span
- immigration and emigration
What is r “The Biotic Potential”
r = the natural rate of increase for a population in ideal conditions. (r = births - deaths)
What does dN/dt mean?
the current rate of change in a population size
the change in number of individuals in a population “N” over the change in time “T”
What is the difference between exponential and logistic growth?
- exponential growth will have a “J” shaped curve where logistic growth will have a “S” shaped curve
- exponential growth will continue to rise where logistic growth will stabilize as it reaches K (carrying capacity)
What is logistic growth? What conditions may it occur?
- Populations with logistic growth exhibit a decrease in the per capita rate of increase as the carrying capacity is reached
- incorporates the effect of resource limitations
- logistic growth will have a “S” shaped curve
Give a natural example of exponential growth
introducing a species to a new environment
- for example: algae colonizing a newly formed pond
- another example: an invasive species taking over an environment making it an unlimited competitor (spreading quickly)
Why can’t Exponential growth cannot be sustained indefinitely?
resources are not unlimited
What is “K”?
- the carrying capacity (maximum population size a habitat can support)
- not a fixed number and can vary as
environmental conditions change
How does the population stabilize?
limited resources, birth rate decreases, and death rate increases
What demographic factors are important in predicting population growth? (3 factors)
fertility rates, mortality rates (life expectancy), the initial age profile of the population
What is demographic transition?
Demographic transition is when high birth and death rates become low birth and low death rates, achieving zero population growth
What are the 3 types of fluctuations that can occur in the size of a population? (think of how they appear on a graph)
- irregular (no pattern)
- irruptions (low density at first then an unexpected spike) appear from perhaps good weather or an abundance of food
- cycles (most regular)
What are density-dependent factors? Give an example.
factors that change with population size (most often biotic)
examples are: food availability, predation, and disease
What is meant by “lag time”?
there is a “lag” or delay between the factor happening and the population rise
What are density-independent factors? Give an example.
Density independent factors are usually abiotic factors whos affect on birth and death rates do NOT change with changes in population density
Examples would be: temperature or natural disasters
describe the concept of equilibrium view, and what factor (density-dependent or density-independent) is associated with an equilibrium view?
density dependence factors lead populations to equilibrium
What is a metapopulation and how does it affect population density?
a group of subpopulations interconnected by dispersal. A collection of subpopulations is called a Metapopulation
Generally, metapopulations are found where habitats are patchy and of varying quality.
What is life history?
any aspect of the developmental pattern and mode of reproduction of an organism
What are the 4 aspects of life history?
- body size
- metamorphosis (Is there a major developmental change in the shape or form in the life?)
- dormancy (Is there a “resting stage” in the life cycle?)
- reproductive strategies (details and patterns in its reproductive life)
What effects can body size have on an organisms’ life history? (4 points)
- (resources/placement) what factors affect its life? larger trees get more sunlight and are more susceptible to lightning strikes
- (amount of food) energy consumption? larger animal consume more than smaller organisms
- (efficiency of metabolism) what organism in more efficient in its calories/gram? As animal size increases, surface area increases more
slowly than volume -> meaning smaller animals lose more heat and work more to stay warm - (how long it lives) life span? as animals get bigger pulse rates slow down and life spans are longer
What is Metamorphosis?
the transition between two or more distinct stages in an organism
Give an example of metamorphosis
tadpoles and adult frogs have entirely different requirements so every system in the body changes to accommodate these needs
What are 2 advantages of metamorphosis?
- larva and adults don’t have to compete with each other
- feeding, reproduction, and dispersal are optimally separated across stages (meaning that the different life stages are optimized for a specific need. an example would be adults are specialized for mating and larva are specialized for growing)
What is diapause?
a “resting stage” in which all growth and
development stops and metabolic rate drops. Rather than dying when conditions are not conducive to survival and/or reproduction, the organism goes into a state of dormancy waiting for conditions to improve.
What are some advantages of diapause?
- when environments become harsh and inhospitable, organisms can avoid those conditions by going into their resting stage
what are the advantages of asexual reproduction?
Because asexual reproduction does not change the genotype of the offspring, asexual reproduction is best in environments that are very stable and unchanging.
Also, there is no need to find a mate, which is good in a situation where there may not be another, such as a lone colonizer or parasite.
What are the advantages of sexual reproduction?
- genetic recombination and produces offspring genetically different from the parents.
- best in changing environments
What is energetics?
organisms have a finite amount of energy available to them for reproduction
What are some of the tradeoffs between large and small litter/clutch sizes?
large litters: higher cost of feeding a larger litter, increased conspicuousness to predators, lower weights
small litters: mortality success is lower
What is iteroparity?
Iteroparity organisms have multiple reproductive cycles over the course of its lifetime
What is Semelparity?
Semelparous organisms reproduce only once during their lifetime
what are r-selected species?
r- selected species, are commonly found at low population densities where growth is exponential. These are species regularly decimated by catastrophes.
What are k-selected species?
k-selected species have higher population
densities, near or at K. These K-selected species face intense intraspecific competition for scarce resources. these species must invest in their young to produce competitive offspring.
