Studied by 6 peopleecology
the study of the interactions of living organisms with their environment
goal: to understand the distribution and abundance of living things in the physical environment
Ecology sublevels
organism
population
community
ecosystem
organism
in a forest, each tree is an organism
population
in a forest, all pine trees make up a population
community
all the species or populations within an area and the interactions between species
ecosystem
all the living (biotic) and nonliving (abiotic) things in an area at a given time
evolution
the change in heritable characteristics of a biological population over successive generations, ie. the process by which new species arise and biodiversity is generated
unit of evolution
population (individuals do not evolve)
natural selection
process that leads to evolutionary change
mechanism by which species with more favorable traits for a given environment are better able to survive and reproduce, thus changing the population
epistemology
the study of knowledge
empiricism
perception and sensory
evidence is gathered from our senses and experiences
science is based on this
process of empiricism
use sensory means
make observation
rationalize
draw conclusion
gain empirical knowledge
inductive reasoning
starts with a specific observation, then makes generalizations based on those (used to form hypothesis)
observation → pattern → hypothesis → theory
deductive reasoning
starts with a general premise, then predicts specific result based on that (used to test hypothesis)
theory → hypothesis → observation → support
for science to work, it must what?
be testable
be falsifiable
be reproducible
be verifiable
basic science
knowledge for the sake of knowledge, regardless of application
applied science
uses scientific knowledge to solve real-world problems, often relies on basic science
descriptive science
based on observations
hypothesis-based science
asks “why”
hypothesis
must be falsifiable
dependent variable
what is being tested or measured to see if it depends on the independent variable
independent variable
changed to test its effect on dependent variable
control group
exposed to baseline independent variable conditions
experimental group
exposed to variations in independent variable
controlled variables
parameters held constant between groups
correlation
statistical relationship of the relationship of two or more variables
causation
one variable is the source of a given affect on another variable
confirmation bias
tendency to search for, interpret, favor, and recall information in a way that confirms or supports one’s prior beliefs or values
sampling bias
occurs when research samples over or under represent certain groups
publishing bias
certain studies or results are more likely to be published
observer bias
systematic variation between true value and the value actually observed by the observer
(seeing what you expect or want to see)
biodiversity
the number of species and their relative abundance to each other in a given space
genetic diversity
variability in genetic material that provides adaptive potential
chemical diversity
diversity of metabolism, proteins/enzymes, byproducts produces by organisms
ecosystem diversity
number of different environments on the planet or in a geographical region
taxonomic biodiversity
number of species
taxonomy
classification and naming of organisms/species
biological species
group of organisms that can interbreed to produce fertile offspring
phylogenetic tree
classing them together based on what they look like
sister groups
next to each other on phylogenetic tree and are more closely related to each other than other groups
common ancestors
extinct organisms that groups evolved from in the evolutionary past and are represented on the nodes where branches split
prokaryotes
first organism
single-celled
anaerobic (no oxygen)
cyanobacteria
single-celled
evolved ability to produce oxygen and transformed earth’s atmosphere
eukaryote
true nucleus
organelles - organized by membranes
multicellularity
can grow larger
can specialize cell types
plants
fungi
animals
species richness
number of species in a location
relative abundance
how many of each type of species is present in relationship to other species
native species
occur in a certain ecosystem due to natural distribution and natural evolution
endemic species
native to a single geographical location, i.e. evolved in one location and never spread out
extinction
species entirely dies out
6th mass extinction
habitat loss and fragmentation
overharvesting
species introductions
exotic/ invasive species
pollution
climate change
invasive species
harm the native species / disrupt the ecosystem
mass extinction
sudden, dramatic loss of biodiversity
in-situ conservation
(in-place ) natural ecosystem is preserved and degradation is prevented
eg. wolves in natural habitat
ex-situ conservation
(out of place) breeding and maintenance of endangered species in artificial ecosystems
eg. tigers in captivity
restoration
repair or reverse degradation, damage, or destruction that has already been done to an ecosystem
niche
subset of ecosystem where a particular species live
distribution
where geographically a species lives
abundance
how many individuals of a species are in a given area
diffusion dispersal
gradual movement of a species over hospital terrain for a period of generations
jump dispersal
movement of an individual across a large distance
secular dispersal
migrant populations evolve into a new species as they disperse from original population
Salt Marsh Video
hypothesis: top-down ecological forces plan an important role in salt marshes
ie. the snails are controlling the growth of the grasses
control group: land without snails
independent: fertilized, unfertilized
dependent: plant growth
Salt marsh ecosystems are maintained by a combination of top-down and bottom-up forces - the comination of snails (top-down) and nutrients (bottom-up) interact to control the amount of marsh grass that grows.
Which "way of knowing" is the primary way of knowing used in science? | |
Perception/Sensory (Empiricism)
Once a theory has been tested over and over for many years, it becomes proven.
False
Sometimes, when people are presented with evidence that contradicts their personal beliefs, they find ways to justify, ignore, forget, or discount this evidence. This is an example of:
confirmation bias
Sal wants to test whether highway noise affects bird feeding behavior. They find two identical sites in the woods, both that are far from the highway and have no noise. The two sites are separated enough that noise will not travel between them. They install bird feeders with "camera traps" that take a photo when the bird visits the feeder - five feeders with cameras at each site. At one site, Sal installs speakers that play a recording of highway noise at the same decibel level as they measured 100 meters from the highway. At the other site, no extra noise is played. After one week, Sal compiles the data from the camera traps and averages the number of visits to the feeders and compares the total number of visits at the site with highway noise to the number of visits at the site with no noise.
What is the independent variable?
whether or not the highway noise is played
Which of the following does not describe scientific process or knowledge?
proof of certainty
repeatable
falsifiable
evidence based
proof of certainty
There are 4 types of biodiversity we discussed in lecture. Which type refers to the number of species?
taxonomic diversity
Which of the following is not one of the 3 domains of life determined using molecular phylogentic analysis?
Prokarya
Eukarya
Archaea
Bacteria
Prokarya
How many times has multicellularity evolved? And in which groups of organisms?
plants, fungi, animals
population density
number of individuals per unit of area or volume
dispersion
patter of spacing among individuals in a population
census
count of a members of a population
Complete Direct Counts
count all of the individuals in a population by observation
very accurate but potentially difficult
possible for small scales or large animals in open areas
density sample
individuals per unit of area/volume
quadrat sampling
the type of species and abundance of each species in a given area/volume are recorded
transect sampling
draw lines across survey area and then count individuals a given distance to either side
volumetric sampling
collect a given volume of water then count
mark-recapture sampling
capture and mark all of the animals during a given sampling event then release them later
indirect counts
when it is not possible to estimate the density of organisms in an area, you can compare relative abundance/density between areas or over time
eg. traps, fecal counts, vocalizations, catches per effort, dens and nests
demography
statistical study of how a population changes over time
survivorship curve
type I = late loss
type II = constant loss
type III = early loss
type I
humans - few offspring, high parental investment, low infant mortality, higher death rates late in life
type II
small mammals and birds- moderate amount of offspring, some parental investment, individuals tend to die at steady rates throughout life
type III
trees, invertebrates - produce many small offspring, little to no parental investment, low likelihood of surviving early life, but those that survive early life tend to live long
growth rate
birth rate - death rate
carrying capacity K
max number of organisms that a region can support without environmental degradation
can decline if a population grows too much
Which of the following statements best reflects empiricism?
Once a phenomenon is rigorously tested and a wealth of evidence is collected, the knowledge gained is considered a permanent fact that cannot be disputed.
What we know to be true is always up for revision based on new evidence.
Truth is subjective and may mean different things to different people, based on their values or beliefs.
Logic and reason are key; if an argument follows correct logic, then it is true.
ANSWER: What we know to be true is always up for revision based on new evidence.
A researcher wants to test if “chemical X” in a popular household pesticide harms frogs by increasing the amount of stress hormone (cortisol) they produce. They have 3 treatment groups: 1) frogs that live in clean water; 2) frogs that live in water exposed to the pesticide containing “chemical X”; and 3) frogs that are exposed to a placebo – the pesticide with all of the inactive ingredients but with “chemical X” removed. They measure the frogs stress hormone levels before exposure to the treatments and then measure it after a week of treatments to see if “chemical X” increases the frogs stress hormone production.
In this case, stress hormone (cortisol) is…
dependent variable
Bob is on a research team trying to determine how common a vegetarian diet is among college students. To do this, Bob and their team go to a different places across a college campus and ask students to take surveys. Bob notices a lot of students lined up outside of a steakhouse across the street from the campus and decides to survey students waiting in line because it seems easier. Bob finds that only 2% of the students he surveyed were vegetarian, while the other researchers on their team found that 20-30% of the students they surveyed were vegetarian.
sampling bias
Dogs (Canis familiaris) and gray wolves (Canis lupus) are sister species to each other on a phylogenetic tree; however, dogs are move evolved than gray wolves because they have been domesticated by humans.
FALSE
Out of the types listed, which are the most abundant type of organism on all of Earth?
vertebrates
insects
plants
fungi
What is the value of biodiversity?
| |||||
| |||||
Production of materials and livelihood for support such as food, timber, and energy | |||||
Greater access to aesthetic values and opportunities for education and recreation | |||||
Regulation of environmental processes including water and soil cycles, air quality, and climate regulation |
Which statement is the most correct?
Ecological processes drive evolutionary responses AND Evolutionary process drive ecological responses
Which of the following is an indirect measure of abundance?
Counting the number of frog calls per hour at a pond to compare the calling rates between ponds
What do we predict might happen if a population of animals exceeds its carrying capacity?
After initially overshooting capacity, the population might fall back below capacity before leveling off right at the original carrying capacity.
After initially overshooting capacity, the animals damage the environment so much that it collapses and cannot heal, causing the population of animals to crash and eventually go extinct.
After initially overshooting capacity, the environment becomes damaged and the population falls back below the original capacity, but then settles at a new lower capacity based on the environmental damage.
Based on the phylogeny of all life on Earth that was made using DNA evidence, the group Eukarya (which includes all known forms of multicellular life, including us) is most closely related to which other group of organisms?
archaea
if population overshoots carrying capacity by a lot
environment is extremely damaged, and population dies
if population overshoots carrying capacity by a good bit
environment is damaged and carrying capacity is reduced
Note
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