NS201 Exam I

Intro to Bio

ecology

ecology

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

1. use sensory means

2. make observation

3. rationalize

4. draw conclusion

5. 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?

	Greater access to aesthetic values and opportunities for education and recreation Production of materials and livelihood for support such as food, timber, and energy
	Regulation of environmental processes including water and soil cycles, air quality, and climate regulation
	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