freshwater exam 4

define population

group of individuals of a single species inhabiting a specific area

define principle of allocation

each individual organism has a limited quantity of resources that it can use for all necessary life processes

define niche

summarizes environmental factors that influence growth, survival, and reproduction of a species

define fundamental niche

defines physical conditions under which a species may live in the absence of interactions with other species

define realized niche

defined where a species lives by taking into account the physical conditions as well as interactions with other species (ex. competition)

understand limits to population distribution and density

physical environment limits geographic distribution of a species

no single species can tolerate the full range of earths environments

growth, reproduction, acquiring nutrients and resources, escaping predators

what would limit the distribution of an aquatic organism?

physical conditions: light, temperature, water movement, salinity, oxygen, nutrient availability

species interactions: competition, predation

define interaction types

predation, competition, mutualism, commensalism

predation

harms one species, helps another (-,+)

competition

harms both species (-,-)

mutualism

helps both species (+,+)

commensalism

neutral benefit to one, helps the other (0,+)

explain difference between direct and indirect interactions

direct interaction: - or + interaction between two species without the involvement of an intermediary

indirect interaction: - or + interaction between two species that is mediated through a third species

direct interactions examples

predation/parasitism/herbivory

competition

mutualism

indirect interactions examples

trophic cascades

apparent competition

indirect mutualism or commensalism

determine trophic level from a provided food web

follow food web and separate into groups of primary producers, primary consumers, etc

food webs

summary of feeding interactions within a community

trophic level

groups of species that have similar ways of obtaining energy

describe how the microbial loop recycles dissolved organic matter in the epilimnion

The microbial loop describes the process where bacteria decompose dissolved organic matter (DOM) in the epilimnion, converting it into microbial biomass. These microbes serve as a food source for higher trophic levels, effectively recycling nutrients back into the aquatic ecosystem.

explain energy flow through a productive pyramid snd why herbivore require less energy input/biomass

Energy flow in a productive pyramid illustrates how energy decreases as it moves from producers to higher trophic levels. Herbivores require less energy input because they occupy a lower trophic level, utilizing energy directly from plant materials, which are more abundant and efficient in energy conversion compared to the energy needs of carnivores.

understand the 10% rule of energy transfer

The 10% rule of energy transfer states that when energy is passed along a food chain, only about 10% of the energy from one trophic level is transferred to the next level. The remaining energy is lost as heat or used for metabolic processes.

why is 10% an average? and where is energy lost?

In ecological terms, 10% is often referred to as the average energy transfer efficiency between trophic levels in an ecosystem, known as the 10% rule. Energy is lost primarily through metabolic processes, heat production, and uneaten biomass as it moves from one trophic level to the next.

understand the relationship between biomass and productivity

This concept refers to the way in which the amount of living organic material (biomass) in an ecosystem is connected to the rate of production of new organic material (productivity) through photosynthesis or other processes.

understand why some habitats have more primary productivity/trophic levels than other habitats

Factors such as nutrient availability, light conditions, and temperature influence the levels of primary productivity and trophic diversity in different habitats. Ecosystems with optimal conditions tend to support more varied and productive food webs.

examine indirect effects of top-down and bottom-up control

A method to assess how predators (top-down) and resources (bottom-up) influence ecosystems by measuring their impact on various trophic levels and community structure.

describe limitations placed on consumers for obtaining energy and nutrients

photosynthetic rates level off at photon flux density saturation, reaching maximum photosynthetic rate. photosynthesis is described by the chemical equation; autotrophs are constrained by temperature, light, water, and essential nutrient availability

herbivores: must consume massive amounts of plant biomass to compensate for large differences between food nutrient content and consumer metabolic requirements, overcoming high carbon to nutrient ratios

detritivores: food material is carbon-rich and energy dense but poor in nitrogen

carnivores: stoichiometry of prey closely matches consumer tissue requirements for carbon, nitrogen, and phosphorus

understand functional response curves

type 1: prey consumption increases linearly with prey density, no satiation, no handling limitations

type 2: prey consumption decelerates into a plateau due to handling time or satiation limitations, most common response among predators

type 3: sigmoidal response curve, S shape, consumption is depressed at a low prey density due to search image formation, satiation or handling limitations; learning, switching, or prey refuges

explain optimal foraging theory, including it’s predictions

models feeding behavior as an optimizing process, if organisms have limited access to prey, then natural selection is likely to favor individuals within a population that are more effective at acquring energy, if energy supplies are limited, organisms cannot simultaneously maximize all life functions, must compromise between competing demands for resources

prediction: attempts to predict what consumers will eat, and when and where they will feed

connect evolution and adaptation to the development of defense mechanisms

Adaptation refers to the evolutionary process by which species increase their fitness in response to environmental pressures, leading to the development of various defense mechanisms that enhance survival against predators and environmental challenges.

define competition

must demonstrate that species share a limited resource or that presence of a competitor alters resource use patterns and must demonstrate that limitation in this resource ultimately negatively affects a population

types of competition:

indirect/scramble: individuals compete indirectly by reducing the supply of a shared resource

direct/interference: species compete by directly interfering with the ability of competitors to use a limiting resource

apply the niche concept to competitive exclusion principle

two different species that use a limiting resource in the same way cannot coexist indefinitely

fundamental niche: the niche defined by physical, chemical, and biological aspects of the environment except for interspecific interactions such as competition, predation, and parasitism realized niche: what remains available to the species once competition, predation, and parasitism are taken into account

given the amount of competition in nature explain how species are able to coexist

resource partitioning, division of resources to avoid interspecific competition; use of limiting resource in different ways, vary time, location, method, and prey size

define keystone species

low biomass, but large effects on community structure

if keystone species reduce likelihood of competitive exclusion, their activities would increase the number of species that could coexist in communities

keep population number low

define carrying capacity

maximum population of a given species that a particular habitat can sustain indefinitely

connect keystone species and carrying capacity

Keystone species are organisms that have a disproportionately large impact on their ecosystem relative to their abundance, influencing the populations of various other species and helping to maintain the structure of their ecological community. Carrying capacity refers to the maximum number of individuals of a particular species that an environment can sustainably support, which is often affected by the presence and roles of keystone species.

define and provide examples for three main categories of predation defenses exhibited in aquatic animals

The three main categories of predation defenses in aquatic animals are: 1) morphological defenses, like body spines or toxins; 2) behavioral defenses, such as schooling or hiding; and 3) chemical defenses, which include the release of toxic or repellent substances.

describe generalized population growth

Generalized population growth refers to the increase in the number of individuals in a population over time, typically represented by a growth model such as exponential or logistic growth. It reflects how populations expand based on factors like birth rates, death rates, and carrying capacity.

connect declines in competitive exclusion to an increase in diversity

The concept of competitive exclusion states that two species competing for the same limited resource cannot coexist at constant population values. When competitive exclusion occurs, species that are less competitive may decline or be driven to extinction, which can paradoxically lead to an increase in diversity as remaining species can exploit different niches or resources.

name different types of keystone species along with the mechanism of why community diversity increases when they are present

Keystone species are organisms that have a disproportionately large effect on their environment relative to their abundance. Different types include predators like sea otters and wolves, herbivores like starfish, snail(herbivore), and fish, and ecosystem engineers like beavers, american alligator, and crayfish; their presence increases community diversity by maintaining the structure and balance of ecological interactions.

define disturbance

any discrete event in time that disrupts an ecosystem, community, or population structure and changes resources, substrate availability, or physical environment

define press in terms of disturbance

long lasting/continuous

define pulse in terms of disturbance

punctuated, temporary

outline impacts that climate change will have (is currently having) on freshwater ecosystems

global warming

glacial retreat

decreased snow cover

sea level rise

extreme weather events

ocean acidification

define weather in terms of climate change

set of physical conditions such as temperature, precipitation, humidity and other factors in a given area for short periods of time

define climate in terms of climate change

an area’s general pattern of atmospheric conditions over periods of ranging from 30 to thousands of years

main cause of our current climate change

increases in greenhouse gases in the atmosphere, namely through the burning of fossil fuels

changes in hydrology

droughts

flooding

decrease in mountain snowpack/earlier melt

warmer water temperatures impacting freshwater ecosystems

metabolism

ice over

length of seasons

oxygen content

anadromous

migrate from the ocean into freshwater rivers to spawn

foraging autotrophs are limited by:

temperature, nutrient availability, water availability, carbon dioxide availability, and light availability

foraging heterotrophs prey characteristics

defense mechanisms, density, handling time, energetic value, size

foraging behavior heterotrophs predator characteristics

hunger level, stomach capacity, mouth size, vulnerability to other predators

foraging behavior heterotrophs abiotic characteristics

temperature, availability of predation refugia

coevolution

defense mechanisms evolve because they confer a reproductive advantage

coevolutionary arms race

a population responds to predation pressure through better adaptations over generations

defensive allomones

chemicals that affect another species to the benefit of the producer; toxic or bad tasting chemicals

kairomones

compound produced by predators that affect the behavior, morphology, or life history characteristics of prey species

alarm chemicals

chemicals that are produced by damaged or stressed organisms that nearby prey items respond to

diel verticle migration

organisms move up to the epilimnion at night and return to the hypolimnion during the day

eutrophication

accelerated nutrient enrichment of aquatic systems, leading to enhanced primary production

phytoplankton

produce numerous new generations over a year, produce new tissue at a fast rate, which is then consumed

ecosystem

biological community, plus all the abiotic factors influencing that community

abiotic factors: temperatures, nutrients, light levels, pH, dissolved oxygen

primary productivity