Ecology Flashcards
Unit 4
Define Habitat
The place where an organism lives. It’s geological location, but more specifically the type of location inhabited (physical conditions)
What are the three different types of adaptations for predators to find, catch and kill prey (examples for each)
- Physical: specialized teeth for piercing and tearing, great eyesight
- Chemical: Venom, pheromones that mimic other species mating scents
- Behavioural: Ambush techniques learned from practice, speed and strenght to overpower
What are the three different types of adpatations for PREY animals to avoid getting eaten? (with examples for each)
- Physical: Camouflage
- chemical: Toxic substances and warning signs through coloration
- Behavioural: Swim or move in tight groups or packs, flee with speed or hide
within three different types of Prey and predator’s adaptations, what can change the fastest?
Behavioural adaptations!
Within three different types of prety and predator’s adaptations, what changes (adapts) the slowest? (elaborate, with reasoning)
Chemical adaptations, becuase new enzymes may be needed or new ways of regulating enzymes, which may take millions of years.
Define Forest canopy
Upper layer of the forest, a place where a tree (tallest) is not affected by the shades of other trees.
What are soem plant’s strategies to obtain light?
- Leading shoot that grows to great heights (be tall)
- Plants grow on branches of other trees
What are epiphytes
They are type of plants which grow on the trunks and branches of trees, it has no roots to the soil
How does epiphytes obtain moisture?
From the plants it grows on, like moss
What do strangler epiphytes do to obtain light?
They climb up the trunks of other trees and out grow their branches so it shades out the leaves of the host tree, causing the death to the host tree
What are some adaptations of plants which grow in the shade (short plants)?
The shade plants are good at absorbing wavelenghts of ligth which are still available.
Define fundamental niche
Area within an organism’s range of tolerance (The biotic and abiotic ranges the organism can live in).
Define realized niche
The actual range that a species occupies due to competition, excluding them from prats of it’s fundamental niche
What would happen to species without any competitors (in relation to fundmental and realized niche)?
Species living without competitors, would occupy the whole fundamental niche.
What when two species have overlapping fundamental niches?
One speices will outcompete the other in all or parts of its fundamental niche.
What happens to the out competed species when two sepies have overlapping fundamental niches?
The outcompeted species will not have a realized niche and will be competitvely excluded from that ecosystem
What will happen to the outcompeted species during competitive exlusion?
It will lead either to the extinction of the weaker compettitor or to an evolutionary or behaviour shift toward a different ecological niche
According to ecological theory, what should be unique for each species to survive? (in terms of realized niches)
To survive, each species must have a realized niche that differes from all other species
Define populations
A group of individual organisms of the same species living in the same area at the same time
can members of the same population interbreed?
Yes, normally ithey can interbreed with each other
How are populations normally seperated by?
Population are often separated by geographical barriers (water, mountain)
What is the difference between speices and population?
Species are organisms that can interbreed, while population are members of a single species
Can we count every organisms? Why?
No, it is nearly impossible since organisms camouflage, move and haveare spread over vast areas.
What is random sampling?
Where every mmeber of a population has an equal chance of being selected.
How do we reduce sampling error when random sampling?
By avoiding unconscious bias (i.e. use a random number generator on a phone app).
what is a method of quadrat sampling?
Quadrat sampling involves repeatedly placing a quadrat frame habitat and recording the number of individuals each time it is placed.
When is the use of quadrat sampling appropriate for estimating population size?
It is only appropriate for estimating population size for sessile organisms that does not move
When is the use of capture-mark-recapture method appropriate for estimating population size?
When estimating the population size for motile organisms which move around constantly
What is Lincoln Index?
It is a formula used to estimate population size for capture-mark-release-recapture method
What is formula of Lincoln Index?
Population size estimate = (M x N) / R
M: Number of individuals originally caught and marked
N: Total number of individuals recaptured
R: The number of marked individuals recaptured
What happens when resources become scarce?
The members of a population will compete for it
Define carrying capacity
The maximum size of a population that an environment can support
Define limiting factor
A factor which limits the size of a population. Anything that limits a population’s size and solows or stops it from growing.
What happens when there are too few resources?
it will lead to individuals being unable to get basic needs and die, reducing population size
What are the typical limiting factors in ecosystems for plants?
water
light
soil nitrogen
what are typical limiting factors in ecosystems for animals?
water
space (for breeding)
food or space to obtain food
dissolved oxygen
What is one of the reasons for the fluctuating of population’s size?
The population could fill an ecological niche which hasn’t been occupied before and then ecological changes will cause a decrease
How can population size remain overally stable?
Due to negative feedback control
What are the two types of factors which can increase or decrease populations
Density independent factors
Density dependent factors
Define density dependent factors
factors which have an increasing effects as populations grows larger.
What does density dependent factors do?
They push populatin towards its carrying capacity. They are the basis of negative feedback mechanisms
Why is the density dependent factors basis for negative feedback?
They reduce larger populations and allow smaller populations to increase
what is density independent factors
same effect not matter the population level
What does the PANDA stand for, for density dependent factors?
P- Predators
A- Availability of resources
N- Nutrient supply
D- Disease
A- Accumulation of wastes
What does the PAW sand for, for density independent factors?
P- Phenomena (natural disasters)
A- Abiotic factors (temeprature, CO2 levels)
W- Weather conditions
What does reproduction tends to cause?
An exponential growth in populations
In most populations, what does density dependent limiting factors tend to lead to?
Negative feedback affects that prevent exponential growth.
What does the s-shaped growth curve represent?
Logistical growth, with stable populations occupying a fixed geographic space
What happens during the exponential growth phase of a sigmoid growth curve, and why does it happen?
Initally, the population growth will be slow as there are few reproductive individuals that are likely widely dispersed
what key stages does the sigmoid growth curve typically follow?
An exponential growth phase, a transitional phase and a plateau phase.
What happens during the transitional phase of a sigmoid growth curve, and why does it happen?
As the population continues to grow, resources eventually become limited, which leads to competition for survival
What happens during the plateau phaseof a sigmoid growth curve, and why does it happen?
Evnetaully, the increasing mortality rate equals the natality rate and population growth beocmes static.
The population has reached the carrying capacity, with limiting factors keeping the population stable.
Define intraspecific relationship
An interaction between individuals of the same species
Define community
A group of populations living together in an area and interacting with each other
define competition
an interaction between two individuals after the same resource.
What is cooperation?
Cooperation can happen in a variety of ways (more so in animals than plants). It is advantageous because all benefit.
define herbivory
primary consumer feeding on producers. The producers may or may not be killed.
define predation
one consumer species killing and eating (predator) another consumer speices (prey)
define interspecific competition
two or more species using the same resource, thus reudcing that is available to each
define mutualism
two species living in a close association, with both benefiting
define parasitism
one specie (parasite) living inside or on the outer surface of, another species (the host) and obtaining food from them. The host is harmed and teh parasite benefits
define pathogenicity
one species living inside another and causes a disease/infection in the host
define endemic species
species that occur naturally in an area, density dependent factors usually regulate them
define alien species
species introduced by humans (deliberately or accidentally) which are often not effectively regulated (natural predator/pest is not present), the impacts could be devastating.
what does competitive exclusion principle predict
it predict that two species can’t occupy the same niche indefinitely
how does a species become invasive?
An alien species must be successful in the competition for resources with endemic species and lead to the endemic speices occupinga smalelr realized niche (ppoulation drop and may even become extinct)
when can we deem the chi squared test to be valid?
when all the expected frequencies are 5 or larger and the sample was taken at random from the population.
what does it mean when a chi squared test exceeds the critical region?
It means that there is a relationship between the species (suggesting competition) and we must reject the null hypothesis saying that there is no relationship.
what is the formula to calculate the chi squared value?
Chi squared value = sum of ((F.0 - F.E)^2)/F.E
What is the formula to calculate the expected frequency
expected frequency = (row total x column total) / grad total
what are the two uses of chi square test?
- testing for independence or association
- testing for goodness of fit (in genetics unit)
why won’t the population of prey change much when they are being killed by a predator?
new prety born at about same rate as prey are killed
Cyclical oscillations, what are the 4 interactions of a predator - prey cycle?
- Increase in prety numbers increases food availbaility for predators, so predator numbers rise
- A rise in predator numbers increases predation of prety, so prety numbers fall
- A fall in prey numbers decreases food availability for predators, so predator numbers fall
- A fall in predator numbers decreases predation of prey, so prety numbers rise
where are the cyclical oscillationsn in predator and prety populations mostly seen?
They are mostly seen in habitats where weather conditions vary from year to year
example of a top down control
an increase in predator will decrease prey in lower trophic levels
example of a bottom up control
producer population may be limited by amount of nitrogen in the soil
what is essential for cell growth ?
Primary metabolites, which are substances produced by metabolic pathways of a living thing
what are secondary metabolites
They are substances produdced only by some organisms and these metabolites are not needed for growth but have other functions.
where are secondary metabolites produced by?
They are produced by pathways that only exists in some taxonomic groups
what are the two groups of the secondary metabolites
antibiotics and allelopathic agents
what are antibiotics?
They are secreted by microorganisms to kill or prevent growth of other microorganisms
what are allelopathic agents?
allelopathic agents are secreted into soil by plants to kill/prevent the growth of neighboring plants
what do living organisms depend on interactions with other organisms (+ abiotic) for survival?
the supply of energy and chemical resources.
They also depend on the abiotic world to provide air, water, soil etc.
define ecological system
a set of interacting components
what are the two types of ecological system?
open system and closed system
What happens to resources in an open system?
resources can both enter and exit (for both chemical substances and energy)
What happens to resources in an closed system?
energy can enter or exit, but chemical resources can’t be removed or replaced.
are ecosystem open or closed systems?
open systems
what is the initial source of energy for most ecosystems?
sunlight!
why do photosynthesis rates vary around the world?
becuase the intensity of sunlight vaires throughout the world and the % of light harvested for photosynthesis varies as well.
how does living and non living matter effect the light penetration in marine ecosystems
They reduce the light penetration
which ecosystems are the exceptions to light being the principal source of energy in ecosystems?
marime and freshwater ecosystems and caves
how are energy supplied inside a cave without light?
through streams entering a cave, brining dead organic matter
what is the producers in a sealed caves?
archaebacteria
how do archaebacteria gained chemical energy?
through chemosynthesis, producing organic compounds from chemical reactions involving inorganic substances
what is a food chain?
sequence of organisms showig who eats whom , each organism in the chain feeds on the previous one
in a which food chain, which has absorbs the most sunlight and how?
producers absorbn most sunglight. They use chlorophyll to turn light energy to chemical energy (photosynthesis)
how do consumers obtain energy?
from the carbon compounds in the organisms they eat
define apex predator
last consumer in the food chain, nothing kills or eats them
define food web
a diagram that shows how food chains are linked together into more complex feeding relationships
why is food web more representative of actual feeding pathways within an ecosystem?
organisms can have more than food soruce adn they can also have more than one predator
define trophic level
the position an organism occupies in a food web, its feeding level.
what are decomposers
they are organisms that obtain energy (carbon compounds) by breaking down dead organisms
define saprotroph
an organism such as mushrooms that release digestive enzymes into dead organic matter and digest externally and absorb the nutrients
why are saprotrophs considered as decomposers?
they break down complex insoluble carbon compounds into simpler soluble ones.
what are autotrophs?
organisms that make carbon compound sthemselves, “self-feeders.”
When autotrophs build organic macromoelcules, what do they require?
anabolic reactions and external energy source; light and chemical reactions
why do autotrophs need an external energy source to create carbon compounds?
Inital reduction reactions of the calvin cycle are endothermic and linking of simple carbon compounds into larger more complex compounds by condensation reactions are also endothermic
what are photoautotrophs
autotrophs that use light as the energy source
what are chemoautotrophs
autotrophs that use xothermic inorganic chemical reactions as the energy sourse
what are some photoautotrophs?
organisms that perform pohotosynthesis
what are some chemoautotrophs
prokaryotes, both bacteria and archaebacteria
define assimilation
the process of absorbing carbon compounds and making them part of the organism
what are heterotrophs
they are the organisms which obtain their carbon compounds by digesting (consuming) other organisms and then using them to build macromolecules (like starch or protein)
how does heterotrophs work in terms of hemoglobin.
A person needs to make hemoglobin. To do this, they must eat meat, digest it into amino acids that are now small enough to absorb into the bloodstream. Then, the cells absorb the amino acids and use the cell machinery to put the correct amino aicds together in the correct order to make hemoglobin
what is the requirements for the molecule for the assimilation to occur?
the molecules must be small and soluble enough to pass across cell membranes.
