Unit 8: Ecology flashcards
R-selection
Parenting where lots of babies are produced with the parents not putting a lot of effort into each one.
K-Selection
Parenting where few babies are produced but parents put a lot of effort into making sure they survive.
Altruistic Behaviors
Behaviors that reduce an individual’s fitness but increases fitness of others in population
Inclusive Fitness
Including reproductive success of relatives as well as your own reproductive success.
Kin Selection
Name for selection that prefers altruistic behaviors and increases inclusive fitness
Reciprocal Altruism
Individuals act altruistically with expectation that others will reciprocate at some point.
Differs from inclusive fitness theory.
dN/dt
Population growth
dN/dt =
B - D
(Births minus Deaths)
r
Per capita growth rate
r =
(B-D)/N
Initial growth in exponential growth
lag phase
Density Independent
Factors that limit populations regardless of population density.
Density Dependent
Factors affect population growth differently depending on population density
Positive Density Dependent
Population density can increase the growth rate of a population
Negative Density Dependent
Population density can decrease the growth rate of a population
Logistic Growth
As population approaches carrying capacity, growth rate slows.
Any time a population is over K, their population will…
decrease.
Is k constant?
no! can change bc of permanent changes in food availability or increase/decrease in habitat size
Survivorship Curve
Used to visualize how the # of individuals in a population drops over time.
Type 1
Organisms that have a high survival rate when they are young, but as they grow older they die off
Ex: Humans
Type 2
Organisms that die at around the same rate no matter what age they are
Ex: Birds
Type 3
Organisms where the majority die at a young age, and the death rate then slows as they grow older
Ex: Trees
Niche
Set of conditions in which an organism can survive and reproduce due to its inherited adaptations
Includes habitat, resources, etc.
Fundamental niche
Entire range of abiotic conditions where a species can technically survive and reproduce
Realized Niche
Subset of fundamental niche where the species actually lives when accounting for biotic factors.
Competition
(-/-)
Two species try to use the same limited resource. Reduces population of both species
Results in niche portioning or elimination of one species from ecosystem
Predation/Herbivory
(+/-)
When one organism eats another.
Coevolution
2 or more species change in response to selective pressure from each other.
Evolutionary “arms race” between prey and predators
Symbiotic relationships
Close, prolonged association between organisms of different species
Parasitism
(+/-)
When one organism benefits off of the harm of another organism.
Commensalism
(+/o)
One species benefits, while the other is neither benefited nor harmed
Mutualism
(+/+)
When both species benefit from the interaction
Obligate Mutualism
The species are entirely dependent on each other
Facultative mutualism
The species benefit from their relationship, but could survive without each other.
Amensalism
(o/-)
Where one species is harmed, while the other is unaffected.
Autotrophs
Producers who make their own food with energy and inorganic molecules
Heterotrophs
Consumers who eat other organisms
Detritivores
Animals who feed on nonliving organic matter and break it into smaller pieces
Decomposers
Bacteria and fungi that chemically break down detritus and return inorganic molecules to environment
In food webs, arrows go from
prey to predator
OR
plant to herbivore
10% rule
only 10% of the energy taken in at 1 trophic level is available to the next level. Rest is lost as heat.
Productivity
The rate at which plants and other photosynthetic organisms produce organic compounds.
Changes depending on climates/atmosphere
Four parts of carbon cycle:
1) Photosynthesis: Plants absorb CO2 and convert it to glucose
2) Respiration: Organisms release CO2 into atmosphere
3) Decomposition: Dead organisms break down and release carbon
4) Combustion: Burning fossil fuels
Nitrogen is needed for:
Nucleic acids and Proteins
Three main parts of Nitrogen cycle
1) Nitrogen in the air is absorbed into the ground, which is made usable to organisms through bacteria
2) Plants take in the usable nitrogen in the soil
3) Consumers eat the plants, and get their nitrogen from there
Phosphorus is needed for:
Lipids (phospholipids) and nucleic acids.
4 main parts of Phosphorus cycle:
1) Rocks release phosphorus into ground
2) P is made available in the soil through decomposers breaking down organic matter
3) Plants take up phosphorus through soil
4) Consumers get it through eating plants and each other
TACT (water)
1) Transpiration:
Water evaporates from leaves creating negative pressure
2) Adhesion:
Water sticks to walls of vessels
3) Cohesion:
Water molecules stick to each other
4) Tension:
Pull from transpiration draws water upwards
How do plants control transpiration?
Opening and closing their stomata
Keystone species
Species that their ecosystem rely heavily on.
Effects of KS are disproportionate to their abundance
Invasive species
Nonnative species that overgrow and cause destruction to ecosystems.
Trophic Cascade
Triggered by the addition or removal of a species into/out of an environment.
Causes drastic changes to other organisms.
+/- on solid line
organisms have direct impact on each other
+/- on dotted line
organisms have indirect impact on each other.
Bottom Up Control
A lower trophic level in the food web affects the higher trophic levels via resource restriction
Top Down control
A higher trophic level in the food level affects lower trophic levels through predation
Biodiversity is measured by:
Species richness (# of species in particular location)
Species diversity (How evenly distributed organisms of different species are)
Higher value of Simpsons Diversity Index =
More biodiverse and healthier ecosystem
Extinction vortex
Environmental changes -> smaller pop.
smaller pop. -> inbreeding + genetic drift (bottleneck and founder effect)
genetic drift -> less bio/genetic diversity
less diversity -> lower overall fitness, lower rates of evolution
Many individuals die -> lowering birth rates and raising death rates
This makes the population smaller again, continuing the cycle until extinction.
r- selection happens in ____ environments, while k-selection happens in ____ environments
unstable, stable
