Unit D Test Flashcards
What is dynamic equilibrium?
A population is in dynamic equilibrium when the number of deaths and births is the same resulting in no significant population change
What are density-dependent factors and density-independent factors
Density-dependent factors are factors that only affect dense populations of organisms such as diseases. Density-independent factors are factors that affect a population equally regardless of size like natural disasters
What is carrying capacity
Carrying capacity refers to the maximum number of individuals that can be supported by an ecosystem’s finite resources. if the carrying capacity is exceeded, competition will happen and a population crash is imminent
Define fecundity
An organisms ability to produce healthy offspring
Define non-random mating
occurs when the probability that two individuals in a population will mate is not the same for all possible pairs of individuals
Define natural selection
The processes through which populations of living organisms adapt and change
Define gene pool
A gene pool refers to all the genes available to an individual in a particular species
Define environmental resistance
The collective name given to all environmental factors that can limit a populations ability to grow
What is migration
The greater the difference in allele frequencies between the resident and the migrant individual, and the greater the number of migrants, the greater the effect the migrants will have in changing the genetic constitution of the resident population
What is geographic isolation
When members of the same species are separated geographically
What is Gause’s principle?
Gause’s principle is founded on the idea that if two species that occupy the same ecological niche are in one ecosystem, one species will be “dominant” over the other and the less fit species will be outcompeted
How do adaptations occur as a result of natural selection?
Individuals who are not suited to their environment will not live to reproduce and pass on their genes. As a result over time the population of a species will adapt to become better suited to its environment
What is symbiosis and what are the three types
An interaction or “relationship” between two species
-commensalism: a biological relationship between two species in which one organism benefits and the other is neither harmed nor benefits
-Mutualism: A relationship between two species where both will benefit in some way
-Parasitism: A relationship between species where one organism, the parasite(who benefits) lives on or inside another organism(the host) and harms it in the process
What are the two types of competition and their definitions?
-Interspecific competition: competition between different species
intraspecific competition: competition between the same species
What is the difference between mimicry and camouflage
Mimicry: Mimicry is an evolved resemblance between an organism and another object, often an organism of another species. This may involve morphological, physical or behavioural traits
Camouflage: A defence mechanism or tactic that organisms use to disguise their appearance, usually to blend in with their surroundings. Organisms use camouflage to mask their location, identity and movement.
Mimicry is a species attempting to pass as another species or object, whereas camouflage is a species attempting to better blend in with their surroundings
What shape will the graph of exponential growth be
J shaped: Rapid increase with no limiting factors
What shape will the graph of logistical growth be
S curve: lag phase (reproduction is low), growth phase(growth rate spikes), stationary phase(population has reached its carrying capacity and levelled out)
What is a r-selected species
A species that lives in rapidly changing environments, is short-lived, has a highly varying population size, has a density-independent mortality rate, has low competition, reproduces once at a young age, does not care for its offspring, produces high numbers of offspring, has a j-shaped population curve, has a smaller body. Ex insects, salmon
What is a K-selected species
A species that lives in a stable and pridectibal environment, is often long-lived, has high competition, has density-dependent mortality, reproduces multiple times later in life, cares for young, lower number of offspring, has a Large body size, and has an s-shaped graph.Ex humans, elephants
What is the difference between primary and secondary succession
Primary succession: The changing of an environment from bare rock(no soil) to a complex community( multiple plant/animal species)
Secondary succession: The return of life to an area that has lost its vegetation
What is the difference between pioneer and climax species
A pioneer species is the first species to emerge after succession like moss, whereas a climax species is a more complex species supported by a fully recovered ecosystem
What is the formula for growth rate
gr=ΔN/T
What is the population for population density
Dp=N/A
Dp=N/V
What is the formula for per capita growth rate
cgr=ΔN/NO
What five conditions impact the Hardy-Weinberg genetic equilibrium
The Hardy-Weinberg principle states that allele and genotype frequencies in a population will remain constant and applies to populations where genotype and allele frequencies can be calculated. The factors that affect this equilibrium are: population size, migration, mutations, natural selection, non-random mating,
What are the formulas for gene and allele frequency
Gene frequency: p^2(AA) + 2pq(Aa)+q^2(aa)=1
Allele frequency: p(A)+q(a)=1
What is the difference between gene and allele frequency
Gene frequency is a measure of the genotypes and allele frequency is a measure of the rarity of alleles within a populations gene pool
