Bio 30 Final review Unit D Flashcards
What is Natural selection
The processes through which populations of living organisms adapt and change
What is genetic drift
A mechanism of evolution in which allele frequencies of a population change over generations due to chance
What is gene flow
“gene migration” or “allele flow” is the transfer of genetic material from one population to another
What is non-random mating
occurs when the probability that two individuals in a population will mate is not the same for all possible pairs
What is the bottleneck effect
“genetic bottleneck” is a sharp reduction in the size of a population due to environmental events like natural disasters, or human activities. This reduces the genetic variation of a population
What is the Founder effect
The loss of genetic variation that occurs when a population is established by a very small number of individuals from a larger population
What is Migration and how does it affect the gene pool
Migration is when a population of a species moves from one populated area to another. The larger the number of migrant individuals and the greater the difference in allele frequencies the greater the effect the migrants will have on changing the genetic constitution of the resident population
What are Mutations and what effect do they have on the gene pool
Mutations are a genetic defect resulting from an error in DNA replication. They are a strong force for introducing new alleles and a weak force for changing allele frequencies
What is geographic isolation
This is when members of the same species are separated geographically
What is reproductive isolation
This is when populations of the same species experience Drastically different changes in allele frequencies resulting in them no longer being able to reproduce
How can geographic isolation lead to reproductive isolation
When populations of the same species are separated geographically, The environmental pressures of the two populations will be different. This means that natural selection will favour different traits based on the location of the population; this causes the gene frequencies of the populations to change over time. Eventually, the gene pools of the populations will change enough that members of each respective location can no longer mate.
How do mutations result in a changing gene pool?
If a mutation provides a benefit, natural selection will begin to favour the mutated trait and it will become more commonplace in the gene pool.
What are the types of competition
-Interspecific competition: competition between different species
intraspecific competition: competition between the same species
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
What is symbiosis and the different 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 Defense mechanisms
Mimicry: evolved resemblance to another organism or object, can involve morphological, physiological and behavioural traits
Camouflage: a tactic used to disguise their appearance, usually to blend into their surroundings. used to mask location, movement and identity
Protective toxins: some organisms are able to release and inject toxic chemicals to defend themselves from danger
What is the difference between mimicery and camouflage
If an organism uses mimicry, it is trying to be perceived as something else. If an organism uses camouflage, it is trying to not be perceived at all
What are the two kinds of succession and the difference between them
Primary Sucession: The changing of an environment with no life to a complex community
Secondary Sucession: the return in stages to a stable climax community in an area that’s lost its vegetation but not its soil
What is a population
A group of organisms of the same species that live in the same habitat at the same time.
What is a community
all organisms of various species that share a habitat at the same time
What is an ecological niche
An organism’s role in an ecosystem (place in the food web, breeding area, time of day when most active)
What are the different kinds of population distributions
Clumped: individuals in a population are more concentrated in certain parts of the habitat
Random: Individuals are spread throughout a habitat in an unpredictable and patternless matter
uniform: Individuals are equally spaced throughout the habitat
What are the biotic factors that affect population growth
Gender ratio
Mate avalibity
gestation period
estrous period
clutch or litter size
fecundity
What are the abiotic factors that affect population growth
-food supply
-availability of shelter
-water supply
-law of the minimum: growth of a population is controlled by its least available resource
-sheldfords law of tolerance: some species can only thrive in a certain range of abiotic factors
-density dependant factors
-density-independent factors
What is a 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 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
What is Environmental resistance
The collective name given to all environmental factors that can limit a populations ability to grow
What is the difference between open and closed populations
Open: a population in which change in number and density is determined by natality, immigration, mortality, and emigration
Closed: a population in which change in number and density is determined only by morality and natality
What is exponential growth, its graph shape and the requirements for it
Exponential growth describes the rapid uptick in population size of a closed population, it’s characterized by a j shaped graph curve
What is logistic growth and its graph shape
S-shaped graph representing normal population growth
What are density vs density-independent factors
Density-dependent factors 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 fecundity
An organism’s ability to produce healthy offspring
What is a gene pool
A gene pool refers to all the genes available to an individual in a particular species
What is the Hardy-Weinberg principle
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,
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 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, has a lower number of offspring, has a Large body size, and has an s-shaped graph.Ex humans, elephants
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 the 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 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
