Population and Community Dynamics Flashcards
Whats a population
Same species at same place in same time
> specific time ex. July 2020
> Species can have variety not identical
Whats a gene pool
all of the allels for all of the genes in a population at any one time
> all alleles: BB, Bb and bb genotypes all at one time
Who’s Darwin, what did he find and what does it mean
Fount out abt Natural Selection:
> that new variants of species arise continually
> those that can thrive adapt and produce more offspring lead to changes in population, those who cant die off
> Mandels work helped explain this
What is the Hardy-Weinberg Principle and show
> what 5 conditions must be met
Model that shows wether evolution has occurred in a population
Allele gene frequency will remain same (no evolution) as long as :
1- Very large population
2- Random mating
3- No mutations
4- No migration
5- No natural selection
Formula for calculating allele frequency and what each letter represents
p+q=1.00
p- dominant allele
q- recessive allele
Formula for calculating genotype frequency and what each letter represents
p^2 + 2pq + q^2
p^2- frequency of homozygous dominant individuals
2pq- frequency of heterozygous individuals
q^2 - frequency of homozygous recessive individuals
What are the causes of Gene Pool Change ?
Micro evolution: gradual change in gene (allele) frequency with a population
> Mutations, Genetic Drift, Gene Flow, Non random mating, Natural selection
What are Gene pool change mutations
> most occur?
>how inherited?
>Benefit?
Original source of genetic variation
> Most occur within somatic cells and die within individual
> inherited if in gametes
> can provide selective advantage
What is gene pool change genetic drift
> 2 genetic drift situations: Founder and Bottleneck what are they and differences
Changes in a gene pool in a small (sub) population due to chance events that change allele frequency with
> Founder: small number of individuals colonize a new area = gene pool dosent contain all genes from parent population
> Bottleneck: results from rapid decrease in population size caused by natural disasters or hunting > loss of gene pool diversity
What is the Founder effect
A gene pool change = genetic drift when a small number of individuals colonize a new area and the new gene pool dosent contain all equal representation of all genes from parent populations
Whats the Bottleneck effect
A gene pool change= genetic drift situation where it results in a rapid decrease in population size caused by natural disasters or hunting causes loss of diversity
Whats the gene pool change of gene flow caused by
Caused by immigration or emigration that decreases or incrases genetic diversity
Whats the gene pool change of non random mating and benefits/disadvatages
When idividuals with certain more desired characteristics mate, those characteristics increase chance of mating
> more homozygous individuals produced in interbreeding
> harmful allels more likely expressed
Whats the gene pool change cause of natural selection
> Some individuals will produce more offspring then others: cause grater fitness and selective advantage
What is succession
> the two types
Gradual change in the vegetation of an area: little biodiversity to stable larger biodiversity
1- Primary succession
2- Secondary succession
What is Primary succession
Gradual change in the vegetation of an area- from an area with no community previously existing (no soil just rocks) > weathering of rocks produces soil - Slow process
What is secondary succession
Community is partially or completely destroyed - fast process as significant soil and seeds exist
ex. forest fire
Whats Climax community
A point reached in succession with stable point with not much change
What are the 2 stages of succession
Pioneer stage and Climax stage
> Pioneer is when species (small- grasses) enter and grow , starting vegetation > create microclimate for other species > when they die they increase soil and water storage for larger species
> Climax stage: stable plant community lots of diversity- not much change max reached
Types of populations:
> what do they each mean
Open population: changes in birth, death, immigration and emigration > natural
Closed Population: changes in birth and death only, no immigration or emigration (cant leave/enter) > rare
What is population growth: biotic potential
> highest possible growth rate, no limits, resources are abundant, exponential growth ( j shaped curve on graph) , birth> death
Life Strategy: R selected is what
-Exponential growth (J-curve)
-increase population size rapidly
- Many offspring and low parental care
- Short lifespan and small organisms
Life strategies: K selected is what
- Logistic growth ( S- curve)
- Few offspring: slow growing with lots of parental care
- Larger size organisms and long lifespan
What is a carrying capacity
Maximum stable population size that a particular environment can support over a long time
What’s environmental resistance
Biotic and abiotic factors that limit population size and result in a logistics growth (S curve)
What are density independent factors that limit population growth
Abiotic - non living factors that effect everybody in a population
ex. weather conditions , flood, drought etc.
What are density dependent factor that limit population growth : intraspwcific vs inter specific
Biotic - living factors
1- Intraspecific competition: within individuals of the same species
2- Interspecific competition: between individuals of a different species
What is intraspecific competition
density dependent biotic factor within individuals of the same species
What are interspecific competitions
Density dependent biotic factors between individuals of different species
What does N, D and A or Vrepresent in equation D= N/AorV for size and densityy of populations
N-Population size # of organisms
D- population density
V/A- per area or volume
Changes in population size formula
what do variables represent
🔺N= (B+I)-(D+E) or Nfinal-Ninitial
B- births I- immigration
D- deaths E- emigration
Growth rate calculates what
> Formula and variables
How quickly a population size is changing
> gr= 🔺N/🔺t or (Nfinal- Ninitial) / (Year final - year initial)
have to calc 🔺N and t🔺 for it
Cgr - growth rate per capita us calculating:
> formula and variables
Amount of population size has changed in relation to its original size expressed as a percentage (x100)
> cgr= 🔺N/N or (Nfinal - Ninitial) / N initial
How does a Growing population pyramid look
- Increasing offspring
- Wide base
- more births than deaths
🔺shape
How does a Stable Population graph look
- Rectangular shape
- about the same proportion of people each age category
- slightly more young than old
- death/birth even
What does a declining population graph look like
- Skinny narrow base
- Inverted triangle
- more older individuals that young
Species Interactions types (4)
> what are they
> how much energy is passed
Predator vs Prey or Producer vs Consumer are same thing just when prey is plant
Competition: Intraspecific (within same species) or interspecific (between diff)
Symbiosis: Parasitism (+/-) , Mutualism(+/+) or Commensalism (+/o) neutral - o
10% energy is passed as you go up foodchain
Defence Mechanisms types:
1- Cryptic colouration
2- Protective colouration
3- Mimicry colouration
1- Camouflage, helps organisms blend in to surroundings to avoid predators
2- Bright colours that give warning to predators of poisonous or bitter taste
3- Looking like a species that’s poisonous or harmful even if they aren’t
What type of interaction is mutalism
both benefit from relationship (+/+) between diff species
What type of interaction is commensalism
One organism benefits other is neutral/ unaffected (+/o)
What type of interaction is parasitism
(+/-) one organism benefits while other is negatively affected but not dead
Whats the defense mechanism cryptic colouration bc
camouflage that helps organisms blend into surroundings to survive
whats protective colouration
defense mechanics that looks bright and dangerous giving attackers watning of danger
whats mimicry defense mechanism
looking like another dangerous species to trick attackers even if ur safe
