exam 2 Flashcards
population
group of species in same area competing for resources
population ecology
how population interacts with environmental factors
exponential growth
nothing to stop it – population grows, offspring produces more offspring, etc. j-shaped growth curve. ex. rabbits
logistic growth
grows until carrying capacity – then slows down. s-shaped curve. ex. wolves
density-dependent factors
issues impacted by population density (food shortage)
density-independent factors
issues to a population not impacted by density (floods, fires)
r-selected species
lot of offspring, 1 or 2 survive. little parental care (ex. insects)
k-selected species
few offspring, lot of parental care (ex. elephants)
births in population
Impacted by species, food availability, stress on species
Death in species
Varies by species, environmental factors
Immigration
Moving from one population to another
Emigration
Leave population, move to new area. Helps to avoid competition
Intraspecific interactions
Species members compete for resources:
Population crash, Strong survive
Individuals also survive by taking territory, out-conquering
Stress related diseases—overcrowding—faster disease spread
Interspecific competition
Predator-prey: keeps population in check
mutualism – both species benefit.
prey/predator growth
lot of prey – predator grows (more resources). eventually, food for prey runs out – pred. growth.
prey population crash = predator pop. crash
desert locust
stressed, leave desert, grow wings, swarm an area. one swarm – 50-100b locusts. can consume as much food in one day to feed 500k people for a year
human population/growth rate
7.7 billion – 1.09%
rate of growth
b + i - d - e
demographics
births, deaths, distribution, pop. size
crude birth rate
births per year per 1k people
total fertility rate
number of kids born to average woman during life
crude death rate
deaths per 1k persons/year
natural increase
crude death rate - crude birth rate
life expectancy
average death age
rapidly growing pop.
population is wide at bottom, decreases as it goes up. lot of young people who will grow into reproductive age – have kids – no decrease in fertility rate
stable pop.
same number of people in each age group. roughly even graph top to bottom
declining pop.
more old people than young people. big middle section of graph, smaller top and bottom
I = PAT
environmental impact = population * affluence * tech
enviro health
external disease-causing factors + elements of natural, social, cultural, tech worlds
pathogens
disease causing organisms
emergent diseases
diseases not known or absent last 20 years
pesticide resistance
overuse of few drugs and pesticides – marla
