Bio100 final Flashcards
(36 cards)
population
a group of the same species in an area
community
different species in an area
ecosystem
interactions between living (biotic) and non living (abiotic, soil, temp, precipitation) in an area
biosphere
parts of the earth occupied by living organisms
Population density
how many people in an area (lots= high density)
population dispersal patterns
uniform: territorial organisms, resources are evenly distributed random: depending on scale, no pattern clumped: clumped resources, social interactions
how do you get zero population growth
of birth and # of death rates are equal
what factors limit population size
- # of women that can reproduce
- resources
- density dependent factors
- density independent factors
growth patterns: exponential
unlimited resources, high birth rate
growth patterns: logistic
limited resources. variable K is the carrying capacity, # of species that can live in an area
growth patterns: boom and bust cycles
exponential growth and then crash of a population
density dependent factors affection population size
conditions whose growth limiting effects increase as population grows (food, space, water, spread of disease)
density independent factors affecting population size
factors that apply pressure that are unrelated to population density (natural disasters, disease entering an area)
K-selected species vs. R-selected species (characteristics)
K- selected: fewer offspring influenced by density dependent factors, logistical growth pattern - slow development - low reproductive rates - constant population size R-selected: "rate" high birth rate - rapid development - high reproductive rate
Human population trends
demographic transition, more developed country, population skyrockets, birthrate decreases
relationships among organisms
mutualistic: host and visitor benefit commensalism: host is unaffected, visitor benefits predation: prey or predator effect the other’s population - mimicry: act like their prey, predator avoidance parasitism: host is harmed, visitor benefits - endo: lives inside host - ecto: attaches on the outside of the host competition: when two or more species compete for the same limited resource (water/food) - niche: all the resources a species exploits for its survival, growth and reproduction - competitive exclusion: one winner, only one species can live there - resource partitioning: both species can survive (niche partitioning), increases diversity
which 3 relationships among organisms are symbiotic
mutualism, commensalism, and parasitism
Successional stages in communities: primary vs. secondary stages
primary: “virgin” land, unoccupied by plants, occurs from volcanos and glaciers melting, no soil. pioneer community grows first, don’t require lots of soil, lichen releases acidic waste secondary: plant community destroyed by a disaster, time for plants to recolonize
energy flow through a food chain vs. a food web
food chain: producers (plants), primary consumers (snails, plant predators), secondary consumers (fish), tertiary consumers (sharks), 10% of energy transferred between trophic levels Food web: energy flows from producers and so on
Keystone species
a species whose removal dramatically affects all the other organisms in that community
Water Cycle
evaporation, precipitation, infiltration/runoff, plants/animals, nutrients, transpiration: water into atmosphere from plants - water on earth: salt water 97.5%, fresh 2.5%
what is desertification and how does it happen
land becomes desert -water loss is greater than replacement - climate variations - deforestation - urbanization and agriculture - diversion of freshwater sources
Biomes: temperature, precipitation, species
Biomes: major ecosystem types that occupy different geographical areas and have distinct climates, plant and animal species temperature: depends on the distance from the sun precipitation: wind currents, dry air vs. wet air in 60 degrees north and south, we are at 30 degrees so we have cool winters and hot summers, further towards the poles have mild summers and below freezing winters
rain shadow effect
dry area on the downside of a mountain. moisture from the ocean loses moisture when trying to go over a mountain range causing precipitation on that side