just the entire thing in one deck Flashcards
What are the levels of organization
Organisms (their characteristics and adaptations)
Populations (groups of organisms of the same species)
Communities (different populations living in the same area and how they interact)
Ecosystems (all of the organisms in an area and its biotic and abiotic factors)
The Biosphere (all of Earth and global interactions)
what are producers?
(autotrophs) can make their own food, most often by photosynthesis (although there are chemoautotrophs in some food webs).
what are consumers
Consumers (heterotrophs) eat other organisms for food.
What is the difference between a food chain and web?
A food chain is a sequence of organisms through which nutrients and energy pass from one organism to another.
Food webs show many different and overlapping food chains.
What is a trophic level?
A trophic level indicates the number of steps in the food chain from the initial producers.
What is biomagnification/bioamplification?
the increasing concentration of a substance, such as a toxic chemical, in the tissues of organisms at successively higher levels in a food chain.
–> Some compounds (e.g. methylmercury, DDT, PCB’s) are stored in the fatty tissues of organisms, rather than being excreted. As a result, each level of the food chain consumes and stores the compound from its prey.
What is bioaccumulation?
the accumulation of pollutants or toxins in the tissues of an organism over its lifetime.
What is population density?
the number of individuals of the same species that occur per unit area or volume
What is the difference between crude density and ecological density?
crude density - population density within the total area of habitat
ecological density - population density within useable area
What are the different kinds of population distribution-+
clumped, uniform, random
what factors affect distribution patterns?
the distribution of resources (e.g. food and water) within a habitat
the interactions among members of a community (e.g. social interactions)
What are the different ways to measure population characteristics?
-use indirect indicators, e.g. tracks & droppings
- transect sampling – a path along which one counts occurrences of a population (e.g. plants or coral)
-quadrat sampling - define an area (e.g. 1 m2 or 1 km2) and count all organisms in that area, extrapolate to determine population sizes and densities (works best with stationary species)
-mark recapture method - individuals are captured, tagged (e.g. radio collar, band on leg) then released; time passes; individuals are captured again; proportion of marked to unmarked provides basis for estimating the size of population
What are factors of population growth?
death, birth, immigration, emigration
To determine whether a population is increasing or decreasing, calculate:
(births + immigration) - (deaths + emigration)
what are the types of populations?
open (regular) and closed (zoos, island)
What are the 2 different population growth models?
exponential growth: population growth under ideal conditions (no predators, unlimited resources)
–population is continually growing; no breeding season
–under these conditions, populations have high per capita growth rates (high biotic potential)
e.g. yeast, humans
logistic growth: growth increases exponentially as population is established, but levels off as the population nears its carrying capacity
carrying capacity = the max. # of organisms that can be sustained by the available resources over a period of time
What factors affect population as a whole?
Age when it is sexually mature
How often it reproduces
Number of offspring that survive to reproduce
Fecundity – the average number of offspring produced by a female member of a population over her lifetime
What are the types of survivorship curves (and describe them)
type I: species with a high survival rate of their young
-most of the individuals are expected to die only when old
e.g. humans, large mammals
type II: species in which individuals die at a constant rate from hunting, disease, etc.
e.g. chipmunks, bees, many reptiles and birds
type III: species in which most individuals die when young
many babies are born, but few survive very long
e.g. plants, most fish, sea turtles, many insects
What are r and k selection?
‘r’ refers to species whose population is well below the carrying capacity and can still grow exponentially with a rate (r)
‘K’ refers to populations that are almost at their carrying capacity (K)
c) ‘r’ and ‘K’ refer to different strategies that will ensure the survival of the species
What is the r strategy?
-unstable environment (e.g. after a flood)
-small size of organism
energy used to make each individual is low
-many offspring are produced
-early maturity
-short life expectancy (not always true, e.g. maple tree)
-each individual reproduces only once (not always true)
-organisms that use r strategy have type III survivorship
What is the k strategy?
-stable environment
-large size of organism
-energy used to make each individual is high
-few offspring are produced
-late maturity, prolonged parental care
-long life expectancy
-individuals can reproduce more than once
-organisms that use K strategy have type I and II survivorship
What is biotic potential, and limiting factors?
Biotic potential
the maximum reproductive capacity of a population under ideal conditions
Limiting factors
biotic or abiotic resources that limit growth, abundance, or distribution of a population of organisms in an ecosystem
What are the biotic limiting factors?
Intraspecific competition
individuals compete for resources with others of the SAME species
e.g. high density trees – lots of shade, little water, few nutrients per tree
Predation
from a predator viewpoint:
more prey/predator = more food
from a prey view point:
more prey/predator = less chance of being eaten
less prey/predator = more chance of being eaten
Allee Effect
reproduction fails to equal mortality due to low density
e.g. cannot find a mate
What is the minimum viable population size?
(the smallest number of individuals that ensures the pop. can persist for a determined amount of time)
What are the abiotic limiting factors?
temperature; regardless of how much food is available, a cold winter will cause a decline in an insect or plant population
e.g. DDT makes hawk egg shells thinner; regardless of how many hawks are in an area or how many good nest sites or how much food is available, the hawk population will decrease
What is interspecific competition?
2 or more species compete for the same resource
restricts population growth
e.g. competition for nesting space, prey, etc.
How is competition reduced?
competition is reduced by resource partitioning (species occupy slightly different niches)
e.g. competing bird species occupy different levels of a forest canopy
What are some adaptations of predators?
senses; e.g. eyesight; smells; echolocation
behaviour; e.g. stalking, sit & wait, organize a group
physical (morphological); e.g. claws, jaws
camouflage
What are some adaptations of prey?
physical (morphological); e.g. shells, spines, horns
camouflage
senses; e.g. hearing
behaviour; e.g. hiding, large groups
warning signals
toxins; e.g. blue-ringed octopus
mimicry (copy a poisonous animal) e.g. king snake
What are the different types of symbioses
a) mutualism; both species benefit
e.g. oxpecker and eland; insect pollinators and flowering plants
b) commensalism; one species benefits, one species is unaffected
e.g. algae on the back of a turtle; a clown fish and sea anenome
c) parasitism; one species benefits, one species is harmed
e.g. mosquito and human; tapeworm and human
What are the different types of population pyramid?
Rapid growth, Slow growth, Negative growth
What factors determine whether the world
population continues to grow, stabilizes, or crashes?
poverty, war, disease, population control measures (birth control), environmental impact,
What are the most important problems facing humankind?
climate change, loss of biodiversity, air polution, water polution, antibiotic resistance, land degredation
