Lecture 37 - Our Global Environment/Ecology/Biosphere I Flashcards
What is ecology?
scientific study of interactions between organisms + the environment
What are the 6 levels of ecology?
- global
- landscape
- ecosystem
- community
- population
- organismal
What is the biosphere?
- global ecosystem
- sum of all the planet’s ecosystems
What is global ecology?
-examines influence of energy + materials on organisms across the biosphere
What is a landscape?
-mosaic of connected ecosystems
What is landscape?
-mosaic of connected ecosystems
What is landscape ecology?
-focuses on exchanges of energy, materials + organisms across multiple ecosystems
What is an ecosystem?
-community of organisms in an area + physical features they interact with
What is ecosystem ecology?
-emphasizes energy flow + chemical cycling among various biotic + abiotic components
What is a community?
group of populations of different species in an area
What is community ecology?
-examines effect of interspecific interactions on community structure and organization
What is a population?
-group of individuals of same species living in an area
What is population ecology?
-focuses on factors affecting population size over time
What is organismal ecology?
-studies how an organism’s structure, physiology + behavior meet environmental challenges
What are abiotic factors?
-temperature, light, water, nutrients
What are biotic factors?
-other organisms that are part of an individual’s environment
What are biomes? What are they characterized by?
- major life zones
- characterized by vegetation type (terrestrial) or physical environment (aquatic)
What are 2 types of climate?
- macro
- micro
What is dispersal?
-movement of individuals or gametes away from centers of high population density or area of origin
The ability for a species to disperse or transplant often depends upon _____
abiotic factors
What are 5 biotic factors that affect distribution of organisms?
- predation
- herbivory
- competition
- mutualism
- parasitism
similar characteristics can arise in distant biomes through _______
convergent evolution
EX: cacti in N. America and euphorbs in African deserts
Population growth is ____ under ____ conditions
exponential
idealized
What is r
growth rate
Why is exponential population growth unrealistic?
-population will reach carrying capacity (K)
What is carrying capacity? (K)
maximum amount the environment can support
6 factors that are affected by density
- competition for resources
- disease
- predation
- territoriality
- intrinsic
- toxic wastes
As population becomes more ______ this leads to movement out or _____
- dense
- emigration
What are metapopulations
-groups of populations linked by immigration and emigration
What are 3 main variables of life history?
- age at which reproduction begins
- how often the organism reproduces
- how many offspring are produced per reproductive episode
What is semelparity?
“big-bang” reproduction
-reproduce once and die
What is iteroparity?
- repeated reproduction
- produce offspring repeatedly
Which kind of environments favor semelparity?
-variable/unpredictable environments
Which environments favor iteroparity?
dependable environments
What is k-selection?
- density dependent selection
- selects for life history traits that are sensitive to population density
What is r-selection?
- density-independent selection
- selects for life history traits that maximize reproduction
When did human population start growing exponentially?
1650
When did growth of the human population slow?
1960s
Different populations in the world go through _____ at different times
demographic transition
What is demographic transition?
high birth/death rate to low birth/death rate
What is a major factor associated with demographic transition?
-improved healthcare/education for women
What figure can you use to tell what stage of the demographic transition that a country is in?
age structure pyramids
What is an ecological footprint?
summarizes aggregate land and water area needed to sustain the people of a nation
