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Animal Behavior and Human Impact (what can we do (minimize habitat loss…
Animal Behavior and Human Impact
what is population ecology
explores how biotic and abiotic factors influence to density, distribution, and size of populations
population density, the number of individuals per unit area or volume
affected most by
birth/death rates
immigration/emigration
local densities can vary a lot, creating different patterns of dispersion
patterns of dispersion provide insight into environmental associations and social interactions of the population
uniform, individuals are evenly spaced
random, individuals are unpredictably spaced
clumped, individual are aggregated into patches
demographics
demography, the study of the vital statistics of a population and how they change over time
birth rate, fertility, fecundity
death rate, mortality
life table, provides a summary of age specific survival and reproductive rates of individuals in a population
cohort, a group of individuals of the same age
focus is mostly on females
population growth
survivorship curves, a plot of the proportion or numbers in a cohort still alive at each age
type 2, constant death rate over organism's life span
type 3, curve drops sharply at the start (high death rates young)but flatten out as death rates decline for those few individuals that survive the early die off period
type 1, flat at start (low death rate) during early and middle life and then drops steeply as death rates increases among older age groups
change in population growth
change in size = births + immigrants - deaths - emigrants
exponential growth, the growth of a population in an ideal, unlimited environment
abundant access to food
free to reproduce
carrying capacity, a limit to the number of individuals that can occupy a habitat due to lack of resources because of population increase
logistic growth rate, the per capita rate of population growth approaches zero as the population size approaches the carrying capacity
population dynamics and strategies
factors that affect population dynamics
trade-offs between survival and reproductive traits
number of offspring
investment in parental care
frequency of reproduction
life history, the traits that affect an organism's schedule of reproduction and survival
how often does the organism reproduce
how many offspring are produced per reproductive episode
when does reproduction begin
strategies used by organisms
K-selection, density-dependent selection
operates in population living at carrying capacity
competition is stronger
selection for life history traits that are sensitive to population density
r-selection, density-independent
selection for llife history traits that maximize reproductive success in uncrowded environments
happens in environments where population densities are well below carrying capacity
little competition
population dynamics, population tend to fluctuate in size from place to place or year to year
animal behavior and communication
behavior
innate behavior, an animal behavior that is developmentally fixed and under strong genetic control
are rooted in natural selection
are automatic as a result of the nervous and endocrine systems
exhibited in the same form by all individuals in a population despite internal or external differences during development
fixed action pattern, a sequence of unlearned acts directly linked to a specific stimulus
stimulus, automatic response
instincts, complex patterns of innate behavior in which an animal recognizes a stimulus and responds with a behavior that it carries out until all parts of it are finished
learned behavior, behaviors that are modified based on experiences or practice
imprinting, a long-lasting behavior formed at a specific stage in life in response to an individual or object
motivation, usually a response to an innate need
habituation, diminishing a response to a stimulus with repeated exposure
cognition, the process of knowing that may include awareness, reasoning, recollection, and judgement
why are behaviors important
behaviors increase survival and reproductive fitness
cooperative behavior increases the fitness of the individual and survival of the population
communication, the transmission and reception of signals between animals
signal behaviors or cues that produce changes in the behavior of other organisms
visual, audible, tactile, electrical, and chemical signals to indicate dominance, find food, and establish territory
biodiversity
three levels of biodiversity
species diversity, the number of species in an ecosystem or across the biosphere
endangered, in danger of extinction throughout all or most of its range
threatened, is likely to become endangered in the near future
ecosystem diversity, focuses on the interactions between population of different species in an ecosystem
genetic diversity, genetic variation within and between populations
threats to biodiversity
overharvesting
harvesting of wild organisms at rates exceeding the ability of their populations to rebound
has devastating effects on species with restricted habitats, large organisms with low reproductive rates
global change
includes alteration sin climate, atmospheric chemistry, and ecological systems that keep Earth habitable
toxins in the environment, synthetic compounds released by humans
climate change, a directional change in the global climate that lasts for 3 decades or more
agriculture, depletes soil nutrients
introduced species
no natural predators, parasites, or pathogens to limit the population
humans move intentionally or accidentally from the species' native locations to new geographic areas
non-native or exotic species, disrupt the new community, out compete
habitat loss
brought about by agriculture, urban development, forestry, mining, and pollution
fragmentation confines the organisms
biggest threat to biodiversity, where there is no alternative habitat or if a species is unable to move, habitat loss can mean extinction
what can we do
climate change
replace fossil fuels with renewable sources of power
reduce deforestation
improve human life while conserving biodiversity
sustainable development, economic development that meets the peoples' needs without limiting the ability of future generations to meet their needs
connect life science with social science, economics, and humanities
reassess personal values
minimize habitat loss
preserve biodiversity hotspots
nature reserves
movement corridors connect small clumps of the habitat that would otherwise end up isolated
zoned reserves
minimize the effects the human population has on biodiversity
reduce your ecological footprint
reduce waste
buy less
consider meat free meals
focus our conservation efforts to slow down the biodiversity crisis
declining population approach
focuses on threatened and endangered populations that show a downward trend
study the environmental factors that caused the decline in population
small population approach
study the processes that cause extinction sonce populations are greatly reduced
small populations are vulnerable to inbreeding and genetic drift leading to an extinction vortex