Unit 8 Ecology - AP Biology

includes topics from unit 8

be able to identify examples of:

• imprinting

• stimulus response chain

• fixed action pattern

• imprinting - a long-lasting behavioral response to an individual, happens during a sensitive period of development usually very early in life

  • example: ducks following their mother

• stimulus response chain - when a response to a stimulus serves as the next stimulus for a behavior

  • example: seen in animal courtships

• fixed action patterns (FAPs) - a sequence of unlearned acts directly linked to a stimulus, actions are unchangeable, carried out to completion, triggered by a sign stimulus (external cue) (

  • example: stickleback fish

define food web

linked food chains

define primary production

the amount of light energy that is converted to chemical energy

• primary producers set a “spending limit” for the entire ecosystems energy budget

• gross primary production (GPP): total primary production in an ecosystem

• new primary production (NPP): the GPP minus the energy used by the primary producers for respiration (Ra)

define secondary production

the amount of chemical energy in a consumer’s food that is converted to new biomass

• the transfer of energy between trophic levels is at around 10% efficiency

explain the significance of keystone species

not usually abundant, but other species in an ecosystem rely on them because of their important ecological niches

• keystone species, produces, and essential abiotic and biotic factors contribute to maintaining the diversity of the ecosystem

• if keystone species were to be removed from an ecosystem it would have a rippling effect (often ecosystems collapse)

define ethology

the study of how evolutionary processes shape inherited behaviors and the ways that animals respond to specific stimuli

define community

a group of populations or different species living closely and capable of interacting

define population

a group of individuals of the same species living in an area

• Population ecology - analyzes the factors that effect population size and how and why it changes overtime

define species

a group of organisms that can interbreed and produce fertile offspring under natural conditions, they share common characteristics and genetic similarities distinguishing them from other groups

transfer of energy between trophic levels

species can be grouped into trophic levels based upon their main food source of nutrition and energy

• energy cannot be recycled

• primary producers - (autotrophs) use light energy to synthesize organic compounds

• heterotrophs - rely on autotrophs because they cannot make their own food

  • primary consumers: herbivores

  • secondary consumers: carnivores that eat herbivores

  • tertiary consumers: carnivores that eat other carnivores

  • decomposers: get energy from detritus (nonliving organic material; leaves, wood, dead organisms)

• the trophic structures of a community are determined by the feeding relationships between organisms

• any changes to the availability of energy can disrupt ecosystems

explain phototropism

a directional response that allows plants to grow towards (and in some cases away from) a source of light

explain the WHY of higher vs lower organismal metabolic rates

metabolic rates - the total amount of energy an animal uses in a unit of time, can be measured in calories, heat loss or by amount of oxygen consumed, an animal’s metabolic rate is related to its body mass

• smaller organism = higher metabolic rate

• larger organisms = lower metabolic rate

WHY?

organisms use different strategies to regulate body temperatures

• endotherms = use thermal energy from metabolism to maintain body temperatures '

• ectotherms: use external sources to regulate their body temperature

differentiate between learned and innate behavior

• learned behaviors - depend on environmental influence

  • experience DO affect these behaviors

  • high variation in a population

• innate behaviors - developmentally fixed

  • hereditary, born behaviors, do not need to learn them; instinctive

  • experience during growth has no obvious effect

Note: while behaviors may lean one way more, many behaviors have both innate and learned components

be able to identify dispersion patterns given i information about an organism (dispersed, random, uniformed or clumped)

Dispersion - the pattern of spacing among individuals within a population

• clumped: individuals gather in patches

• uniform: evenly spaced individuals in population (can be due to territoriality)

• random: unpredictable spacing; not common

define ecological succession

the gradual process which species composition of a community changes and develops over time after a disturbance

• primary succession: a series of changes on an entirely new (previously lifeless) habitat that has been colonized

• secondary succession: a series of changes that clears an existing community, but leaves the soil intact

summarize the impacts of invasive species

a nonnative species that can occupy a wide range of habitats and competitively exclude native species from those habitats

be able to identify survivorship curves by description

• type I curve: low death rate during early/middle life and high death rate later in life (starts at top, goes across the top and ends at bottom)

• type II curve: constant death rate over the lifespan of the organism (diagonal line from top to bottom)

• type III curve: high death rate early in life and lower death rate from those that survive early life (starts at top, lowers to bottom, goes across the bottom)

be able to analyze experimental results and come to conclusions. (multiple examples of this on the test!)

be able to analyze experimental results to make conclusions about the “hierarchy of behaviors”

identify the effects of specific human activities on organisms

human activity is the strongest disturbance to an ecosystem

• the main threats to biodiversity are:

  • habitat loss

  • invasive species

  • overharvesting

  • global change

use the (+ / -) to describe the interspecific interactions, then describe them in detail:

• facilitation

• parasitism

• predation

• herbivory

• mutualism

• commensalism

• competition

• facilitation - (+/+ or 0/+) when one species has a positive effect on the survival and reproduction of another without intimate association of symbiosis, common in plant species

• parasitism - (+/-) when one organism (parasite) derives nourishment from another (host)

• predation - (+/- ) relationship where one species (predator) kills and eats the other species (prey), adaptations for both predators and prey have been refined by natural selection

• herbivory - (+/-) relationship where one organism eats part of a plant or alga

• mutualism - (+/+) when both organisms benefit from the relationship

• commensalism - (+/0) when one organism benefits and the other is neither harmed nor benefited

• competition - (-/-) relationship where individuals of different species compete for limited resources, competitive exclusion principle two species competing for the same resource cannot coexist permanently

describe the mechanisms of protection from herbivory in plants

• physical defenses: thorns, trichomes (small plant like hairs)

• chemical defenses: production of toxic or distasteful compounds

analyze a chart describing food sources among organisms in an ecosystem and create a representative food web