unit 8 ecology Flashcards
ethology
how evolutionary processes shape inherited behaviors and the ways that animals respond to specific stimuli
behavior
an animals respond to the stimulus
- nature vs nuture (genetic and environmental factors)
- allow for survival and reproduction
- subject to natural selection
proximate cause
how a behavior occurs
1. what was the stimulus to cause the behavior?
ultimate cause
why a behavior occurs
- how does the behavior help the animal survive and reproduce
innate behavior
developmentally fixed
- no effect
- heredity, born, don’t need to learn
- scream, trying to avoid pain
learned behaviors
depend on environmental influence
- experiences do affect these behaviors
- high variation in a population
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
migration
a regular, long-distance change in location
○ Triggered by environmental cues
■ Sun’s position
■ Earth’s magnetic field
■ Celestial cues
signal and examples
a stimulus transmitted from one animal to another; animal communication
○ Examples: visual, auditory, tactile, electrical,chemical
Pheromones
chemicals emitted by members of a species that can affect other members of the same species
Stimulus response chains
when a response to a stimulus serves as the next stimulus for a behavior
● Seen in animal courtships
directed movements
movements towards or away from a stimulus
Kinesis
a change in the rate of movement or the frequency of turning movements in response to a stimulus; non directional
taxis
directional movement towards (positive) or away from (negative) a stimulus
imprinting
a long-lasting behavioral response to an individual
○ Happens during a sensitive period of development (usually very early in life)
■ Imprinting occurs on the first individual they encounter
● Example: ducks following their mothe
Spatial learning
establishing memories based upon the spatial structure of the animal’s surroundings
○ Some animals form a cognitive map or use
landmarks as environmental cues
■ Example: birds finding their hidden nests
Associative learning:
the ability to associate one environmental feature with another
○ Example: associating monarch butterflies with a foul taste
Social learning
learning through observations and imitations of the observed behaviors
○ Example: chimps breaking open oil palm nuts
Foraging
food obtaining behavior
■ Searching for, recognizing, and capturing food
items
● Animals better at foraging will be more
successful in finding food
Altruism
selfless behavior
■ Reduces the individual’s fitness, but increases
the fitness of the rest of the population
● Example: naked mole rat colonies have only
one reproducing female (queen), who will
only mate with a few males (kings). The other
nonreproductive members will sacrifice
themselves to protect their queen and kings.
Phototropism
a directional response that allows plants to grow towards (and in some cases away from) a source of light
Photoperiodism
allows plants to develop in response to day length
Ecosystem
the sum of all the organisms living in a given area and the abiotic factors they interact with
biotic vs abiotic
Biotic factors: living, or once living, components
of an environment
○ Abiotic factors: nonliving (physical and chemical
properties of the environment)
first two law of thermodynamics
- 1st law: energy can neither be created nor
destroyed, only transferred
■ Law of conservation of mass: chemical elements are continually recycled in the environment
○ 2nd law: exchanges of energy increase the entropy of the universe
A net gain in energy results in energy storage or
___ of an organism
growth
A net loss of energy results in loss of mass and
eventual ___ of an organism
death
Metabolic rate
the total amount of energy an animal uses in a unit of time
■ Oxygen is used in cellular respiration and CO2 is
produced as a by-product
○ An animal’s metabolic rate is related to its body
mass
■ Smaller organisms = higher metabolic rate
■ Larger organisms = lower metabolic rate
Endotherms
use thermal energy from metabolism to maintain body temperatures
ectotherms
use external sources (ie sun/shade or other organisms) to regulate their body temperature
energy ____ be recycled
cannot
MASS CAN BE RECYCLED
Primary producers
autotrophs use light energy to synthesize organic compounds
○ Plants, algae, photosynthetic plankton
■ Some organisms are chemosynthetic (vs photosynthetic) meaning they produce food using
the energy created by chemical reactions
● i.e. some bacteria and archaea organisms
Heterotrophs
rely on autotrophs because they cannot make their own food
If energy resources change…
so can the number and size of trophic levels (Increase energy, increase trophic levels/size; decrease energy,
decrease trophic levels/size)
■ A change at the producer level can affect the
number and size of the remaining trophic levels
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
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
Population
a group of individuals of the same species living in an area
Density
the number of individuals per unit area
○ Knowing a population’s density provides more
information about its relationship to the
resources it uses
clumped, uniform, random
Clumped: individuals gather in patches
○ Uniform: evenly spaced individuals in a
population
■ Can be due to territoriality
○ Random: unpredictable spacing; not common
The size of a population is affected by
Births/deaths
○ Immigration/emigration
describe the population curves
Type I curve: low death rate during early/middle
life and high death rate later in life
● Type II curve: constant death rate over the
lifespan of the organism
● Type III curve: high death rate early in life and
lower death rate for those that survive early life
Exponential growth model
a population living under ideal conditions (ie easy access to food, abundant food, free to reproduce, etc)
○ Population grows rapidly
logistic growth model
the per capita rate of increase approaches zero as the population size nears its carrying capacity
○ The density of individuals exceeds the system’s
resource availability
three variables affect life history
- When reproduction begins
- How often the organism can reproduce
- The number of offspring produced per
reproductive episode
K-selection (density-dependent selection)
selection for life history traits that are sensitive to
population density
○ Seen in high density populations that are close
to carrying capacity (K)
R-selection (density independent selection)
selection for life history traits that maximize
reproductive success
○ Seen in low density populations with little
competition
Density-dependent regulation:
as a population increases, factors can slow or stop growth by decreasing birth rate and increasing death rate
○ Competition, predation, toxic wastes, territoriality, disease, intrinsic factors (ie reproduction rates)
Density-independent regulation
factors that exert their influence on population size, but the birth/death rate of a population does not change
○ Weather, climate, natural disasters
community
a group of populations of different species living closely and capable of interacting
Habitat
a place of an ecosystem occupied by an organism
Ecological niche
the role and position a species has in its environment
fundamental niche vs realized niche
Fundamental niche: the niche potentially
occupied by the species if there were no limiting
factors (predators, competitors, etc)
○ Realized niche: the portion of the niche the species actually occupies
Competition
-/- relationship where individuals of different species compete for limited resources
○ Competitive exclusion principle: two species
competing for the same resource cannot coexist
permanently
■ The competitor with even a slightly better
advantage will eliminate the inferior competitor
Predation
+/- relationship where one species (predator) kills and eats the other species (prey)
■ Cryptic coloration: camouflage
■ Batesian mimicry: harmless species mimics a
harmful one
■ Mullerian mimicry: two or more bad-tasting
species resemble each other
symbiosis
when 2 or more species live in direct contact with one another
○ Parasitism: (+/-) when one organism (parasite)
derives nourishment from another (host)
○ Mutualism: (+/+) when both organisms benefit from
the relationship
○ Commensalism: (+/0) when one organism benefits
and the other is neither harmed nor benefited
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
species diversity (biodiversity)
the variety of different organisms within a community
○ Species richness: the number of different
species
○ Relative abundance: the number of individuals per species.
The main threats to biodiversity are:
Habitat loss
■ Invasive species
■ Overharvesting
■ Global change
Pathogens
disease causing organisms and viruses
○ Pathogens have the most effect on new habitats
or ecosystems with less biodiversity
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)
○ Include fungi and many prokaryotes
○ Important for recycling chemical elements
○ Population ecology
analyzes the factors that affect population size and how and why it changes over time
demography
the study of vital statistics of populations and how they change over time
herbivory
relationship where one organism eats part of a plant or alga
keystone species
not abundant, species rely on them bc their important ecological niches
disturbance
an event that changes a community by removing organisms from it or altering resource availability
- fires, droughts, human activities
ecological success
the gradual process by which the species composition of a community changes and develops over time after a disturbance
primary succession
changes on an new habitat that has not been colonized
secondary succession
changes that clears an existing community but leaves the soil intact
- drought, deforestation
examples of habitat loss
threat to biodiversity
- clear cutting, cattle gazing, farmland
invasive species
a nonnative species that can occupy a wide range of habitats and exclude nature species from these habitats
overharvesting
organisms are harvested faster than their population can rebound
- overfishing
- harvesting of ivory
global change
reduce the capacity of earth to sustain life
- air/water pollution
- CO2 emissions
- ocean acidification
