Transcript Unit XI: Ecology and Animal Behavior

Unit II: Ecology and Animal
Behavior
Ecological interactions affect how
organisms evolve, and evolutionary
change in turn affects ecological
relationships.
Ecology
Ecology
• the study of the relationships between organisms and their environment
+ two types of interactions
- biotic (living)
- abiotic (nonliving)
+ levels of study
- population, community, ecosystem, biosphere
• Population Ecology
+ population: group of individuals all of the same species living in
the same area
- describing abundance/distribution of populations
+ size (total number of individuals = N)
+ density (total number of individuals per area/volume)
+ dispersion (clumped, uniform, random)
Age Structure
Sweden- relatively stable population growth
Mexico- rapidly growing population
United States- relatively stable population growth
Survivorship Curves
Type I: most individuals die old
Type II: length of survivorship is random
Type III: most individuals die young
Population Growth
Biotic potential
• maximum growth rate of population under ideal conditions
Carrying Capacity (K)
• maximum number of individuals a population can sustain
+ limiting factors
- elements that prevent a population from attaining
its biotic potential
Density-dependent Factors
Density-dependent factor
•intensifies as population increases
+ reduce the population growth by
decreasing reproduction or by
increasing mortality
- parasites/disease, competition,
predation, stress
Density-independent Factors
Density-independent factor
occurs independently of population; unrelated to population
size
+ natural disasters and extremes of climate
Exponential Growth
J-shaped curve
Logistic Growth
Logistic Growth
• occurs when limiting
factors restrict the size
of the population to
the carrying capacity (K)
S-shaped/sigmoid curve
Community Ecology
Community Ecology
• looking at the interactions between populations
- positive (+), negative (-), or neutral (0)
+ types
- Competition
- Predation
- Symbiosis
Competition
Competition (-/-)
• interaction between individual organisms that use the
present in limited supply
niche: set of resources/conditions necessary for su
+ organism’s role/job in the community
- intraspecific / interspecific competition
+ same / different species
Predation
Predation (+/-)
• eating of live or freshly killed organisms
+ parasitism
- specialized predators do not actually kill prey (host)
+ Defense against Predators
cryptic coloration (camouflage)
aposematic coloration (warning coloration)
mimicry
+ Batesian (harmless species mimics harmful model)
+ Mullerian (harmful species resemble each other)
Symbiosis
Symbiosis
• close and long term association between organisms of two species
+ Mutualism (+/+)
- both organisms benefit from the interaction
+ mycorrhizae, lichens
+ Commensalism (+/0)
- one species benefits, but other is unaffected
+ remora-shark relationship
Community Composition and the
Question of Stability
Disturbances
• events, such as storms, fire, floods, droughts, overgrazing, etc.
+ damage community, remove organisms, alter resource availability
- communities are usually in a state of recovery
Ecological Succession
• change in the composition of species over time
+ climax community
- final successional stage of constant species composition
+ changes that induce succession
- substrate texture
- soil pH
- soil water potential
- light availability
- crowding
Primary Succession
• occurs on substrates that never previously
supported living things + Ex.) rock or lava
•
- lichens
•
- bacteria, protists, mosses
•
- insects, other arthropods
Secondary Succession
• begins in habitats where communities were
destroyed by disturbances
•
+ abandoned cropland
Ecosystems
Trophic Levels
• Primary producers
+ autotrophs (plants, protists, cyanobacteria,
Primary consumers
+ herbivores
• Secondary consumers
+ primary carnivores
• Tertiary consumers
+ secondary carnivores
• Detritivores
+ decomposers (fungi, bacteria,
earthworms, insects,
scavengers)
Pyramid of Energy
Ecological Efficiency
Ecological Efficiency
• proportion of energy
represented at one trophic level
that is transferred to the next
+ average efficiency=10%
- only 10% of productivity
is transferred to next level
- remaining 90% is
consumed by metabolism
Biogeochemical Cycles
Biogeochemical Cycles
• flow of essential elements from the environment to living things and
back to the environment
+ reservoirs
- major storage locations
+ assimilation
- processes through which element incorporates into
terrestrial plants and animals
+ release
- processes through which element returns to the environment
Hydrologic Cycle (water cycle)
Reservoirs: oceans, air, groundwater, glaciers
Assimilation: plants absorb from soil; animals eat/drink
Release: plants transpire; animals/plants decompose
Carbon Cycle
Reservoirs: atmosphere (CO2), fossil fuels, peat, cellulose
Assimilation: plants via photosynthesis; consumers
Release: respiration and decomposition; burn fossil fuels
Nitrogen Cycle
Reservoirs: atmosphere (N2); soil (ammonium, ammonia, nitrite, nitrate)
Assimilation: plants absorb from soil; animals consume plants/animals
Release: denitrifying and detrivorous bacteria; animal excretion
Phosphorous Cycle
Reservoirs: rocks
Assimilation: plants absorb from soil (phosphate); consumers
Release: decomposition; excretion in waste products
Biomes
Biome region of biosphere characteristized by vegetation and
adaptations of organisms inhabiting the environment
+ Tropical rain forest (high temp., heavy rainfall)
+ Savannahs (grassland with scattered trees)
- tropical, but receive less rainfall than rain
forest
+ Temperate grasslands (North American prairie)
- receive less water/lower temp. than savannahs
+ Temperate deciduous forests (warm summer/cold
winters)
Biomes
Cont’d
Deserts (hot and dry)
Taigas (coniferous forests)
- precipitation in the form of snow
Tundras)
- permafrost
Fresh water biomes (ponds, lakes, streams, rivers)
+ Marine biomes (estuaries, intertidal zones, continental
shelves,
•
coral reefs, pelagic oceans)
Animal Behavior
Ethology
• the study of animal behavior
• kinds of animal behavior
- Innate Behavior
+ instinct
+ fixed action patterns or FAP (Niko Tinbergen)
+ imprinting* (Konrad Lorenz)
- Learned Behavior
+ associative learning
- classical conditioning (Ivan Pavlov)
- operant conditioning (B.F. Skinner)
+ habituation
+ observational learning
+ insight
Animal Movement
Kinesis
• undirected change in speed of movement in response to stimulus
+ speed up in unfavorable; slow down in favorable
- light, touch, air temp., etc.
+ Avon bug in the bathroom tub
Taxis
• directed movement in response to stimulus
+ toward/away from stimulus
- phototaxis, chemotaxis
+ mosquitos and CO2
Migration
• long-distance, seasonal movement
Communication in Animals
Chemical
• pheromones
+ releaser pheromones cause immediate/specific behavioral changes
+ primer pheromones cause physiological changes
- marking your territory
Visual
• agonistic behavior
+ displays of aggression
• courtship behavior
+ announce participants as non-threatening/potential mates
Auditory
• sounds
+ whales, crickets, birds
Tactile
• touching
Social Behavior
Agonistic Behavior
• aggression/submission
+ competition for food, mates, territory
+ ritualized; reduces injury/energy
Dominance Hierarchies
• power and status relationships among groups
+ minimize fighting for food/mates
Territoriality
• possession/defense of territory
+ insures adequate food/space
Altruistic Behavior
• unselfish behavior that appears to reduce fitness
+ increases inclusive fitness