UNIT 8 TEST (54)
Overview
Ecology
The scientific study of the ==interactions between organisms and the enviornment==
Organismal ecology
How an organism’s structure, behavior, and physiology adapt to and complete challenges given from its enviornment.
Population
A group of individuals of the same species living in an area
Population Ecology
Analyzes factors that affects population size and how and why it changes
Community
A group of populations of different species in an area.
Community Ecology
Looks at how interactions between species (predation, competition) affect community structure and organization
Ecosystem
The community of organisms in an area and the physical factors with which those organisms interact.
Ecosystem Ecology
Energy flow and chemical cycling between organisms and the enviornment
Landscape Ecology
A variety of connected ecosystems
Biosphere
The sum of all the planet’s ecosystems and landscapes (global ecosystem)
Global Ecology
Looks at how the regional exchange of energy and materials influences the functioning and distribution of organisms across the biosphere.
8.1 Response to the Enviornment
Timing and coordination of biological mechanisms involved in growth, reproduction, and homeostasis depend on organisms responding to environmental cues.
How organisms respond to changes in their enviornment through behavioral and physiological mechanisms.
Physiological Responses
Changing the ==functioning== of the ==body==
Acclimation (dilating capillaries to release heat)
Proximate questions
Focus on the ==environmental== stimuli that trigger ==behavior==
Ultimate Questions
Focus on the ==evolutionary== significance of a ==behavior==
Morphological Responses
Changing the anatomy(structure) of the body
EX. Growing thick fur or change in fur color in winter
Behavioral Responses
Changing ==behavior== to adapt to the change
Moving to a more favorable location
Cooperative behavior
Agonistic behavior when threatened
Innate Behavior
is developmentally ==fixed==, regardless of the enviornment, and under strong ==genetic== ==influence== (agonistic behavior)
Learned behavior
is due to ==cognitive== development, change with ==experience== and (mother bear teaching her cubs how to hunt, pic berries, fish, and the best places to get the best food)
Learning
is the modification of behavior based on specific experiences
Maturation
loss of responsiveness to stimuli that convey ==little== or ==not== ==information==
Spatial Learning
The modification of behavior based on experience with the spatial structure of the enviornment, including the location of nest sites, hazards, food, and prospective mates
Associative Learning
The ability of many animals to associate one feature of the enviornment with another
classical conditioning
Arbitrary stim.
associated w reward or punishment
Pavlov’s Experiment
operant conditioning
“Trial and error learning”
Associated behavior w reward or punishment
Skinner Box
Cooperative Behavior
When an animal ==invests== resources in a ==common== ==interest== shared by other group members
Agonistic behavior
Any social behavior that involves ==fighting==, thus it is a contest involving ==threats==
3 divisions of behaviors: ==Threats==, @@aggression@@, and ==submission==
NO HARM IS DONE GENERALLY
Reconciliation Behavior
Often happens between conflicting individuals
Dominance Hierarchies
Ranking of individuals in a group
Alpha and Beta
Fixed Action Patterns (FAP)
A sequence of unlearned(innate), unchangeable behavioral acts, that once ==started== are ==carried== out to ==completion== that is ==triggered== by an external sensory stimulus
Imprinting
A type of behavior that includes both ==learning== and ==innate== components and is ==irreversible==
can only happen during the early development in an animals life (critical period)
EX. ==Konrad Lorenz imprinting himself onto incubated eggs==
Directed Movement
==Kinesis== is the change in ==activity rate== in response to stimuli.
EX. Isopods live best in moist conditions; move more in dry areas to increase likelihood of encountering a moist area
==Taxis== is a more or less ==automatic==, ==oriented== ==movement== toward or away from a ==stimulus==
Migration uses the sun (seasonal changes), stars, Earth’s magnetic field, ect.
Foraging behavior
Balance between ==benefits== and ==nutrition== adn ==cost== of finding food
Mate selection
Promiscuous- most common, no strong pair bonds
Monogamous- 1 male and 1 female
Polygamous- Individual of one sex matin with several of the other
Polygyny- 1 male lots of females
polyandry- 1 female lots of males
Organisms exchange information with one another in response to internal changes and external cues, which can change behavior
==Altruism==
Behavior that might ==decrease== ==individual== ==fitness==, but ==increase== the ==fitness== of ==others==
When one animal lowers their chances of survival to protect the greater cause
EX. Bees who devote their life to care for the queen
Signal
A behavior that causes a ==change in the behavior of another animal==
Communication occurs through various mechanisms
Communication
The transmission of reception of and response to signals
EX. Displays such as singing and howling
Information can be transmitted in other ways, such as chemical, tactile, and electrical
==Chemical== Communication
==Pheromones== are important in reproduction behavior
==Scents== are important in making territory or defense
==Electrical== Communication
Bumble bees use ==electrical signals== from ==flowers== to communicate with their hive because they flap their wings so fast.
Auditory Communication (vocalization)
==Drosophila== males produce a characteristic “==song==” by beating their wings, insects (innate, genetic)
Mating songs in birds (innate and learned)
Responses to info and communication are vital to natural selection and evolution
Natural selection favors innate and learned behaviors that increase survival and reproductive fitness. This is because they are actively learning new things to help them survive the changes presented to them.
==Inclusive fitness==
Evolutionary success depends on leaving behind the max number of copies of itself in the population which means the ==max number of offspring==
Kin Selection
Natural selection that favors ==altruistic== behavior by enhancing reproductive success of relative. Many altruistic animals are only altruistic to their relative so then their genes are more likely to survive. Therefore keeping the altruistic gene alive.
8.2 Energy Flow Through Ecosystems
The highly complex organization of living systems requires constant input of energy and the exchange of macromolecules
Organisms use energy to maintain organization, grow, and reproduce
Organisms use different strategies to regulate body temperature and metabolism
==Endotherms==
use thermal energy generated by ==metabolism== to maintain homeostasis.
Mammals like humans and birds
==Ectotherms==
Animals that don’t use metabolic heat production to maintain a constant body temperature
Their body temperature changes with the ==temperature of the enviornment==
They may regulate their temp. behaviorally by moving into the sun or shade or by aggregating with other individuals
Lizards and snakes
Metabolisms
is inefficient and produces heat
Metabolic heat keeps a stable body temperature
Metabolic rate
How quickly fuels (sugars) are broken down to keep the organism’s cells running
==BMR is used for Endotherms==
==SMR is used for Ectotherms==
It is given for the entire animal, meaning that it is given on a ==per-mass-basis.==
The smaller the animal, the higher the metabolic rate
EX. How much energy 1 gram of the animal’s tissue use er unit time
==BMR==
Baseline metabolic rate
Measured when the animal is in a thermoneutral enviornment or, where the organisms ==does not expend extra energy to maintain temperature==
==SMR==
will vary with temperature s==o any measurement is specific to the temperature at which its taken==
Storage
Energy is stored in chemical bonds
Some of your bodies reactions extract this energy and capture it as ATP which can be used to power other metabolic reactions
It can also be stored as glycogen or triglycerides
A net loss of energy results in loss of mass and ultimately, the death of an organism
Changes in energy availability can result in changes in population size
All living things need energy and nutrients to grow, maintain their bodies, and reproduce. Since in nature these resources are limited, there is competition for access to them. Therefore, they must allocate them into activities like growth, body maintenance and reproduction.
Life history
The ==pattern== of survival and reproduction events ==typical== for a member of the ==species== (==lifecycle==)
The patterns are often determines by natural selection and trade off of growth, survival, and reproduction
Semelparity
When members of ==one species reproduce only once but produce many.==
Iteroparity
Members of other species can ==reproduce multiple times but produce very few==
Fitness
The number of ==offspring== the organism leaves in the next generation
Changes in energy availability can result in disruption to an ecosystem
A change in energy resources such as sunlight can affect the number and size of the trophic levels
Producers rely on sunight to carry out photoynthesi
With limited sunlight (like in a canopy) that means that there are less producers which lead to less energy for consumers which leads to food chains getting even shorter and other species dying out.
Autotrophs capture energy from physical or chemical sources in the enviornment
Photosynthetic
organisms are autotrophs that often are primary producers and capture energy.
EX. Plants, algae, cyanobacteria
Chemosynthetic
Organisms that capture energy from small inorganic molecules present in their enviornment
Autotrophs
Can be found undersea in vent communities where no light can reach.
Heterotrophs capture energy present in carbon compounds compounds produced by other organisms
Heterotrophs cant capture light to chemical energy to make their own food out of carbon dioxide. They may metabolize carbohydrates, lipids and proteins as sources of energy
8.3 Population Ecology
Living systems are organized in a hierarchy of structural levels and interact.
Population Ecology
==the study of populations in relation to their enviornement==, including eviornmental influences on density and distribution, age structure, an dpopulation size.
Populations compromise individual organisms that interact with one another and with the enviornment in complex ways
Many adaptations in organisms are related to obtaining and using energy and matter in a particular enviornment
Population growth dynamics is the change in number of individuals in a population over time.
==dN/dT=B-D==
Without any contraints on reproduction the population can go into exponential growth.
Expontential growth
A populations per capita growth rate stays the same regardless of population size making the population grow faster as it gets larger.
j-shaped curve
==dN/dT=rmax N==
Logistical growth
a population's per capita growth rate gets smaller and smaller as population size approaches a maximum imposed by limited resources in the environment, known as the ==carrying capacity== ==(K)==
==s-shaped curve==
8.4 Effect of Density of Populations
Living systems are organized in a hierarchy of structural levels that interact
A population can produce a density of individuals that exceeds the systems’ resources
This is known as exponential growth, however, this can lead to limiting resources and will more likely cause high death rates compared to birth rates.
Dispersion
The pattern of spacing among individuals within the boundaries of a population
This allows for animals to spread out so all the resources aren’t being used by everyone in the same area
==UNIFORM==- ==territorial==
RANDOM- plants
CLUMPED- most common
As limits to growth due to density-dependent and density-independent factors are imposed, a logistic growth model generally ensues.
A logisitcal growth model introduces a carry capacity which limits the amount of organisms
Density dependent
Limiting factors cause a population’s per capita growth rate to change (usally drop) with increasing population density.
Competition
When a population reaches a high density, there are more individuals trying to use the same quantity of resources. This can lead to competition for food, water, shelter, mates, light, and other resources needed for survival and reproduction
Predation
Higher-density populations may attract predators who wouldn’t bother with a sparser population. When these predators eat individuals from the population, they decrease its numbers but may increase their own. This can produce interesting, cyclical patterns
Disease and parasites
Disease is more likely to break out and result in deaths when more individuals are living together in the same place. Parasites are also more likely to spread under these conditions.
Waste accumulation
High population densities can lead to the accumulation of harmful waste products that kill individuals or impair reproduction, reducing the population’s growth.
NEED FOR DECOMPOSERS INCREASES
Density-independent
Factors that affect per capital growth rate independent of population density
Disturbances
Fires
hurricances
tornados
8.5 Community Ecology
Communities and ecosystems change on the basis of interactions among populations and disruptions to the enviornment
The structure of a community is measured and described in terms of species composition and species diversity
This can be found using Simon’s Diversity Index
Simon’s Diversity Index
1- the sum of (n/N)^2
n- total number of organisms of a particular species
N- total number of organisms of ALL species
(PART/WHOLE)^2
Communities change over time depending on interactions between populations
Interspecific interactions (Symbiosis)
Interactions between 2 or more species
Competition (-/-)
Organisms of two species use the same limited resource and have a negative impact on each other. (leopard and lions)
Predation (+/-)
A member of one species, predator, eats all or part of the body of a member of another species, prey. (Lions and gazelles)
Herbivory (+/-)
A special case of predation in which the prey species is a plant (deer and plant)
Mutualism (+/+)
A long-term, close association between 2 species in which both partners benefit (bee and flower)
Commensalism (+/0)
A long-term, close association between 2 species in which one benefits and the other is unaffected (woodpecker and tree)
Parasitism (+/-)
A long-term, close association between 2 species in which one benefits and the other is harmed. (bacteria and an animal)
Relationships among interacting populations can be characterized by positive and negative effects and can be modeled
This can include predator/prey interactions, trophic cascades, and niche portioning
Trophic cascades
powerful indirect interactions that can control entire ecosystems
occurs when ==predators limit the density and/or behavior of their prey and thereby enhance survival of the next lower trophic level==
Niche Partitioning
niches are ecological roles or ways of life
How and where it lives.
==Partitioning separates different types of species and creates less direct competition==
animals living in different parts of a tree
Competitive Exclusion principle
==two species can't have exactly the same niche in a habitat and stably coexist.== That's because species with identical niches also have identical needs, which means they would compete for precisely the same resources.
Cooperation between organisms can result in enhanced movement of, or access to, matter and energy
This can be symbiosis between animals
8.6 occurring diversity ==among and between components within biological systems affects interactions with the enviornment==
Keystone species, producers, and essential abiotic and biotic factors contribute to maintaining the diversity of an ecosystem
Keystone species
A species that has ==disproportionately large effect on community structure relative to its biomass or abundanc==e (sea star)
Foundation species
Plays a unique, essential role in creating and defining a community. They act by ==modifying the enviornment== so that it can support the other organisms that form the community (kelp) (beaver)
Community Structure
The composition of a community, ==including the number of species in that community and their relative numbers.==
All of the patterns of interactions between these different species.
==Influenced by abiotic factors, species interactions, level of disturbance, and chance events.==
Species richness
The # of ==different species== in a particular community
30 species in 1 community < 300 species in another community
Affected by abiotic factors
Species diversity
A measure of ==community complexity==
A function of both the number of different species in the comunity (species richness) and their relative abundances (species evenness)
More species=higher species diversity
A forest community with 20 different kinds of trees would have greater species diversity than a forest community with only 5 kinds of trees (assuming that the tree species were even in abundance in both cases).
Chance events
suppose that a single seed blows into the dirt of a particular area. If it happens to take root, the species may establish itself and, after some period of time, become dominant (excluding similar species). If the seed fails to sprout, another similar species may instead be the lucky one to establish itself and become dominant.
8.7 Disruptions to Ecosystems
Going back to natural selection, if there is a favorable gene variation, it is hoped that it is passed down to each generation to give the organisms an advantage
These mutations are random and cannot be directed by specific environmental pressures
The intentional or unintentional introduction of invasive species can allow the species to exploit a new niche free of predators or competitors or outcompete other organisms for resources
Invasive species
species that have been introduced into areas outside their native range and can cause harm in their new area
It can alter community structure and throw off balance
Asian Carp
Human Impact accelerates change at local and global levels
Habitat change can happen due to humans. Deforestation is a big issue and happen because we tear down land to make room for new houses and roads
Biodiversity
The variety of organisms in an ecosystem
Renewable resources
Resources that are replaced as quickly as they are used
Nonrenewable resources
Resources that are limited in supply because they are used faster than can be replaced
Conservation
The study of the loss of Earth's biodiversity and the ways this loss can be prevented
Extinction
Process during which all members of a group of organisms die out
Endangered species
Species that has been identified as likely to become extinct
Biodiversity hotspot
A biogeographic region that contains high biodiversity and is also threatened with destruction
Climate change
Measurable long-term changes in Earth's climate