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 so 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 abundance (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