Unit 4

What are the two fundamental questions related to Ecosystem Ecology?

- How do organisms facilitate the movement of matter (nutrients) and energy through different parts of an ecosystem? - How does the movement of nutrients and energy affect the abundance of organisms at DIFFERENT tropic levels?

Examples of terms associated with Consumption

- Predation (consuming entire animals) - Herbivory (consuming plants) - Parasitism (feeding on a host without killing it) -Parasitoidism (feeding on a host organism and killing it by consuming most of it

Only about __% of the food consumed is used to make more biomass.

10%

How long has ecology been a formal science?

125 years

Energy Pyramid

A diagram that shows the amount of energy that moves from one feeding level to another in a food web. (broad base = lots of energy for producers and narrow peak = little energy for high level consumers)

Values of each level on the Energy Pyramid

Apex Predator: .01% Third Level Consumer: .1% Second Level Consumer: 1% First Level Consumer: 10% Primary Producers: 100%

Levels of Ecological Study (largest to smallest)

Biosphere: global processes Ecosystem: energy flux and cycling of nutrients Community: interactions among populations Population: population dynamics; the unit of evolution Organism: survival and reproduction; the unit of natural selection

Mutualism

Both species benefit the other species by their presence by providing a resource the other lacks +/+ Facultative Mutualism: each species does better in the presence of the other than it would alone (e.g. anemone and clown fish). Obligate Mutualism: the species cannot live without the partner (e.g. coral and zooxanthellae)

What kinds of interactions might take place at the community level?

Competition Mutualism Consumption (Exploitation) Commensalism

Herbivory and predation are both examples of which type of ecological interaction? Mutualism Consumption Competition Commensalism

Consumption

Which of the following interactions is best illustrated by a food web? Competition Mutualism Consumption Commensalism

Consumption

List the first 4 Trophic Levels (bottom to top)

Decomposers (eat dead matter) Producers (organisms that can perform photosynthesis) Primary Consumers (organism that eat producers) Secondary Consumers (organism that eat primary consumers)

Factors that influence decisions on reproductive strategies

Environmental conditions Competition for resources Quality of resources Food abundance

Is a Food Chain or a Food Web a more accurate representation of trophic interactions?

Food Web

Insects have two main types of life cycles

Hemimetabolous Holometabolous

Which of the following is true because of the fact that only about 10% of food is used to make more biomass? High trophic level organisms are usually very common High trophic level organisms are usually uncommon Middle trophic level organisms are usually uncommon Middle trophic level organisms are usually very common

High trophic level organisms are usually uncommon

Example of Bottom-up

In many plants, having abundant water and nutrients makes the plant more resistant to insect herbivores and thus affects the availability of food for higher trophic levels.

Example of Top-down

In the northern Pacific Ocean the abundance of orcas (killer whales) has a strong impact on the number of sea otters, which in turn affects the number of sea urchins which in turn affects the abundance of kelp (large plant-like algae). If orcas are rare or absent, sea otters are common which keeps the population of sea urchins low and the kelp forms large 'forests' which are important for many other types of organisms. If orcas are abundant, sea otters become rare, sea urchins become common and the kelp forests become greatly reduced.

Commensalism

One species benefits from the interaction and the other derives neither benefit nor harm. +/0

Consumption (Exploitation)

One species is a resource (food) for the other. Thus, one species benefits from the interaction and the other is negatively impacted. +/-

The fields of Ecology (5)

Physiological Ecology Behavioral Ecology Population Ecology Community Ecology Ecosystem Ecology

At the end of the Larva stage in Holometabolous insects, there is a ______ stage in which the insect is ________ and the body is completely reorganized into the adult form.

Pupal Stage Dormant

Competition

Species are both using the same resources and thus each species negatively affects the other species -/-

True or False: Adding a single species to an ecosystem has the potential to change that ecosystem at multiple levels of organization

True

trophic cascade

When the change in population size, vigor, or behavior of one species can cause major changes in the species that it eats and/or the species that feed on it (alter the food web) - A trophic cascade is possible with either a top down or bottom up situation

Population

a group of individuals of the same species that live in the same place

Community

a group of species that occur together in the same place

In a Food Web, the size of the text and the arrows represents the....

amount of energy and biomass in each species and the amount transferred in each trophic interaction

Apex Consumer

any species that is in the highest tropic level in a community

Organisms can overcome environmental variation through _______

behavior

In a Food Web, do the organisms at the top or bottom have a greater biomass?

bottom - lose energy as you go up

A scientists adds fertilizer to the soil in a grassland and measures a change in the insects feeding on the plants. This change is an example of which of the following? mutualism competition bottom up control top down control an energy pyramid

bottom up control

The study of species diversity and the role of interactions among species in influencing diversity is known as ___. ecosystem ecology population ecology behavioral ecology community ecology

community ecology

Food Chain

conceptual device that shows which organisms consume others - they are NOT accurate representations of the complexity of real communities

Ecosystem Ecology

concerned with two fundamental questions questions having to do with interaction of biotic (living) and abiotic (nonliving) components of organism -NOT concerned with understanding the number of species or abundance or individuals of a species

Levels of organization refers to the....

different levels at which biology can be studied examples: molecule, cell, organ, population, community

Holometabolous Insect Life Cycle

egg -> caterpillar (larva) -> caterpillar beginning to pupate -> chrysalis (pupa) -> butterfly emerging from chrysalis -> adult butterfly

Hemimetabolous Insect Life Cycle

egg -> first instar nymph -> second instar nymph -> third instar nymph -> fourth instar nymph -> fifth instar nymph -> adult bug

Shape of the female and male bean beetles

female: long a thin male: short and fat

Trophic Levels can be organized into a....

food chain

Why is a food web a more accurate representation of a community than a food chain? most organisms are specialists and have only one food source food webs incorporate competition and mutualism unlike food chains food chains don't tell you at what trophic level each species occurs food webs can show that species can occur at multiple trophic levels food webs just look better

food webs can show that species can occur at multiple trophic levels

Holometabolous Insects

have a juvenile stage that is completely different from the adult stage - butterflies, flies, bees, beetles

Hemimetabolous Insects

have a juvenile stage that is similar to the adult stage - grasshoppers, crickets, cockroaches

Aspirator

hollow instrument used to withdraw the beetles

Which organism is the most important group of herbivores (primary consumer) in terrestrial ecosystems?

insects

Insect herbivores differ from mammalian herbivores in which of the following ways? insects never harm the plants they eat insects only eat plants that are distasteful to humans each insect species eats many different plant species insects tend to be more specialized in the plants they eat

insects tend to be more specialized in the plants they eat

An insect that is holometabolous is distinguished by which of the following? it can fly it has six legs it has a pupal stage young are called nymphs

it has a pupal stage

Top-down

it is the highest trophic levels that strongly affect the abundance of other species

What is the juvenile stage called in Holometabolous Insects?

larva - the larva are mostly not very mobile and thus plant choice is crucial

Oviposition

laying of eggs

Most energy and matter that is eaten by an organism is either............ or used in the.........

lost as waste -or used in the- maintenance of the organism (e.g. used in cellular respiration to generate ATP for cellular functions)

What is the juvenile stage called in Hemimetabolous Insects?

nymph - it is essentially a miniature version of the adult without wings

A community is a group of __________________ of different species that all occur in the same area. populations ecosystems offspring genomes

populations

A species interaction in which on species benefits and another species does worse than it would if it was alone is known as ___. predation mutualism photosynthesis production

predation

Organisms that feed upon plants are known as ___. producers primary consumers secondary consumers ovipositors

primary consumers

Food Web

shows the trophic relationships among species in a community by drawing arrows between them

Community Ecology is fundamentally concerned with understanding ________ ________

species diversity

Behavioral Ecology

studies how individuals interact with their environment through behavior example: social interactions such as mating behavior among members of a species

Physiological Ecology

studies how the physiologies of individual organisms interact with the environment example: how a cactus allows itself to conserve water

Population Ecology

studies of how the environment affects characteristics (size, density, distribution) of a population - is concerned with understanding why species are common/rare, why they might have many/few offspring, why a population might be growing/shrinking

Community Ecology

study of interactions among species and of the factors that influence the number of species occurring in a community - why do some communities have a large amount of species while others have a small amount?

Bottom-up

the health and vigor of the producers has a strong impact on the rest of community

Ecology

the study of interactions between organisms and their environment

Effects of organisms on the structure of communities through food webs can be described as _________ or _________

top-down or bottom-up

The different fields (Physiological, Behavioral...) of ecology demonstrate the....

wide range of interactions among organisms and their environments