Exam 1 Study Set

Ecology!!!

1. What is ecology?

1. The study of interactions between organisms and their environments

Biotic Factors

Living things

All the organisms living in the area

Abiotic Factors

The non living components of an environment

ex. carbon, water, nitrogen, dirt etc.

What is an example of a biotic factor in a desert environment?

Lizard, snake, tarantula, cactus, bush, etc

What are the three main types of ecosystems? and give an example of each.

Terrestrial(desert, forest, cave), Freshwater(river, lake, pond), Marine(Kelp forest, coral reef, tidepool)

What are the components of a terrestrial ecosystem?

A terrestrial ecosystem must be on dryland

What components are shared between all types of ecosystems?

All ecosystems share abiotic components, but the biotic components differ

Define habitat.

the specific environment that an organism lives in, this includes both the biotic and abiotic factors of its surroundings.

Define niche.

An organisms niche refers to how an organism uses the biotic and abiotic components of its environment.

What are the trophic levels and how are they related to each other?

Define autotroph.

Organisms that produce their own food.

Define heterotroph.

Organisms that consume other organisms

Define Scavengers.

Organisms that feast on carcasses, like crows and vultures

Define Detritivores.

Organisms that consume decaying organic material, like earthworms and millipedes.

Define decomposer.

Organisms that secrete enzymes that digest molecules in organic material, like prokaryotes and fungi.

What are the two main ecosystem processes?

energy flow and chemical cycling

Do ecosystems need to recycle energy? Why?

Ecosystems dont need to recycle energy because the sun is an infinite source of energy which producers can use for photosynthesis and continue the flow.

How efficient are energy transfers?

Energy transfers are about 10% efficient

What do organisms require energy for?

Growth, maintenance, reproduction, and locomotion(in many species)

Define chemical cycle

Chemicals are available in a limited/finite amount in each ecosystem, chemicals are recycled within and between ecosystems. Living organisms acquire nutrients and release waste, at death, decomposers return the molecules to the environment.

Explain/Draw the steps of the water cycle

Explain/draw the carbon cycle

Explain/Draw the nitrogen cycle.

What would happen if you were to remove a species from an ecosystem?

The ecosystem won’t run optimally. It will either adapt or die

Define Interspecific relations.

Interactions between species

What are the types of interspecific interactions?

1. Competition(-/-), Mutalism(+/+), Predation(+/-), Herbivory(+/-), Parasitism(+/-), Commensalism(+/0)

Define symbiosis.

interaction between two different organisms living in close physical association.

What are the three types of symbiosis?

Mutualism(+/+), Parasitism(+/-), and Commensalism(+/0)

Define Competition

Organisms are competing over the same niche. Competition negatively impacts both organisms

Define competitive exclusion principle.

IF two species have an ecological niche that is too similar, the two species cannot coexist in the same place.

Define resource partitioning.

Organisms adapt so that their niches are similar but not 100% the same. For example, 5 birds that nest in the same tree will nest in different parts of the tree to avoid competition.

Define mutualism.

Both Species benefit from an interaction for example a certain fungus that grows on plant roots increases the amoun of water that the plant roots receive and in return the plant shares carbs with the fungus.

Define predation.

Interactions in which one species(the predator)

kills and eats another species(the prey). This interaction benefits the predator and negatively impacts the prey.

What are the adaptations that prey have evolved to avoid predators?

1. Mechanical Defense- structural in nature, porcupine quills
2. Chemical Defense- spray of skunk, toxins in plants
3. Cryptic Coloration- camouflage, a way to hide from predators, seahorse hiding in coral
4. Warning Coloration- brightly colored pattern that warns predators that the animal has an effective chemical defense, poison dart frogs


1. Mimicry- a form of defense in which one species looks like another species, can resemble twigs, leaves, bird droppings, predators, king snake mimics a coral snake

Define herbivory.

The consumption of plant parts or algae by an animal. This interaction negatively affects the plants/algae and benefits the animal. Ex. zebra eating grass

What are some defenses that plants have evolved to have against herbivores?

spines(mechanical defense), thorns(mechanical defense), and chemical toxins(chemical defense)

Define parasitism

A form of symbiosis where the animal lives in or on/outside of a host from which they obtain nutrients.

What are the two types of parasites?

Endoparasites(live inside of host), and ectoparasites(live outside of host).

Define commensalism.

A form of symbiosis where one organism benefits and the other is neither harmed nor benefits. Ex. birds nesting in trees, birds feeding off of insects that live on cattle.

What are the different types of community characteristics?

Biodiversity, Species Richness, Relative Abundance, Foundation Species, Keystone Species, and Invasive Species.

Define Biodiversity.

Measured by the number of different species in a particular area and their abundance.

Define Species Richness

The number of different species in the community. Diversity increases the productivity and stability of a community.

Define Relative Abundance.

The number of individuals in a species relative to the total number of individuals within an ecosystem.

Define Foundation Species.

base of a community, greatest influence on overall structure, usually have the highest relative abundance in an ecosystem, usually a primary producer/autotroph. ex. kelp, algae, plants, coral

Define keystone species.

Organism whose presence is key to maintaining biodiversity within an ecosystem.

Aids in upholding a community’s structure.

Define Invasive Species.

Nonnative organisms that threaten the balance of the habitat they live in.

How do invasive species get to nonnative habitats?

People introduce species to new environments.

Define disturbance.

An event that changes a community. The two types of disaturbances are Natural( Drought, fire, extreme weather) and Anthropogenic(Human caused-development, invasive species, habitat fragmentation, pollution, trawling, eutrophication).

draw a diagram depicting eutrophication

Define ecological succession.

The recolonization of disturbed areas. There are two types of ecological succession, primary and secondary.

Define Primary succession.

Begins with a pioneer species in an environment where life is not already present( lava islands, glaciers…etc)

Define Secondary succession.

Life was already present in the disturbed environment.

Define Population Ecology.

refers to how biotic and abiotic factors influence the abundance, dispersion, and age structure of populations.

Define Density.

The number of individuals per unit area or volume.

Example of high density- ants

Example of low density- tigers

Population size.

total number of individuals in a population.

Generally estimated.

Quadrat method- used for organisms that do not move(cecile) or are slow moving.(ex. plants, bacteria, soil invertabrates).

Mark-Recapture Method-used for estimating the population size of motile organisms(animals)

N=(sn)/x

x-number of marked animals captured the second sampling.

n=total number of animals captured in the second sampling

s-number of individuals marked/released in the first sampling

N-estimated population size

Animal marking methods-tag in fin/ear, small sharpie mark

Density and Population size are constantly changing due to…

Births, Deaths, Immigration, Emmigration, Competition, Disease, Predation, Territoriality, Toxic Waste.

Define Species Distribution/Dispersion.

Patterns of spacing among individuals within the boundaries of the population.

What are the 3 types of dispersion?

1. Clumped Dispersion-organisms clustered together within population, grouped either around resources of for protection.


1. Examples-flocks of birds, wolf packs, plants, mushrooms, insects.
2. Uniform Dispersion-Organisms are evenly spaces within population area due to territoriality or allelopathy(plants that secrete chemicals that prevent seed germination and the growth of other plants)


1. Example-Penguins
3. Random Dispersion-Organisms randomly dispersed within a population


1. Example-Plants with wind blown seeds, dandelions

\

What are the three types of survivorship curves?

Type I-low death rate/high survivorship-humans, elephants

Type II-limited parental care-rodents, birds

Type III-organisms with lots of offspring but little to no care-reptiles, fish, plants, invertabretes

Draw the three types of survivorship curves.

Describe the exponential population growth model

Describes population in an idealized, unlimited environment

Describe the Logistic Population Growth Model

Logistic model describes how a population grows more slowly as it nears its carrying capacity(limits growth)

Define K-selected species.

1. mature late
2. greater longevity/longer generation time
3. Increased parental care
4. fewer offspring
5. larger offspring


1. ex. trees, elephants

Define r-selected species

1. mature early
2. Lower longevity/shorter generation time
3. decreased parental care
4. more offspring
5. smaller offspring
6. ex. dandelion, jellyfish

(populations can recover faster)

Which type of species is more successful in nature?(k-selected or r-selected)

Both are successful in their own way

Define Semelparity

one time reproduction, ex. salmon, plants that produce one flower.

Define Iteroparity.

repeated reproduction, ex. mammals, reptiles, birds, fish, flowering plants.

Define evolution.

Descent with modification(Darwin’s Mechanism)

Define Macroevolution.

evolutionary change above the species level.

evolution of a new group of organisms following many speciation events(takes a really long time)

ex. new species.

Define Microevolution.

1. Evolution at its smallest scale
2. change in allele frequencies of a population over time
3. requires genetic variation


1. can happen in a single generation

Define alleles.

alternate forms of a gene

Define genotype.

A combination of alleles that dictates an organisms phenotype.

RR=homozygous dominant

Rr=heterozygous

rr=homozygous recessive

What are the sources of genetic variations?

1. Mutations


1. Happens when errors occur during DNA copying
2. change in the DNA or RNA of an organism
3. Forms new alleles
2. Altering gene number or position


1. Chromosomal changes-deletion, duplication, inversion, insertion, translocation
3. Rapid Reproduction increases mutation rates


1. more potential for mutations to occur
4. Sexual Reproduction


1. Combining genetic information from 2 different individuals produces genetic variation in the offspring

What are the Hardy Weinberg Equations?

p+q=1

p^2+2pq+q^2=1

What are the mechanisms of microevolution?

1. Natural Selection
2. Gene Flow
3. Genetic Drift

Define Natural selection.

The differential survival and reproduction of individuals within a population.

The primary mechanism of evolutionary change

Environment selects organisms that are most fit

Only mechanism that causes adaptive evolution, increases frequency of alleles that provide reproductive advantage

Acts more directly on phenotype.

Three types Disruptive, Directional, Stabilizing.

\

Define Disruptive selection and draw a graph

Conditions favor individuals at both extremes

ex. Birds with intermediate sized beaks are at a disadvantage for both seed types(unable to open large seeds, and to large to efficiently process small seeds5

Define Directional Selection and draw a graph

Acts to eliminate one extreme

often occurs in nature when environment changes

\

Define Stabilizing Selection and draw a graph

Acts to eliminate both extremes, makes intermediate more common

ex. in humans, infants with intermediate weight at birth have the highest survival rate.

Define gene flow and draw a diagram

Movement of individuals of gametes

Tends to reduce variation between populations

Define genetic drift.

change due to random chance events

magnitude of genetic drift is negatively related to population size

2 examples of genetic drift, Founder effect, and Bottleneck effect

Define the founder effect

A form of genetic drift when one of a few individuals migrate and become the founders of a new, isolated population. The alleles that they carry become a significant fraction of the new populations genetic endowments.

A serties of small populations that are isolated from one another may come to differ strongly as a result of genetic drift.

Ex. Island Species

(finches on galápagos islands)

\

Define the bottleneck effect.

(genetic drift) A drastic reduction in the number of individuals due to a random event can dramatically change the genetic makeup of a population

ex. Northern elephant seals

nearly hunted to extinction, as a result the species lost all of its genetic variation. The population number is now in the tens of thousands bu that genetic diversity is still low

Describe how soapberry bugs in Florida provide evidence for evolution.

Describe how the picture below provides evidence for evolution.

Comparative Anatomy- the comparison of the body structure of different species

Attests that evolution is a remodeling process in which ancestral structures become modified as they take on new functions.

Homology- The similarity in structures(but not function) due to descent from a common ancestor

ex. remodeling of the pattern of bones forming the forelimbs of mammals for different functions

Define Homology/Homologous structures

The similarity in structure(but not function) due to descent from a common ancestor

Define analogous structures.

Similarity in function due to common environmental selective pressures.

Define vestigial structures.

remnants of features that served important functions in an organism’s ancestors and now have only marginal, if any, importance.

ex. rear pelvis of whale

tail bone in humans

Describe how fossil records provide proof of evolution.

Shows descent with modification

Shows what evolutionary changes occurred in various groups of organisms

Shows how past organisms differed from present organisms

Define Speciation.

Process by which one species splits into two or more species

Intermediary between micro and macroevolution.

Species concepts: Phylogenetic, Morphological, Ecological, Biological.

Define phylogenetic as a species concept

If organisms DNA differs, then the organisms are different species

Define morphological as a species concept.

If two organisms look the same, then they are the same species.

Define ecological as a species concept.

If two organisms inhabit different niches, they are different species.

Define Biological as a species concept.

A group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but do not produce viable fertile offspring with members of other groups.

Cannot be applied to all species, doesn’t work with asexual reproducing organisms(bacteria).

What are the two types of speciation?

Sympatric- reproductive isolation

Allopatric- geographical isolation

Define Habitat isolation and give an example.

habitat preferences lower the probability of mating between individuals associated with differing habitats.

ex. flys eat different fruits and reproduce on different fruits. Over time this can lead to speciation.

Define Temporal Isolation and give an example.

Organisms mate in different seasons or are out at different times.

\

Define behavioral isolation and give an example.

Some behavior limits the interaction between two individuals.

\

Define Mechanical Isolation and give an example.

Reproductive structures aren’t compatible.

\

Define Gametic Isolation and give an example.

Gametic isolation happens when the egg and sperm are released but a zygote is not formed. The sperm can’t fertilize the eggs even if they come into contact.