Final Exam

Ecology is the study of

relationships between organisms (ecological pyramids) and how organisms interact with their environment

Ecological Niche

A specific role of a species within an ecosystem, including its use of resources, and relationships with other species.

Symbiosis

A relationship in which two different organisms live in close association with each other

Mutualism

A relationship between two species in which both species benefit

Commensalism

A relationship between two organisms in which one organism benefits and the other is unaffected

Parasitism

A relationship between two organisms of different species where one benefits and the other is harmed

Predation

An interaction in which one organism captures and feeds on another organism

Competition

the struggle between organisms to survive in a habitat with limited resources

Producers (autotrophs) vs Consumers (heterotrophs)

produce energy and provide basis for ecosystem vs have to rely indirectly or directly on producers for energy

Decomposers

Organisms that break down the dead remains of other organisms

Co-evolution

Process by which two species evolve in response to changes in each other

Succession

(ecology) the gradual and orderly process of change in an ecosystem brought about by the progressive replacement of one community by another until a stable climax is established

Primary succession

An ecological succession that begins in an area where no biotic community previously existed

Secondary succession

Succession following a disturbance that destroys a community without destroying the soil

The Cell

Basic unit of life

Prokaryotes vs. Eukaryotes

- Prokaryotes have no nucleus or membrane bound organelles
- Eukaryotes have a nucleus and membrane bound organelles
- Both can reproduce and respond to the environment

Photosynthesis

process by which plants and some other organisms use light energy to convert water and carbon dioxide into oxygen and high-energy carbohydrates such as sugars and starches

Cellular respiration

Process that releases energy by breaking down glucose and other food molecules in the presence of oxygen

Anaerobic respiration

Respiration in the absence of oxygen. This produces lactic acid.
• Yields less energy
• Bacteria produce food
• carbohydrates only partially broken down

Chemosynthesis

Process by which some organisms, such as certain bacteria, use chemical energy to produce carbohydrates.
• In extreme environments, e.g., ocean
• Creates sugars from inorganic chemicals, CO2 and O2
• Used by bacteria in ecosystems with no light
• Example: bacteria take in CO2, O2 , and H2S --- produce carbohydrates, sulfur, and H2O
• Energy is provided by conversion of H2S to S
• Carbohydrates are used for the growth of all organisms in ecosystem

Biological systematics

- employs both classification and knowledge of phylogeny to discover the relationships of all the amazing life forms on earth.
- provides meaningful groupings of organisms based on evolutionary relationships

Taxonomy

classification of organisms through description, identification, and naming

Hierarchy of biological classification

has eight major taxonomic ranks which encompass all known life.
Lazy drunk King Philip came over for green soup

Domains of Life

1. Eubacteria
2. Archaea
3. Eukaryota

Eukaryota

domain of organisms that contain nuclei, includes animals, plants, fungi, and protists

Phylogeny

The evolutionary history of a species or group of related species

Evolution

- Change in a kind of organism over time;
- process by which modern organisms have descended from ancient organisms;
- the continuous genetic adaptation of organisms to their environment through time

Carolus Linnaeus

(1707-1778) Founder of taxonomy, the branch of biology concerned with naming and classifying organisms. Developed two part system of naming organisms.

Lamarck

French naturalist who proposed that evolution resulted from the inheritance of acquired characteristics (1744-1829)

Nicholas Steno

First to recognize fossils were remains of organisms. Father of stratigraphy.

Uniformitarianism

· The processes at work today are the same as those that have been operating throughout the entire history of Earth.

Fossil

The preserved remains or traces of an organism that lived in the past

What can fossils show?

Organisms have appeared and disappeared, and have changed over time
Extinction of species
Transitional forms reveal links between groups:
Reveals ancient climate & environmental conditions
Indicates development of life from simple to complex
Indicates life began in water

Relative Dating

Method of determining the age of a fossil by comparing its placement with that of fossils in other layers of rock

Absolute Dating

A technique used to determine the actual age of a fossil.
(Carbon-14, Uranium-238, Potassium-40)
Measure the proportion of an isotope relative to its more stable form (half-life)

Half-life

length of time required for half of the radioactive atoms in a sample to decay

Darwin's Theory

Organisms born with the best adaptations survive and pass on their traits to offspring. Organisms without these adaptations die and do not reproduce. Over time, the population changes as more organisms inherit the adaptation.

Natural Selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.

A process by which favorable traits become more common and unfavorable traits become less common in successive generations of a population

Survival of the Fittest

Process by which individuals that are better suited to their environment survive and reproduce most successfully; also called natural selection

Darwin's Four Theories of Evolution

1. Evolution has occurred:
· Species are not unchanging entities but evolve over time.
· All species derive from very different species living in the past.
· This theory was not entirely new, but Darwin provided convincing evidence for it.


2. The primary cause of evolutionary change is natural selection:
Species change over time because bearers of different traits have different probabilities of contributing offspring to the next generation.

3. Splitting of single species into two or more species has occurred:
· Darwin postulated that all life originated with one or a few species.
· Because many species exist today, there must have been a process whereby one species can split into at least two species.
Conclusion: All species share common ancestors.

4. Evolutionary change is gradual:
Evolution occurs by the gradual transformation of populations over long periods of time (hundreds to millions of years) rather than by a species changing nearly instantaneously into something different.

Conditions for natural selection

· Many more individuals are born than survive (COMPETITION).
· Individuals vary in traits directly related to their ability to survive and reproduce (VARIATION).
· These advantageous traits are passed on to offspring (HERITABILITY).
· This process is repeated generation after generation over long periods of time (ITERATION).

Mutation (evolution)

permanent inheritable change in genetic material within cells

Directional selection

refers to natural selection that favors the survival of individual organisms at one extreme end of the range of variation within a population

Stabilizing selection

refers to selection that favors traits that fall somewhere in the middle of the range of variation within a population.

Disruptive selection

refers to situations in which individuals with genetic traits that fall at the extreme ends of the range are more likely to survive than individuals with average traits; occurs when a population confronts contrasting environments.

Mendel

Father of Genetics; responsible of the Law of Inheritance

Species

A group of similar organisms that can breed and produce fertile offspring.

Speciation

the origin of a new species from two or more individuals of a pre-existing one

Allopatric speciation

The formation of new species in populations that are geographically isolated from one another.

Sympatric speciation

The formation of a new species as a result of a genetic change that produces a reproductive barrier between the changed population (mutants) and the parent population. No geographic barrier is present.

Biodiversity

Variety of living things in all forms, combinations, and organization
• Ecological diversity (Landscape biodiversity)
• Species diversity (Community biodiversity)
• Genetic diversity (Population)

Endemic Species

Species that are found only in specific environments or restricted localities. Such species are especially vulnerable to extinction.

Landscapes with many unique species have

a high amount of endemism.

Product of local disturbance

Mosaic of patches undergoing different stages of succession.
•Plant and animal species vary from patch to patch;
depending on the kind of disturbance and time since it occurred

Species richness

total number of species in an area

Species evenness

the relative abundance of species in a community

Changes in species evenness indicate

changes in the environment.

Loss of species richness indicates

• that species are disappearing from an area
• threat to the survival of those species

Structural complexity

the three-dimensional distribution of species and biological features

Captive breeding programs

Raising and breeding organisms under controlled conditions, such as zoos or aquariums, to restore genetic diversity.

Inbreeding

• Mating between closely related individuals
• Increases chance of genetic disease and reproductive failure

Outbreeding

Mating of organisms that are not closely related; this is a major mechanism of maintaining variation within a species; Maximizes genetic diversity

Remaining populations usually lack

genetic variation needed for long-term evolutionary change, likelihood of adverse effects of genetic defects increases (even greater risk)

Biodiversity hotspots

Relatively small areas of land that contain an exceptional number of endemic species and are threatened by human activities

What makes biodiversity hotspots hot?

Unique habitats, topographic diversity, isolation

Extinction

A term that typically describes a species that no longer has any known living individuals.

Examples of human activities that increase the extinction rate are

1. Habitat loss/destruction - most important
2. Habitat fragmentation
3. Overharvesting
4. Non-native invasive species
5. Pollution (e.g., air, water)
6. Altered patterns of disturbance
7. Climate change

What is the single-greatest threat to biodiversity?

Habitat Loss

Habitat fragmentation

Breakup of a habitat into smaller pieces, usually as a result of human activities. Habitats are divided into small disconnected habitats vulnerable to catastrophic events.

Populations in habitat patches are

smaller and more vulnerable to local extinction

Characteristics of small habitat patches:

1. Life of organisms is disrupted
2. Tree seeds blow on unsuited land
3. Animal food and shelter may be separated
4. Larger animals may need breeding areas larger than the fragment
5. Migration pathways might be blocked (roads, damns)
6. Traffic sound disturbs wildlife

Overharvesting

removal of a species at a rate that the species cannot replenish in time (underpopulated or depleted)

Species vulnerable to overharvesting

• large bodies, slow growth rates, and flocking behavior
• sources of human food or medicine
• prized by collectors such as exotic tropical birds and trophy animals

Non-native invasive species

Species that are not native to a particular area and since they have no predators or competitors can become overpopulated very quickly.

Altered patterns of disturbance

• Ecosystems have natural cycles of disturbance/periodic fires or windfalls from hurricanes
• many species depend upon these regular disturbances to reproduce and grow

Changes of frequency and intensity
-Floods
-Fire

Change species composition

Conservation strategies

1. Hunting and fishing laws
2. Preserves and Protected Areas
3. The Endangered Species Act (ESA)
4. Recovery plans
5. Reintroductions
6. Minimum viable population
7. Private land and critical habitat
8. Reauthorization of the ESA
9. International wildlife treaties

Conservation

Protecting and preserving natural resources and the environment

Preserves and protected areas

-Behave as islands
-Depend on principles of island biogeography

Size
-Larger preserves support more species

Connectivity
-Migration corridors

Distance from other preserves

Buffers
-Protect from human influence/disturbance

Population viability

Probability of extinction in a given number of years.

Affected by:
• Availability and quality of habitat
• Size of population
• Disease/predators

Umbrella species

species whose being protected under the Endangered Species Act leads to the preservation of its habitat and all of the other organisms in its community

A good umbrella species candidate might be

• Top carnivores, require large territories and help ensure the diversity of lower trophic levels (Jaguar, Mexico & Central America)
• freshwater mussels that are particularly sensitive to pollution or other environmental changes are also effective umbrella species.

Endangered Species Act

(1973) identifies threatened and endangered species in the U.S., and puts their protection ahead of economic considerations
• Endangered: in imminent danger of extinction

• Threatened: likely to become endangered, at least locally, in the near future

• Vulnerable: naturally rare or have been locally depleted to a level that puts them at risk

ESA regulates a wide range of activities involving Endangered Species:

regulates a wide range of activities involving Endangered Species:
• Taking (harassing, harming, pursuing, hunting, shooting, killing, capturing, or collecting) either accidentally, or on purpose.
• Selling
• Importing into or Exporting out of the U.S.
• Possessing
• Transporting or Shipping

CITES

Convention on International Trade in Endangered Species

minimum viable population

minimum population size required for long-term viability of a species

Founder Effect

genetic drift that occurs after a small number of individuals colonize a new area

Demographic Bottleneck

A population founded when just a few members of a species survive a catastrophic event or colonize new habitat geographically isolated from other members of the same species.

Genetic drift

A change in the gene pool of a population due to chance

Private Land and Critical Habitat

Private land is essential in endangered species protection.
• Eighty percent of habitat for more than half of all listed species is on nonpublic property.
Habitat Conservation Plans (HCP)
• Landowners are allowed to harvest resources or build on part of their land as long as the species benefits overall.

Lacey Act (1900)

The Lacey Act protects both plants and wildlife by creating civil and criminal penalties for a wide array of violations. It prohibits trade in wildlife, fish, and plants that have been illegally taken, transported or sold.

Hunting laws are designed to

Protect game by establishing hunting season

US Fish and Wildlife Service

is a federal government agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats. The mission of the agency reads as "working with others to conserve, protect, and enhance fish, wildlife, plants and their habitats for the continuing benefit of the American people."

National Parks System

established by the United States/Roosevelt to preserve historic sites & habitats of many plants & animals.
• Park system sets high standard for managing biodiversity
• Established for protection of habitat and preservation for human use
• Parks protect sensitive habitat
• Some suffer from overuse/visitation

Gradual change in the following environmental factors affects Landscape Biodiversity

• Elevation
• Temperature
• Growing seasons
• Water availability (Precipitation, Proximity to streams)
• Variation in soil (e.g., soils on high mountain often more acidic than those in low valleys)

Ecological (landscape) biodiversity

- different habitats, niches, species interactions
- measures richness and complexity of a community

Species (community) biodiversity

- different kinds of organisms, relationships among species
- measures number of different kinds of organisms within a community

Genetic (population) biodiversity

- different genes & combinations of genes within populations
- measures variety of different versions of same genes

Without genetic diversity...

- species could not compete in the different environmental conditions across their geographic ranges and through time
- a population might more easily fall victim to parasites and pathogens.

Global pattern based on 4 factors:

1. Net primary production (warm weather near equator promotes higher production)
2. Past disturbance (tropical regions experienced less disturbance)
3. Habitat gradients (tropics: lack of seasons causes sharper distinctions of habitat)
4. Ecosystems complexity (Tropical regions favor the evolution of organisms with structures that increase habitat diversity)

Ecotourism

A form of tourism that supports the conservation and sustainable development of ecologically unique areas