BISC208 Exam 3

Population

A group of individuals of the same species living in a particular geographic area

Community

All the populations of organisms living close enough together for potential interaction (or different species)

Ecosystem

Both the abiotic and biotic components of the environment in an area

Landscape

An array of ecosystems usually visible from the air as distinctive patches

Biosphere

All of Earth that is inhabited by life

Equatorial regions receive sunlight

More directly

Higher latitudes receive sunlight

At more of a slant

Why do the tropics have such abundant precipitation?

As air rises, it cools and releases much of its water content

What creates deserts?

High-altitude air masses spread away from the equator and descend again at latitudes of about 30 degrees north and south, where the descending dry air absorbs moisture from the land

Ocean currents

Have a profound effect on regional climates

Photic zone

Near the surface of the water, where light penetration is sufficient for photosynthesis

Why do coastal areas have productivity?

There are more nutrients in the photic zone due to run-off and shallower water

What is water like near the source of rivers and streams?

Narrow, fast-moving, cold, low in nutrients, clear

What is water like downstream rivers and streams?

Wide, slow, warm, high in nutrients and microorganisms, murky

How may the same biome occur in geographically distant places and what is that called?

The climate is similar; convergent evolution

Tropical rain forests

• High temperature

• High precipitation

• High productivity

• Poor soil with high decomposition and leaching

Savannas

• Warm

• Relatively dry

• Grasses and scattered trees

• Large herbivores and their predators

Deserts

• Driest of all terrestrial biomes

• Very hot or very cold

• Plants and animals adapted to low and variable rainfall

Chaparral

• Cool, rainy winters

• Hot, dry summers

• Spiny shrubs

• Mediterranean

• Vegetation adapted to periodic fires

Temperate grasslands

• Cold winters

• Relatively low precipitation

• Mostly treeless, except along rivers or streams

• Support large grazers

Temperate broadleaf forests

• Wide-ranging temperatures

• High annual precipitation

• Trees that drop their leaves in the fall

• Richer soils than tropical forests

• Slower decomposition at lower temperature

• Leaf litter adds organic material

Coniferous forests

• Cone-bearing evergreen trees

• Taiga has long, cold winter and short, wet summers

• Temperate rain forests

Tundra

• Extremely cold and dry

• Permafrost

• Plants and animals adapted to extreme cold, high winds, and short summers

Polar ice

• Covers much of the Arctic Ocean and Antarctica

• Only a few small plants and animals can survive here

Innate behaviors

Happen from birth and involve something that triggers their release

What are most behaviors?

A mixture of innate and learned

Foraging behavior

Involved weighing costs and benefits

Territory

An area where individuals exclude members of their own species, adjusted according to the costs and benefits of maintaining them

Benefits of territory

Access to food, mates, and shelter

Costs of territory

Energy costs, and injury or death

Communication

Behavior that depends upon the environment an organism lives in

Auditory communication

Sounds, calls

Visual communication

Courtship dances, signals

Chemical communication

Scent trails, pheromones

Tactile communication

Touching, grooming

Benefits of group living

Increased vigilance and food gathering, kin selection, minimizing heat and water loss, grooming, opportunities for energy savings

Costs of group living

Increased attack rates by predators, increased competition, inbreeding, infanticide, oxygen depletion, increased disease transmission

Altruism

Behavior that benefits others at a cost to oneself

Group selection

Suggests natural selection produces outcomes beneficial to a group

Kin selection

The idea that altruistic behaviors benefit individuals closest to the one performing the behavior

Population ecology

Study of changes in population size and factors that regulate populations over time

Factors that increase population size

Birth and immigration

Factors that decrease population size

Death and emigration

Population density

The number of individuals of a species per unit area or volume

Dispersion pattern

The way individuals are spaced within their area

Clumped pattern

Individuals are grouped in patches due to unequally distributed resources and it can help protect against predators

Uniform pattern

Individuals are equally spaced in the environment and it can be due to territorial interactions

Random pattern

Individuals are spaced in an unpredictable way and can be due to the something like windblown seeds

Life tables

Track survivorship, the change of an individual in a given population surviving to various ages

Survivorship curves

Plot survivorship as the proportion of individuals from an initial population that are alive at each age

Survivorship curve I

High survivorship in beginning of life, high death at end of life (ex. humans)

Survivorship curve II

Steady rate of death throughout entire life (ex. squirrels)

Survivorship curve III

High rate of death at beginning of life (ex. clams)

Interspecific interactions

Relationships with individuals of other species in the community

Competition

neg, neg

Mutualism

Pos, pos

Predation

Pos, neg

Herbivory

Pos, neg

Parasites and pathogens

Pos, neg

Ecological niche

Sum of an organism’s use of the biotic and abiotic resources in its environment

What type of relationship is reef-building corals and dinoflagellates?

Mutualistic

Herbivores and plants undergo what?

Coevolution

Internal parasites

Nematodes and tapeworms

External parasites

Mosquitoes, ticks, and aphids

Pathogens

Disease-causing microscopic parasites that include bacteria, viruses, fungi, and protists

Consumers are what?

Heterotrophs

Primary consumers eat what?

Producers

Herbivores eat what?

Primary consumers

Secondary consumers eat what?

Herbivores

Tertiary consumers eat what?

Secondary consumers

Decomposers are mainly what?

Prokaryotes and fungi

What defines species diversity?

Species richness and relative abundance

Species richness

The number of species in a community

Relative abundance

The proportional representation of a species in a community

Keystone species

Impact on community is larger than its biomass or abundance and it occupies a niche that holds the rest of its community in place

Disturbances

Events that damage biological communities, including storms, fires, floods, drought, and human activity

Ecological succession

The disturbed area may be colonized by species that are gradually replaced by other species

Primary succession

Begins in virtually lifeless area with no soil, such as the rubble left by a retreating glacier or fresh volcanic lava flows

Secondary succession

Occurs when a disturbance destroys an existing community but leaves the soil intact, such as when an abandoned farm field returns to forest

Energy flow

Moves through an ecosystem

Chemical cycling

Occurs within the ecosystem

Primary production

The amount of solar energy converted to chemical energy by an ecosystem’s producers for a given area during a given time period

Biomass

The amount of living organic material in an ecosystem

Biogeochemical cycles

Include biotic components and abiotic components

Abiotic reservoirs

Where nutrients accumulate outside organisms

The carbon cycle depends on

Photosynthesis and respiration

The phosphorus cycle depends on

The weathering of rock

The nitrogen cycle depends on

Bacteria

What organisms receive the greatest adverse effects of climate change?

Ones that live at high latitudes and high elevations

Phenotypic plasticity

The ability to change phenotype in response to environmental conditions within the normal range of expression for an individual’s genotypes

What populations adapt quickly to climate change?

Ones with high genetic variability and short life spans

What does biodiversity encompass?

Ecosystem diversity, species diversity, and genetic diversity

Biggest threat to biodiversity

Human alteration of habitats

2nd largest threat to biodiversity

Invasive species

The release of CFCs has what?

Promoted the thinning of the ozone layer

Biological magnification

Concentrates certain chemicals as they pass through the food chain

How much plastic is added to the ocean annually?

about 8 million tons