Ecology Test

Ecology

The study of interactions between living things & their surroundings

Organism

An individual living thing

Population

A group of the same species living in an area

Community

A group of different species living in an area

Ecosystem

The living & nonliving things in a given area

Biome

A global community of organisms based on climate

Biotic

Living things

Abiotic

Nonliving things

Biodiversity

The variety of living things in an ecosystem

Keystone Species

A species with a very large effect on its ecosystem

Producer (autotroph)

Gets its energy by making its own food

Consumer (heterotroph)

Gets its energy by eating other living things

Herbivores

Organisms that only eat plants

Carnivores

Organisms that only eat meat

Omnivores

Organisms that eat both plants & animals

Detritivores

Organisms that eat dead matter

Decomposers

Detritivores that break down organic matter into nutrients that are recycled back into the environment

Specialist

Organisms with a specific diet

Generalist

Organisms with a varying diet

Trophic Levels

The levels in a food chain

Energy Pyramid

Shows the distribution of energy among trophic levels

90%

Between trophic levels, _____ of the energy is lost into the atmosphere as heat

Biomass Pyramid

Measures the total dry mass of organisms in a given area

Pyramid of Numbers

Measures the number of individual organisms by trophic level

Ammonification

The process turning waste & decay into ammonia (NH3)

Nitrification

The process changing ammonia (NH3) into nitrates (NO3)

Assimilation

The absorption of nitrates (NO3) by plants & animals

Denitrification

The process changing nitrates (NO3) into nitrogen (N2)

Leaching

The process of phosphorus leaving the soil into a body of water

Sedimentation

The process of forming new rocks with phosphorus

Geologic Uplifting

The process of bringing phosphate up from rocks in a body of water to hills

Nitrogen Fixation

The process turning nitrogen into ammonia (NH3)

Habitat

Where a species lives

Niche

A species’ job, and how it lives within a habitat, including food, abiotic conditions, & behavior

Competitive Exclusion

2 species competing for the same resources, leading one species to be pushed into another niche or go extinct

Niche Partitioning

Dividing of niche between 2 competing species

Ecological Equivalents

Species occupying similar niches in different geological regions

Interspecific Competition

Competition between different species

Intraspecific Competition

Competition between the same species

Predation

Process by which one organism feeds on another

Symbiosis

An ecological relationship between organisms of a different species

Mutualism

A symbiotic relationship in which both species benefit from each other

Commensalism

A symbiotic relationship in which one species benefits and the other is neutral

Parasitism

A symbiotic relationship in which one organism benefits while the other is harmed

Population Density

The number of individuals living in an area

\# of individuals/area

Formula for population density

Clumped, uniform, random

Types of geographic dispersion

Type I Survivorship Curve

Dashed line

Type II Survivorship Curve

Filled-in line

Type III Survivorship Curve

Dotted line

Births, immigration, emigration, & deaths

Factors determining population size

Exponential Growth

Occurs when population size increases dramatically over time

Logistic Growth

Begins with slow growth, then brief exponential growth, before leveling off at a stable size

Carrying Capacity

The maximum number of individuals in a species an environment can support

Competition, predation, parasitism, & disease

Density-dependent limiting factors

Unusual weather, natural disasters, & human activity

Density-independent limiting factors

Primary succession

Development of an ecosystem in a previously uninhabited area

Secondary succession

Reestablishment of a damaged ecosystem where soil was left intact

Pioneer Species

First organisms to move into an area (typically lichens or moss)

Smog

Air pollution caused by the interaction of sunlight with pollutants from fossil fuels

Particulates

Microscopic bits of dust, metal, and fuel

Ozone

Produced by reactions of nitrogen oxide & oxygen

Acid Rain

Chemicals from fossil fuel emissions dissolve into rain, causing this

Greenhouse Effect

The effect in which greenhouse gasses act like an insulator, slowing the loss of heat through the atmosphere

Indicator Species

A species providing a sign of the quality of an ecosystem’s environmental conditions

Biomagnification

Accumulation of toxins in the food chain

increases

As pollutants move up the food chain, their concentration ______

Habitat Fragmentation

When a barrier prevents an organism from accessing its entire range

Invasive Species

An organism brought to an ecocystem by humans that harms the native species