IB Ecology

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Ecology

Ecology

The science of the relationships between organisms and their environments.

Organism

an individual living thing that uses energy, reproduces, responds, grows, and develops

Species

a group of similar organisms that can breed and produce fertile offspring

Population

group of individuals of the same species that live in the same area at same time

Community

a number of different populations living and interacting in the same area (all the living things in an area)

Ecosystem

a community and its abiotic environment (all the living things in an area interacting with the non-living things)

Autotroph

• also known as a producer

• an organism capable of making its own food from inorganic substances using light or chemical energy.

• eg. Green plants, algae, and certain bacteria

Heterotroph

An organism that obtains organic food molecules by consuming other organisms or substances derived from them.

Carbon cycle

the continuous process by which carbon is exchanged between organisms and the environment

Energy flow

energy from the sun is captured by producers and passed along food chains by consumption and decomposition. Energy is lost at each stage.

Trophic level

each step in a food chain or food web. producers are at level 1.

Food web

network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem (all interconnected food chains)

Food chain

shows the transfer of energy along a feeding relationship from producers along the different trophic levels

producer --> primary consumer --> secondary consumer --> tertiary consumer

eg. grass --> cricket --> mouse --> snake

Pyramid of energy

a diagram to show the energy contained in a food chain, web or community

10% Rule

the idea that only 10% of the energy in one trophic level gets passed onto the next trophic level due to losses of heat (respiration), feces, decomposition, etc

Producer

organism that can capture energy from sunlight or chemicals and use it to produce food from inorganic compounds; also called an autotroph

Consumer

organism that relies on other organisms for its energy and food supply; also called a heterotroph

Primary Consumer

Consumer that feeds directly on producers; (animals that feed on plants, algae or phytoplankton)

Secondary Consumer

An organism that eats primary consumers; (animals that generally feed on herbivores)

Tertiary Consumer

An organism that eats secondary consumers; The third trophic level of consumer in a food chain; A carnivore that eats other carnivores.

Detritivore

A specific type of heterotroph that eats plant and animal remains and other dead matter (ex. vultures, earthworms, crabs, etc.)

Saprotroph

A specific type of heterotroph that lives on or in non-living organic matter, secreting digestive enzymes into it and absorbing the products of digestion (e.g. mushrooms, bacteria); = a type of decomposer

Precautionary Principle

The principle that states that when an activity raises threats of harm to human health or to the environment, safety should prevail and control measures should be initiated even if cause-and-effect relationships are not fully established

Detritus

nonliving organic matter; typically includes decaying dead organisms as well as fecal matter

Habitat

the area where an organism lives, including the biotic and abiotic factors that affect it

Limiting factor

factor that is needed for continued population growth - if in short supply it will stop the population growing or cause decline

External factor

any living or nonliving factor that impacts the survival of an organism, population, or community (can be a limiting factor or a non-limiting factor)

Abiotic

non-living

Biotic

living

Greenhouse effect

Natural phenomenon which maintains temperatures required for life to live on Earth where short wave (visible light) radiation from sun is absorbed by the surface of the planet and re-radiated at longer wavelengths which get trapped by gases in the atmosphere

Potential problems associated with climate change

1. ice habitats are melting (destruction of habitats)

2. flooding (destruction of habitats)

3. desertification

4. more extreme weather events

5. species extinction

6. movement of species further north

7. destruction of food webs

Chemoautotrophs

organisms that obtain energy from chemicals to make their own food; Autotrophic bacteria that derive energy from inorganic sulfur compounds; often live in deep-ocean vents

Quadrat Sampling

Using a known small area at random to count organisms within that area. The number of organisms within that area can give an approximate estimate of the population of that particular species in a larger area.

(Line) Transect

use string across a place where you collect data, collect the data of whatever passes the string

Plant/animal distribution

The number of a particular organism in an given area (measured using quadrats and represented either as percentage coverage or organisms per squared area)

limits of tolerance

The range of a particular environmental factor (e.g. temperature, soil pH, elevation, etc) that an organism can survive within

optimal zone

The optimal range of an environmental factor that an organism survives best in

zone of stress

Within the limits of tolerance but the range where the envirnmental factor means an organism is struggling to survive

zone of intolerance

The range of an environmental factor where an organism is unable to survive (e.g. too hot/cold, too salty, not enough oxygen, etc)

Niche concept

The environmental role that and organism plays within its environment

Fundamental Niche

all of the places a species can live if no competition; The entire range of resource opportunities an organism is potentially able to occupy within an ecosystem

Realised/Applied Niche

the actual areas a species tends to occupy due to competition with other organisms in the same area

Competitive exclusion principle

The idea that two organisms can't occupy the exact same niche due to competition

Keystone species

A species that plays an important role in its environment and helps to maintain the biodiversity of the ecosystem

Natality

Birth rate; increases population size as offspring are added to the population

Immigration

Movement of individuals into a population

Emigration

Movement of individuals out of an area.

Mortality

Death rate

Competition

A common demand by two or more organisms upon a limited supply of a resource; for example, food, water, light, space, mates, nesting sites.

Predation

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

Parasitism

A relationship in which one organism lives on or in a host and harms it (+/-)

Mutualism

A relationship between two species in which both species benefit (+/+)

Biomass

-the mass of living biological organisms in a given area or ecosystem at a given time.

-A measure of the total dry mass of organisms within a particular region.

Biosphere

The area on and around Earth where life exists.

Biome

A group of ecosystems that share similar climates and typical organisms.

Invasive Species

species that enter new ecosystems and multiply, harming native species and their habitats

Biomagnification

accumulation of pollutants at successive levels of the food chain; due to inability to excrete pollutants and bioaccumulation

Bioaccumulation

The build up of pollutants in a particular trophic level of a food chain as the pollutants can't be excreted

Primary succession

The series of stages of growth in plant life on newly exposed rock (= bryophata, grasses and small plants, small trees and shrubs, larger trees)

Secondary succession

The series of stages of growth in plant life in an area where the previous ecosystem has been destroyed (e.g. after a fire or clearance for agriculture)

Nutrient cycling

The cyclic systems in which certain elements are exchanged between the biotic and abiotic realms. e.g Carbon, Nitrogen and Phosphorus cycles.

Microplastics

Tiny pieces of plastic that can cause damage to zooplankton and other small aquatic creatures

Macroplastics

Larger pieces of plastic debris that causes problems for large fish and seabirds through ingestion and even strangulation.

Closed systems

Systems where energy can be exchanged but matter can not - e.g. mesocosms

DDT

A pesticide used to kill mosquitoes to control malaria - a good example of the problems caused by biomagnification

Biotic index

A measure of the relative abundance of indicator species to compare pollution or damage to an environment

Biodiversity

The richness, variety and abundance of species in a given ecosystem or habitat

Simpson's diversity index

A way to estimate biodiversity by looking at the relative abundance of species in a given area

Nature reserves

Protected areas of land where building, poaching and and farming are restricted. Usually run by government agencies.

In situ conservation

Protection of species through efforts within the natural habitat of that species

Ex situ conservation

Protecting species away from their natural habitat (e.g. introduction to new areas or zoo breeding programs)

The corridor effect

Pockets of forest or nature reserves will not support biodiversity well unless there are corridors (areas of natural land) connecting them.

The edge effect

Biodiversity is likely to be poorer on the outskirts of nature reserves as the organisms are more prone to influences from outside, e.g. poachers, pollution, etc

transpiration

the emission of water vapor from the leaves of plants