Section I: General Principles of Ecology ECOLOGY ECOLOGY – how organisms interact with one another and with their environment ENVIRONMENT ENVIRONMENT – living and non-living components ABIOTIC – non-living component or physical factors as soil, rainfall, sunlight, temperatures ABIOTIC – non-living component or physical factors as soil, rainfall, sunlight, temperatures BIOTIC – living component are other organisms BIOTIC – living component are other organisms.

Earth, air, fire, water Modifiers of the Abiotic Environment Competitors mutualistsAtmosphere commensals chemical parasites physical SymbiontsSubstrate PredatorsWater Food (prey)Light ConspecificsHeat BIOTIC componentsABIOTIC components Environment of an Organism Four elements of ancient Greek philosophy:

ECOLOGICAL ORGANIZATION INDIVIDUAL INDIVIDUAL – individual organisms POPULATION POPULATION – organisms of same species in same area (biotic factors) COMMUNITY COMMUNITY – several populations in same area (biotic factors) ECOSYSTEM ECOSYSTEM – community plus abiotic factors BIOSPHERE BIOSPHERE – all ecosystems on earth

ECOLOGY OF INDIVIDUALS Homeostasis – delicate balance of a stable state Homeostasis – delicate balance of a stable state Components Components Physiological Ecology Physiological Ecology Temperature and Water Balance Temperature and Water Balance Light and Biological Cycles Light and Biological Cycles Physiological Ecology and Conservation Physiological Ecology and Conservation

INTERACTIONS AMONG SPECIES Interactions Interactions Interspecific competition Interspecific competition Predation Predation Exploitation Exploitation Symbiosis Symbiosis

Niches and Habitats The place where an animal lives is called its habitat. An animal lives where it can find food, water, shelter and a mate. Combined, these characteristics are called the organism’s “niche” The Niche is the organisms way of life within an ecosystem.

Niche The niche of a species consists of: Its role in the ecosystem (herbivore, carnivore, producer etc) Its tolerance limits (e.g. soil pH, humidity) Its requirements for shelter, nesting sites etc etc, all varying through time

The niche as a two-dimensional shape Niche represented by a 2-dimensional area Species A

Separate niches No overlap of niches. So coexistence is possible Species A Species B

Overlapping niches Interspecific competition occurs where the niches overlap Species C Species B

Species C Specialisation avoids competition Evolution by natural selection towards separate niches Species B’ Species C’ Specialisation into two separate niches Species B

This niche is not big enough for the both of us! Species A Species D Very heavy competition leads to competitive exclusion One species must go

Total exclusion Species A has a bigger niche it is more generalist Species E has a smaller niche it is more specialist Specialists, however, do tend to avoid competition Here it is total swamped by Species A

Example: Squirrels in Britain The Red Squirrel (Sciurus vulgaris) is native to Britain Its population has declined due to: Competitive exclusion Disease Disappearance of hazel coppices and mature conifer forests in lowland Britain

The Alien The Grey Squirrel (Sciurus carolinensis) is an alien species Introduced to Britain in about 30 sites between 1876 and 1929 It has easily adapted to parks and gardens replacing the red squirrel

Today’s distribution Red squirrelGrey squirrel

Carnivores Some animals, like the kingfisher, eat only other animals. These animals are called “carnivores”.

Herbivores Some animals do not eat other animals. They survive on plants and are known as “herbivores”.

Omnivores Some animals, like us, eat both plants and animals. These animals are called “omnivores”.

Consumers “Consume” means “eat”. Animals are consumers because they “eat” (consume) food provided by plants or other animals.

Producers Plants are living organisms. They need nourishment to survive. But… Plants do not eat other plants or animals. Plants are called producers, because they make their own food inside themselves.

Predator A predator eats other animals. Cats eat fish.So do bears!

Prey Any animal which is hunted and killed by another animal for food is prey. Predator Prey

Types of Species Interactions Neutral – two species do not interact Neutral – two species do not interact Mutualism – both benefit Mutualism – both benefit Commensalism – one benefits, other neutral Commensalism – one benefits, other neutral Parasitism – one benefits, one harmed Parasitism – one benefits, one harmed but not killed Predation – one benefits, other killed Predation – one benefits, other killed

Predator - Prey Relationship

Biogeochemical Cycles Hydrologic Cycle Hydrologic Cycle Phosphorus Cycle Phosphorus Cycle Nitrogen Cycle Nitrogen Cycle Carbon Cycle Carbon Cycle

Hydrologic (Water) Cycle

Phosphorus Cycle

Nitrogen Cycle

Carbon Cycle

Food Chain rose plant  aphids  beetle  chameleon  hawk rose plant  aphids  beetle  chameleon  hawk Producer 1 st order Consumer or Herbivore 2 nd order Consumer or 1 st order Carnivore 3 rd order Consumer or 2 nd order Carnivore 4 th order Consumer or 3 rd order Carnivore Decomposers – consume dead and decaying matter

Food Web

ECOLOGY OF ECOSYSTEMS Energy Flow Energy Flow Energy Flow Pyramids Energy Flow Pyramids Bio-mass Pyramids Bio-mass Pyramids Community Succession and Stability Community Succession and Stability Nutrient Recycling – nutrient cycles Nutrient Recycling – nutrient cycles

Energy vs Nutrient Nutrients – cyclic (Biogeochemical Cycles) Energy flow – one way

Ecologic Pyramids Ecological pyramid - a graph representing trophic level numbers within an ecosystem. The primary producer level is at the base of the pyramid with the consumer levels above. Numbers pyramid - compares the number of individuals in each trophic level. Numbers pyramid - compares the number of individuals in each trophic level. Biomass pyramid - compares the total dry weight of the organisms in each trophic level. Biomass pyramid - compares the total dry weight of the organisms in each trophic level. Energy pyramid - compares the total amount of energy available in each trophic level. This energy is usually measured in kilocalories. Energy pyramid - compares the total amount of energy available in each trophic level. This energy is usually measured in kilocalories.

Numbers Pyramid

Biomass & Energy Flow Pyramids

Limiting Factor Any factor which limits a population’s growth

Growth Curves

Human Population

An Introduction to Biomes

Aquatic and terrestrial biomes (Biome = major ecosystem type)

Climate Four abiotic factors determine climate Sunlight Temperature Wind and Ocean currents Precipitation Macroclimate Global, regional, local climate Microclimate Details of environmental conditions in small spaces Forest floor Under rock or log

Climate Temperature Affected by sunlight But much more so by: Ocean currents

Climate Precipitation Warm moist air carried by winds Condensation

Biomes Distribution of major habitat types strongly influenced by climate

Aquatic biomes cover about 75% of the earth’s surface - Wetlands - Lakes - Rivers, streams - Intertidal zones - Oceanic pelagic biome - Coral reefs - Benthos

Wetlands: includes marshes, bogs, swamps, seasonal ponds. Among richest biomes with respect to biodiversity and productivity. Very few now exist as they are thought of often as wastelands.

Marine environment with zonation.

Coral Reefs occur in neritic zones of warm, tropical water, dominated by cnidarians (corals); very productive, protect land from storms; most are now dying from rise in global temperatures

Deep-sea vent: Occurs in benthic zone; diverse, unusual organisms; energy comes not from light but from chemicals released from the magma.

Terrestrial biomes - Tropical forest - Savanna - Desert - Chaparral - Temperate grassland - Temperate deciduous forest - Coniferous forest - Tundra

Tropical Forest: Vertical stratification with trees in canopy blocking light to bottom strata. Many trees covered by epiphytes (plants that grow on other plants).

Example of Tropical, Dry Forest

Savannah: exotic grassland with larger animal species more common than a temperate grassland (more energy coming in = more energy going up the food chain)

Desert: Sparse rainfall (< 30 cm per year), plants and animals adapted for water storage and conservation. Can be either very, very hot, or very cold (e.g. Antarctica)

Chaparral: Dense, spiny, evergreen shrubs, mild rainy winters; long, hot, dry summers. Periodic fires, some plants require fire for seeds to germinate.

Temperate Grassland: Marked by seasonal drought and fires, and grazing by large animals. Rich habitat for agriculture, very little prairie exists in US today.

Temperate Deciduous Forest: Mid-latitudes with moderate amounts of moisture, distinct vertical strata: trees, understory shrubs, herbaceous sub-stratum. Loss of leaves in cold, many animals hibernate or migrate then. Original forests lost from North America by logging and clearing.

Coniferous forest: Largest terrestial biome on earth, old growth forests rapidly disappearing, usually receives lots of moisture as rain or snow.

Tundra: Permafrost (Permanent frozen ground), bitter cold, high winds and thus no trees. Has 20% of land surface on earth.