Introduction to ecology

Introduction to ecology

• Ecology and evolution are dependent upon one another
• Diversity of life on Earth is a result of evolution playing our in changing ecological contexts over the course of Earth’s history.

Ecology

• Ecology is the study of how organisms interact with each other and their environment.

Ecological levels

• Organismal ecology - explores morphological, physiological, and behavioral adaptations that increase fitness in a given environment
• Population ecology - examines changes in number and distribution of individuals over time (i.e. births and deaths, where they’re found)
• Community ecology - examines interactions between species and the consequences of those interactions (i.e. cooperative hunting between dif types of whales)
• Ecosystem ecology - examines relationships between biotic (living) and abiotic (non-living) factors in an environment. (behavior and how its causing an interaction between the whales and the abiotic factors there bc they stir up sediment.)
• Global ecology - examines the biosphere interactions with the geosphere, hydrosphere, and atmosphere.

Conservation Biology

• Conservation biology is applied to ecology
  • Restore genetic diversity
  • Restore species diversity
  • Restore ecosystem function

Distribution and abundance

• Niche is the range of conditions, resources of an organism.
• Biotic - factors are the living factors in an ecosystem
• Abiotic - factors are the non-living factors in an ecosystem

Past and present

• Abiotic factors
  • Present
    • Sunlight
    • Temp
    • Humidity
  • Past
    • Mountains
    • Valleys
    • Sea level
• Biotic factors
  • Present
    • predator/prey
    • Parasitism
    • Competition
    • Organisms
  • Past
    • Land use
    • Harvesting
    • Dispersal

Climate patterns

• Weather - short-term atmospheric conditions
• Climate long-term atmospheric conditions

Temperature

• Dependent upon amount of sunlight
• Angle at which sunlight hits surface
• Less energy with lower angle

Precipitation

• Hadley cells - the major cycle in global air circulation
  • Air heated at equator expnads and rises, and warm air holds moisture
  • Air cools as it rises, producing rain
  • Air pushed towards poles, sinks
  • Air warms as it sinks, holds more water

Coriolis effect

Seasonality

• Seasons are regular, annual fluctuations in temperature and/pr precipitation caused by Earth’s tilt

Mountains

• Temperature decreases as elevation increase
• Affects precipitation patterns
  • Winds from ocean carry moisture-laden air to land
  • Windward side of range receives rain as air rises and cools
  • Leeward side is in a rain shadow and dry

Oceans

• Water has a high specific heat
• Oceans moderate temperatures
• Ocean currents affect climate
• Gyres are large ocean currents
  • Clockwise Northern hemisphere
  • Counterclockwise Southern hemisphere
• Warm water to cold latitudes, cold water to warm

Biomes

Ecology - the study of how organisms interact with each other and their environment

Biomes

• Biomes are regions characterized by distinct abiotic characteristics and dominant vegetation types

Terrestrial biomes

• Abiotic conditions determined by climate:
  • Temperature
  • moisture
  • Sunlight
  • Wind
• Plant distribution and abundance:
  • Average annual temp, precipitation
  • Variation in temp, precipitation
• Abiotic conditions influence net primary productivity
  • Represents organic matter available as food
  • Biomass generated via carbon fixation - carbon oxidized during cellular respiration

Arctic tundra

• Arctic regions of northern hemisphere
  • Less than 10in rain annually
  • 6-10 months below freezing
  • 6-10 weeks for plant growth
• Permafrost is soil layer frozen year-round
• Blueberries, lingonberries, Labrador tea, reindeer lichen

Borela forest

• High northern latitudes
  • Range from below freezing to mid-60s
  • Roughly 18-week growing period
  • Roughly 30 in precipitation average
• Dominated by conifers-pine, spruce, fir
• Some deciduous tress - birch, willow, poplar
• Ferns, mosses, lichen

Temperate forest

• Eastern North America, Europe, Asia
  • Seasons with distinct winter
  • Fertile soil, precipitation distributed year-round
  • Deciduous, coniferous, mixed, rainforest

Temperate Grassland

• Prairie or steppe
• Primarily grass, shrubs
• Temperate climate
  • Semi-arid to semi-humid
  • Distinct winter
  • Moderate rainfall

Desert and Dry Shrubland

• Occur at 30 degrees latitude
  • Less than 10 in rain per year
  • Cactus, low shrubs
  • Extreme temperatures
    • 135 degrees Fahrenheit in Death Valley
    • -128.6 degrees Fahrenheit in Antartica

Tropical Rainforest

• Equatorial regions
  • Year-round growing conditions
  • 66-390 in. rain
  • Over 64 degrees fahrenheit every month
  • Highly diverse flora - plants are evergreen
  • South America has 40% of the world biodiversity.
    • 25% of the world forests.
• Aquatic Biomes
  • 70% of Earth’s surface
  • Abiotic factors
    • Salinity (
    • Water depth
    • Water flow
    • Nutrient availability

Oceanic Zones

• Intertidal: shorelines affected by tides
• Epipelagic: surface to 200m, where light penetrates
• Benthic: ocean floor
• Aphotic: below 200m, light cannot penetrate

Water flow

• Affects oxygen and nutrient availability
  • Fast moving water → more O2, low nutrients
  • Slow moving water → lower O2, high nutrients

Nutrient Availability

• Water picks up nutrients as it flows
• Estuaries where river meets ocean are nutrient-rich
• Oceanic currents cause upwelling of nutrients to surface
• Lake Turnover causes nutrient cycling in temperate lakes

Lakes and Ponds

• Freshwater
• Northern latitudes, created by glaciers
  • Pond: 0.5 acres max 6ft deep
  • Lake: bigger than 1 acre

Freshwater Wetlands

• Freshwater
• Shallow, saturated soil
• Includes marshes, swampls, bogs

Streams

• Freshwater
• Move constantly in one direction
• Creeks are small, rivers are large

Estuaries

• freshwater/marin
• Form where river meets ocean
• Highly productive environments

Oceans

• Marine
• Continous body of saltwater
• Average depth - 12,000 ft
• Huge species diversity

Behavioral Ecology

• Behavior is reaction to some soft of stimulus
• Behavioral ecology - focuses on behavioral adaptations that have evolved as a result of ecological selection pressure

Causes of behavior

• Proximate causation - explains how behaviors occur
• Ultimate causation - explains why behaviors occur

Ex: ducks?

Types of behavior

• Innate behavior - is passed genetically from parent to offspring
• Learned behavior - is an enduring change resulting from a specific experience
• Innate Ex: hunting dogs - innate behavior. Specifically bred to have retreiving behaviors.
• The learned behaviors are like telling them to sit or for a treat. They do it because they are motivated by the result of their actions.

Choices involve trade-offs

• Each behavior has costs and benefits, resulting in fitness trade-offs
• Cost-benefit analysis is used to quantify behavioral choices
• Ex: peacocks having colorful feathers, which attract the females and allows them to reproduce, but the tradeoff is that the are more easily huntable and its harder to hide. It is harder for them to fly because the tail feathers are heavier.

Foraging behavior

• Fruit flies
  • Rovers - move around a lot, offspring of rovers tend to be rovers
  • Sitters - offspring of sitters tend to be sitters
• Optimal foraging is the hypothesis that animals will maximize their feeding efficiency
  • Most food for least amount of energy
• Cuttlefish
  • Choose number of prey → hungrier animals eat more
  • Choose size of prey → eat fewer large
  • Choose quality of prey → eat fewer live prey

Mate Choice

• Choosing a male is not as simple as it sounds.
  • Promiscuity - (many:many) EX: lady bugs
  • Polygamy - (one:many)
    • Polygyny - 1 male, many females EX: elk
    • Polyandry - 1 female, many males EX: honey bees
  • Monogamy - (one:one) EX: bald eagles
• Mating systems vary, even in individuals
• Mating systems are not always as they appear
• Mating behavior can serve functions other than reproduction

Mate choice EXs

• Anolis lizard sexual activity
  • Spring-like conditions → eggs
  • Breeding males → eggs earlier
  • Dewlaps removed → eggs slower
• Intersexual selection - when one sex chooses a mate
  • Ex: turkey, showing off, looking beautiful
• Intrasexual selection - when individuals of the same sex comete
  • Ex: deer or elk fighting for dominance

Moving about (migration)

• Migration - is long-distance movement associated with seasonal changes
• Piloting - uses familiar landmarks → follow parents
• Compass orientation - is specific direction → sun, stars, magnetic field
• True navigation - is a bility to locate a specific place → ex: green sea turtles

Cooperation

• Altruism costs individuals exhibiting behavior, benefits recipient
  • Costs the ind exhibiting the behavior, but benefits relatives
  • Can have this within killer whates, who never have their own children, but take care of others' babies. Like “it takes a village.”
  • Prairie dogs - alert their family members byt place themselves at risk
  • True altruism - humpback whale dying, another healthy male humpback whale swam under him and helped him go to the surface to breath, sang whale songs to him until he died, stayed with him
• Kin selection is natural selection that benefits relatives at expense of individual
• Reciprocal altruists help an individual who has previously helped them / likely to help them in the future
  • Monkeys will help groom ones who have groomed them in the past or someone who used to groom them.

Cooperation is within same species → benefits exceed costs

Mutualism is cooperation between different species

Populaltion Ecology

Population thinking

• Understanding variation in populations is key to understanding function and change over time

Distribution and Abundance

• An organism’s range is its geographic distribution
  • Temperature, rainfall
  • Geography
  • Food, competition
• Population density – the number of individuals per unit area – varies within range

Spatial distribution

Uniform - penguins

Random - dandelions

Chumped - elephants and deer

Demography

• Demography is the study of factors determining size and structure of populations
  • Birth
  • Death
  • Immigration → enter population
  • Emigration → leave population
• Age structure → how many of each age are alive?
• Generation time → mother’s first offspring to her daughter’s first offspring
  • 2 years to sexual maturity
  • 33 days incubation
  • This is for born owls?
• Survivorship → proportion of offspring that survive to a certain age
  • Survivorship curves
    • Type 1 → drops when old
      • humans
    • Type 2 → steady
      • hawks
    • Type 3 → low when young
      • Fish
• Fecundity → number of female offspring produced by each female
• Net reproductive rate → indicates whether population is decreasing or increasing

Life history

• Life history describes allocation of resources to growth, reproduction, survival
  • • Involves fitness trade-offs
    • Average traits in a population evolve
    • High fecundity, low survival
    • Low fecundity, high survival

Population growth

delta N /delta t = Births-Deaths+Immigrants-Emigrants

Exponential Growth / Density Independent Logistic Growth / Density Dependent

Population Size Limits

• What factors can limit population size?
  • Weather patterns
  • Disasters
  • Resources
  • Disease / Parasitism
  • Predation
  • Toxins
  • Social behavior

Population Crashes

• Resources consumed at faster rate than produced

Population Cycles

• Less drastic than crashes
• Cyclical patterns
• Which organism is controlling population?

Metapopulations

• Metapopulations are formed by many small patches of isolated populations
  • Some populations go extinct over time
  • Can be restored via dispersal
• Important for conservation biology
  • Larger subpopulations better
  • Genetic diversity important
  • Corridors connecting habitats

Community Ecology

Biological communities

• A community consists of all populations of different species that interact in a given area

Species interactions

• Fitness is the ability to produce viable, fertile offspring
• Commensalism (+/0)
  • One species benefits, other unaffected
  • Difficult to quantify
  • Example: epiphytic orchids
• Competition (-/-)
  • Individuals use same resources
  • Lowered fitness for both
  • Intraspecific in same species
  • Interspecific in different species
    • Direct → hyena steals food from lion
    • Indirect → finch consumes all food on a bush
• Consumption is when one organism eats/absorbs nutrients from another
• Predation occurs when a predator consumes prey
• Herbivores consume plant tissues such as leaves, stems, fruits, or roots
• Parasitism is when an organism lives on or in a host at the expense of the host
  • Endoparasites are inside of the host (ex. worms)
  • Ectoparasites are outside of the host (ex. ticks)
• Mimicry - monarchs(toxic) mimicked by viceroid, when one organism looks like another
• Camouflage - female birds duller in color to blend in while they sit on their eggs
• Escape behavior
  • Detect predators
  • Run, fly, jump, swim away
  • Ex: bunnies having big ears
• Defense chemicals are produced by some organism to ward of predators, herbivores
• Schooling/flocking can confuse predators, provide protection
  • Zebras have stripes to blend in to eachother
  • Fish swimming in schools
  • Bison take all the babies and put them in the middle to protect them
• For plants:
  • Defense armor/weapons
    • Thorns
    • Protective shells
    • Thick skin
• Mutualism (+/+)
  • Fitness benefits for both organisms
  • Does not involve altruism or being “nice”
  • Ex. flowering plants and pollinators

Community Structure

• Four key attributes:
  • Total number of species
  • Relative abundance and distribution
  • Sum of interactions among species
  • Physical attributes of the community
• Species richness measures the number of species in a community
• Species diversity weights number of species and their abundance
• Food chains link consumption interactions (ex. wolves eat elk)
• Food webs summarize food chains
• Keystone species has a disproportionately large effect on its natural environment relative to its abundance
  • Organism that is low in abundance but has a large impact on environment.
  • Ex: beavers - they can cause a lot of flooding, lakes to form and in turn changes which species and animals can live there
• Community structures are not entirely predictable!
• 12 identical sterile ponds, wait
• Test the types of plankton present
• Similar species, but unique species compositions

Community Dynamics

• A disturbance is a strong, short-lived disruption to a community
  • Fire
  • Flood
  • Windstorms
  • Large tree falling
  • Disease epidemics
• Succession occurs after disturbance
• Succession is the recovery after a disturbance
  • Primary succession removes soil
  • Secondary succession leaves soil intact
• Pioneer species tend to be weedy with high frequency and low survivorship

• Species interaction
  • Facilitation → improve habitat for later species
  • Tolerance → current species do not affect new
  • Inhibition → one species inhibits another
• 1988 Yellowstone NP fire burned nearly 794,000 acres – 36% of the park

Conservation Biology

• Focuses on studying, preserving and restoring biodiversity
  • EX: smithsonian, WWF, ocean conservancy
• A lot of biodiversity around the equator

Biodiversity

• Genetic diversity
  • Total genetic information
  • Number and relative frequencies of genes
• Species diversity
  • Richness – number of species
  • Diversity – richness and evenness
• Functional vs phylogenetic
  • Does a species play an important role?
  • Is a species near extinction?
• Ecosystem diversity
  • Communiuties plus abiotic factors
• Ecosystem function includes biological and chemical processes

Global Diversity

• ~1.5 million species named
• This is only a fraction!
• Estimates range from 5 – 10 million species!!
• Habitat destruction:
  • Logging
  • Dams
  • Filling wetlands
  • Plowing
  • Livestock
  • Mining
  • Development

Threats

• Overexploitation: unsustainable removal of organisms
  • Marine environments
  • 90% of large-bodied fish removed (sharks, tuna, cod, halibut)
• Invasive species
  • Exotic species → large population size, disrupt native species
  • Can cause or spread disease
• Pollution:
  • Industrial (sulfur, mercury, lead)
  • Pharmaceutical
  • Pesticides/herbicides
  • Runoff
  • Garbage
• Climate change
  • Polar ice, alpine habitats
  • Sea level rise
  • Shifts in biomes

Endangered species

• Very likely to go extinct
  • Extinct
  • Extinct in the wild
  • Critically endangered
  • Endangered
  • Vulnerable
  • Near threatened
  • Least Concern

Why do we care?

• Provisioning → ray materials
  • Food
  • Fuel
  • Fiber
  • Medicines
  • Water
  • Genetic resources
• Regulating → Earth life support
  • Climate moderation
  • Erosion control
  • Oxygen production
  • Water purification
  • Flood control
  • Waste decomposition
• Cultural → quality of life
  • Aesthetics
  • Recreation
  • Education
  • Spiritual value
  • Mental and physical health
• Supporting → enable all other services
  • Primary producers
  • Nutrient cycling
  • Pollination
  • Pest control

What can we do?

• EDUCATION
• Public outcry causes change
  • Anti-finning regulations
  • International ban on commercial whaling bc of public outcry
  • Regulation of animal harvest
• Earth Day on April 22nd
• Genetic restoration
  • INC genetic diversity in small populations
  • Florida panthers → success
  • Greater prairie chicken → success
  • Isle Royal wolves → failure
• 95% of world’s calories from 30 crops
• Seed banks
  • Preserve diverse and wild strains of crops
  • Some seeds not viable
  • Svalbard Grobal Seed Vault
    • Over 1 million distinct crop samples
    • 13,000 years of agricultural history
• Management plans
  • Invansive species
    • Global trade regulation
    • Inspections
    • Prevention vs. treatment
  • Threatened species
    • Endangered Species Act
    • Laws, regulations
• Ex situ conservation
  • Some species extinct in wild
  • Preserved in zoos, aquariums, etc
• Reintroduction to wild
  • Przewalski’s horse
  • Whooping crane
  • Peregrine falcon
  • California condor
  • Arabian oryx
• Wildlife corridors → undeveloped habitat connecting preserved areas
• 2021, Wildlife Corridors Conservation Act
• Protective areas are increasing
• Marine protective areas → no fishing
• Wildlife preserves, national parks
• Restoration
  • Erosion control
  • reforestation/revegetation
  • Removal of non-native species, weeds
  • Reintroduction of native species
• Accumulation of small changes can have a big effect

Biogeochemical Cycles

Ecosystems

• An ecosystem is made up of a community of interacting species in a region and abiotic factors
• Ecosystems connected by flow of energy and nutrients
• The biosphere consists of soil, water, and air surrounding Earth

Energy Flow

• Energy enters ecosystem via primary producers
  • Transform sunlight, inorganic compounds into organic molecules
  • Gross primary productivity is total chemical energy produced in a given time and area
• Primary producers use energy:
  • Cellular respiration
  • Growth
  • Reproduction
• Net primary productivity is gross primary productivity minus energy used
• Only 0.8% of total solar energy is used for everything else to use
• 55% of .8% used by primary producers

Energy flow

• Trophic levels are “feeding” levels
  • Consumers eat things
    • Primary primary producers
    • Secondary primary
  • Decomposers feed on remains, waste products

Food Webs

• Food chains show one possible pathway
• Food webs combine food chains
• Only about 10% of energy is transferred between trophic levels
• More efficient to feed at lower trophic levels
  • Large mammals more efficient
  • Ectotherms more efficient

Biomagnification

• Biomagnification occurs when molecules concentrate at higher trophic levels
• Bioaccumulation occurs when molecules accumulate over time

Nutrient Cycles

• Biogeochemical cycles are the paths elements take from abiotic

systems to producers, consumers, decomposers, and back

• Rate controlled by many factors
  • Oxygen availability
  • Temperature
  • Precipitation
  • Detritus quality
  • Detritovore abundance, diversity