Unit 3 - Ecology

Species

A group of organisms that share common characteristics and that can interbreed to produce fertile offspring.

Classifications

The organization of organisms into different taxa or groups.

Binomial name

Has two parts. The first word is the genus such as Camponotus, whereas the second part is the species name like maculatus. This needs to be written in italics or underlined.

Classification of Homo sapiens

Domain

Eukarya

Kingdom

Animalia

Phylum

Chordata

Class

Mammalia

Order

Primates

Family

Hominidae

Genus

Homo

Species

Sapiens

Dichotomous keys

It is a serious of questions based on the physical characteristics (phenotype) of the organisms concerned.

Cladogram

Clades are the evolutionary relationships and a cladogram shows a hypothesis of the evolutionary relationships between members of a taxon.

Population

A group of organisms living in the same area at the same time, and which are capable of interbreeding.

Abiotic vs biotic factors

Abiotic factors are non living things such as PH, salinity and temperature that many influence an organism or ecosystem. Biotic factors are living things/biological factor that may impact an organism or ecosystem such as predation, parasitism and disease.

Niche

The ecological role of a species in an ecosystem and the range of conditions necessary for it’s survival. It depends not only on where it lives but also on what it does.

Fundamental niche vs realized niche

Fundamental niche is the set of all abiotic and biotic factors and resources in which a species or population could theoretically survive and reproduce. A realized niche is the actual conditions and resources a species or population could exist due to abiotic factors and competition.

Predation

It is when one organism acts as the predator and feeds on another organisms called the prey. This may not seem good for the prey, but it creates a negative feedback loop and ensures the stability of the ecosystem.

Commensalism

An interaction between two species where one benefits and the other is not harmed or benefited. Example: Remora fish and sharks.

Herbivory

It is when organisms, usually animals feed on plants. The organisms eating the plants are called herbivores.

Parasitism

It is a interaction between two organisms, where one organism gets resources it needs from the other organism, the host, but may harm the host in the process.

Mutualism

It is a interaction between organism where both benefits and neither suffers. One example when ants farm aphids to get the honeydew.

Disease

Disease is a departure from the normal state of functioning of any living organism and is marked by symptoms of illness.

Competition

It is when organisms compete for limited resources such as food, water, mates etc.

Carrying capacity

The maximum population size of species that can sustainably be supported.

Limiting factors

A resource in the environment that can significantly affect a population’s size if it becomes limited.

• Plants - nutrients, food, water

• Animals - space, food, mate, shelter

Density independent factors

Limiting factors that do not depend on the size of the population and affect every population in the ecosystem, they tend to be abiotic.
Examples:

• Natural disaster: Flooding, fires

Density dependent factors

Limiting factors that are related to population density. They are usually biotic (like competition) that limit population growth.

There is usually an increase of predation and spread of pathogens in dense populations. Density dependent/independent factors are examples of negative feedback.

Population growth curve: J curve

First when there are no limiting factors the population or an activity grows extremely quickly, but as soon as the population reaches the carrying capacity, the population crashes. Example: bacteria and reindeer on St Matthew Island

Population growth curve: S curve (logistic growth)

Shows the population or an activity grow exponentially, but then slowing growth as the carrying capacity is reached.

R strategists vs K strategists

R strategists produce a large number of offspring with minimal parental care. They grow quickly and have a short lifespan. Examples include rabbits and insects. K strategists produce fewer offspring with more parental care and they tend to have a longer lifespan. Examples include mammals such as elephant and whales.

Quadrant sampling

Sampling for non motile or slow organisms. A square frame is used to describe the area, enabling the extrapolation to a bigger area. An area is chosen, length and width.

Estimated population size: Multiply the mean number of organisms in 1 quadrant by the number of quadrants that would fit into the field.

Capture mark release recapture

1. Capture: In your area of study, capture as many of the study animals as possible in a fixed time period. Record the number that you have caught.

1. Mark: Mark the captured organisms in a way that does not harm them or make them more or less prone to predation.

2. Release: Release the animals back into their environment and give them sufficient time to reintegrate into the population. Fast moving animals like mice will reintegrate more quickly than slow-moving animals like snails.

3. Recapture: Capture a second sample of the population using the same fixed time period used for the first capture. Record the total number of animals that you have caught in the second sample. Include the number of marked animals. You can now estimate the size of the population.
   
   Lincoln index formula: (Number of animals capture on first day x number of animals recaptured in the second day) / number of marked animals in the sample recaptured on the same day.

Benefits:

• Can be applied to a wide range of species

• Can be used to collect long term data

Limitations:

• May not be ethical

• Can harm the animal

Community

A group of interacting populations of different species living within an ecosystem.

Habitat

It is the location in which a community, species, population or a organism lives.

Keystone species

A single species in an ecosystem that maintains its structure and function. Examples include sea otters, wolves, elephants and purple sea stars.

Tipping points and new equilibria

They lead to the collapse of the original ecosystem and the development of a new equilibrium. One example is the deforestation of the Amazon.

Zonation

The arrangement or pattering of communities or ecosystems in response to change, over a distance, in some environmental factor.

Example: Intertidal zone and barnacles. Some barnacles less air exposure while some like more.

Ecological succession

The long-term change in the composition of a community

Primary succession

Pioneer species: A piece of land without any living organisms (biotic factors), —> pioneer species —> lichens, —> small plants and lichens, grasses and perennials . Intermediate species: shrubs, grasses, pines

Secondary sucession

A fire or anything else destroys everything (natural phenomenon.) Then the same process as primary succession takes place. But pioneer species process is usually quicker because there may already be seeds in the soil.

Things threatening biodiversity

• Habitat loss

• Invasive species - example: Yellow crazy ant

• Over harvesting and hunting

• Pollution

Factors determining conservation size

1. Population size - low population size or reduced

2. # of matured individuals

3. Geographic range & degree of fragmentation

4. Quality of habitat

5. Probability of extinction

IUCN redlist

Determines how vulnerable a species is, global conservation status of species

Why biodiversity is crucial?

Direct service

• Shelter

• Food, genetic diversity

• Medicine

Indirect service

• Removal of chemicals, wetlands

Aesthetic and ethical

• Value, what is left for the future

Types of conservation

Ex citu conservation

• Botanic gardens

• Zoo

• Seed banks

• Strategies outside natural habitat

In citu conservation

• National parks

• Reserves and sanctuaries

• Strategies inside natural habitats
  
  In citu conservation is conserving organisms in their natural habitat. Protects ecosystem and habitat. Whereas in ex situ conservation is conserving organisms in man made habitats. Protects individual species and genetic information.

Designing protected areas

• Area

• Edge effect

• Shape

• Corridor

• Buffer zone
  
  Large vs small protected areas
  Large areas: Can be beneficial because some species can only survive in larger areas and it reduces the edge effect.
  
  Smaller but multiple areas: Increases the edge effect. However, some species thrive better such as birds.

Biosphere

The thin outer layer of earth which is inhabited by living organisms. A biosphere represents the parts of the Earth where life exists.

Biome

A collection of ecosystems sharing similar climatic conditions.

Ecosystem

An area where a community of organisms live and interact with their environment.

Simpsons reciprocal index

Richness: diversity of species, number of unique species

Evenness: How evenly the individuals with each species are distributed

Types of biodiversity

Habitat diversity: Variety of different ecosystems or habitats within a specific area.

Species diversity: Number and variety of species within a given habitat or ecosystem.

Genetic diversity: The variety of genetic traits and characteristics within a population or species.

Resilience

It is an ecosystems ability to recover when disturbed. Biodiversity increases resilience because if one species disappears, then another species with a similar niche can replace it.

Biodiversity hotspots

• 1500 endemic plant species

• More than 70 % of the habitat already lost

• Distinct environmental conditions

Example: Galapagos islands

Biodiversity areas

Indigenous approachment to land management

Key biodiversity areas (KBAs)

Tensions: Conflict between exploitation, sustainable development and conservation.

Environmental justice

Kraeng Krachan National Park

Transect sampling

The sampling method in which you collect data (counting) along a transect (a line, path, or strip along a habitat). Can be used to record the change over time.

Invasive species

An invasive species is a non-native species that threatens its new ecosystem. Non-native species are usually brought to new ecosystems through human transport and trade.

Arguments for habitat and species preservation

Aesthetics: focuses on the beauty and visual appeal (from a human perspective)

Ecological: Focuses on the vital ecosystem services provided by diverse species

Ethical: Moral responsibility to protect and preserve the diversity of life on Earth.

Sociocultural: Importance of biodiversity in providing for human social wellbeing.

Conservation strategies from different perspectives

Ecocentrism: this assigns intrinsic value to biodiversity, treating ecosystems and species as inherently valuable components in sustaining all life on Earth. Low intervention and in situ conservation strategies

Anthropocentrism and technocentrism: viewed primarily through the instrumental value of biodiversity for humans. Strategies include eco tourism, gene banks and establishing zoos.

Benefits of rewilding

Benefits

• Ecosystem resilience

• Ecosystem services

• Economic benefits

• Socio cultural benefits

Limitations of rewilding

• Limited scope and slow results

• Uncertainty

• Resources (can require a lot of resources)

• Land use conflict with other people like farmers

Data logging

Capturing, storing, measurements, such as temperature, humidity, pressure, over time using sensors and electronic devices.

Ecosystem

The community and physical ecosystem with which it interacts. Tropical rain forests are examples of old ecosystems.

Human activities leading to tipping points

Tipping points can lead to collapse of the original ecosystem and development of new equilibrium. One example of this is deforestation of Amazon rainforest, reduces generation of water through transpiration, thus reduces cooling and precipitation necessary for the maintenance of the remaining forest.

Climate vs weather

Climate describes atmospheric conditions over relatively long periods of time, whereas weather describes the conditions in the atmosphere over a short period of time.

Gross productivity

Total amount rate at which producers/plant algae capture energy and convert it into chemical energy.

Net primary productivity,

Remaining energy stored as biomass after plants use that energy for respiration.

IUCN

Species that has become extinct: Dodo bird

Species that is critically endangered: Sumatran tiger

Species whose conservation status has been improved by intervention: Siberian tiger

Key biodiversity areas/hotspots

Sites that contribute significantly to the global persistence of biodiversity.

Tension between indigenous people and national parks

Examples: Maasai in Serengeti park and Karen people in Kaeng Krachan national park.

Examples of rewilding

Rewilding in Gorongosa national park, Mozambique. Reintroduction of wolves to Yellowstone national park.

Succession of conservation or regeneration measures needs to be assessed

Conservation measures have successfully protected biodiversity, and consider the impact of the measures on local communities.

Can be evaluated at three levels

1. Did the measures in the project succeed as planned

2. Was the project well received by the communities impacted?

3. Was this the best way to conserve nature

Case study: Wangari Maathai’s Kenyan Green Belt Movement

Established in Kenya. Focuses on empowering women. Facilitated the planting of over 51 million trees to combat deforestation, soil erosion and climate change. Focuses on establishing tree nurseries, plant trees on their farms, at schools, and in communities, promoting sustainable livelihoods.

Wildlife friends foundation

Example of rehabilitation and refuge for animals in need.

Positive feedback loop/negative feedback loop

An initial change in a system is amplified, causing the output to reinforce and amplify the original cause.
Self regulating biological and ecological process that counters a change to bring a system back to a stable point

Donut economics

Social needs inside and environmental outside. Focuses on sustainability and well being. Case study: Bangkok, Thailand. Has the biggest green roof. Has theater, meditation centers. There is park in Chulalongkorn University designed with incline so that all of the water is absorbed by the ground. Instead of concrete that is non permeable, soil allows water to be absorbed into ground, preventing flooding.

Conditions required for coral reef formation

Example of marine system. Factors include: water depth, pH, salinity, clarity and temperature.

Obligate anaerobes, facultative anaerobes and obligate aerobes

Obligate Aerobes: Require oxygen to survive

Facultative Anaerobes: Can grow with or without oxygen

Obligate anaerobes: Cannot live or grow in the presence of molecular oxygen

Archaea

One of the three domains of life. They are varied in how they obtain energy for ATP production.

Phototrophy: They capture sunlight without using chlorophyll.

Lithotrophy: Oxidising organic molecules.

Organotrophy: Break down ready made organic molecules.

Saprotrophs

Use external digestion, secretes enzymes that break down nutrients externally and then they absorb the nutrients.

It is heterotrophic nutrition and this mode can be referred to as decomposers.

Different types of troph

Photoautotroph

Saprotroph:

Autotroph:

Chemotroph: Obtains nutrients by breaking down chemical compounds

Heterotroph: Obtains nutrients by breaking down organic compounds.

Chemotrophic nutrition

Most archaea carry out chemotrophic nutrition and gain their energy and nutrients by breaking down or metaboliing molecules from their environment such as hydrogen sulfide and ammonia.

Keeling curve

Daily record of global atmospheric carbon dioxide concentration that tracks humanities impact on Earths climate. Carbon dioxide drops in summer as plants absorb carbon dioxide via photosynthesis, rises in fall and winter as plants decompose.

Ecosystem

A community of living organisms interacting with each other and their physical environment.

Bioaccumulation vs biomagnification

Bioaccumulation is the buildup of toxic substance in an single organism over time, while biomagnifcation is the increase in concentration of that substance as it moves up the food chain. One example of biomagnifcation is mercury and DDT.