Studied by 49 people
Types of prokaryotes
Bacteria and archaea
How prokaryotes differ from eukaryotes
Prokaryotes are single celled, they may stick together to form associations and biofilms, generally much smaller than eukaryotes, chromosome is single circular double stranded DNA, exchange genetic material extensively
Prokaryotes
The oldest, structurally simplest, and most abundant forms of life
Differences between bacteria and archaea
Different lipids in plasma membranes, different molecules for support in cell walls, archaea are more similar to eukaryotes in DNA replication and gene expression
Bacteria and archaea
Can be autotroph or heterotroph
Extremophiles
Organisms that can survive in extreme environments such as extreme temperature, pressure, and salinity
Biological importance of prokaryotes
Abundant, diverse habitats, base of some food webs
Examples of extreme environments
Morning glory pool (hot spring) and the Dead Sea (hypersaline)
Koch’s germ theory
The microorganism must be present in every case of the disease and absent from healthy individuals, the putative causative agent must be isolated and grown in pure culture, the same disease must result when the cultured microorganism is used to infect a healthy host, the same microorganism must be isolated again from the diseased host
Virulence
Ability to cause disease, heritable variable trait
Crowding and poor sanitation
What leads to an increase in virulence
E. Coli
Example of a species with both virulent and harmless strains of bacteria
Microbiome
Community of microbes that naturally inhabit body or parts of the body
Bioremediation
Living organisms (ex. bacteria) are used to decontaminate affected areas
Example of bioremediation
Some species of bacteria are able to solubilize and degrade oil from spills on beaches
Protists
Cannot be classified as plants, animals or fungi
Why protists are important primary producers
They provide food for a large proportion of aquatic species
Life cycles of protists
Most are free-living, some are parasitic, asexual reproduction is common, sexual reproduction may occur when conditions deteriorate
Ecological importance of protists
Produce oxygen, producers in freshwater and saltwater ecosystems, major component of plankton, many are symbionts
Examples of mutualism
Coral reefs and photosynthetic protists in tissues of corals (animals) or termites and parabasalids
Malaria
One of the world’s worst chronic infectious diseases caused by five species of parasitic protist
Fungi
Eukaryotes that grow as single-cell or large, branching networks of multicellular filaments, absorb nutrients from dead organisms, and are the world’s most important decomposers
Common ancestor
Fungi and animals share
Characteristics of fungi
Heterotrophic, cells release digestive enzymes and then absorb resultant nutrient molecules, most are saprobes, some are parasitic, several in mutualistic relationships with other organisms
Important economic and ecological impacts of fungi
Antibiotics were discovered, fungi live in close association with plant roots and provide nutrients for the plant, and the carbon cycle was accelerated
Saporophyte
Fungi that digest dead plant material, help cycle carbons through terrestrial systems
Carbon cycle components
Fixation on carbon by land plants, and release carbon dioxide from cellular respiration
Population
Consists of all individuals of the same species living within a specific area, can fluctuate based on changes in the environment, natural disasters, and competition between species
Distribution
A geographic range which has been influenced by biotic and abiotic factors
Uniform distribution
Individuals are equally spread apart
Example of uniform distribution
Territorial birds (penguins)
Random distribution
Individuals are spaced at unpredictable distances from each other
Example of random distribution
Plants with wind dispersed seeds (dandelions)
Clumped distribution
Occurs when individuals form social groups or resources are in small areas
Example of clumped distribution
Elephants traveling together
Sessile and mobile
Types of sampling methods
Examples of sessile sampling methods
Quadrants and line transects
Example of mobile sampling method
Mark and recapture
How mark and recapture works
percent marked is equal to average percent marked “recaptured”, individuals don’t move in or out of study area, individuals mix between captures, no capture bias, individuals do not learn to avoid capture, individuals do not change behavior because of being captured
Demography and life history
Depends on births, deaths, immigration, and emigration
Populations grow
Due to births and immigration
Populations decline
Due to deaths and emigration
Immigration
Occurs when individuals enter a population by moving from another population
Emigration
Occurs when individuals leave a population to join another population
Survivorship curves
Show the distribution of individuals in a population according to age
Fitness trade-offs
Every individual has a restricted amount of time and energy at its disposal, its resources are limited
High fecundity (r selected)
Tend to grow quickly, reach sexual maturity at a young age, and produce many small eggs or seeds
High survivorship (k selected)
Tend to grow slowly, invest their energy and time in traits that reduce damage from enemies, and increase their own ability to compete for resources
Exponential and logistical
Types of population growth
Exponential growth
Not dependent on population size (density independent) rare in real world, colonization of a new habitat, recovery after disaster
Logistical growth
Dependent on population size
Carrying capacity
The number of people or other living organisms that the environment can support with limited resources
Limiting factors
Density dependent and independent
Example of density independent factors
Limiting resources (food, space, etc)
Example of population crashes
reindeer population decreased due to over foraging of food supplies
Population cycle
Usually exhibits predator-prey dynamics and how they change over time
Metapopulations
Patches of habitat are linked by immigration/emigration sources and sinks, useful model for conservation biology
Behavior
Response to a stimulus
Foraging behavior
What, how and when to eat
Optimal foraging
Balancing of costs and benefits
Mating systems
Monogamy, polygamy, promiscuity
Monogamy
One female mates with one male, forming a pair bond (common in birds)
Polygamy
One male mates with two or more females, often occurs in situations where a male defends a territory of resources
Promiscuity
Males and females each have two or more sexual partners; some females choose multiple mates while others are coerced
How animals navigate
Piloting, compass orientation, and true navigation
Piloting
The use of familiar landmarks
Compass orientation
Movement oriented in a specific direction
True navigation
The ability to locate a specific place on Earth’s surface
Example of navigation
Sea turtles using magnetic map orientation
Migration
The long-distance movement of a population associated with a change in seasons
Communication
The type of signal used by an organism correlates with its habitat
Forms of communication
Singing, threatening gestures, language, bees’ waggle dance
Altruism
Behavior that has a fitness cost to the individual exhibiting it and a fitness benefit to the recipient
Hamilton’s rule
Altruistic behavior is most likely met when the fitness benefits of altruistic behavior are high for the recipient, the altruist and recipient are close relatives, and the fitness costs to the altruist are low
Coefficient of relatedness
The mean numbers of genes shared between two individuals
Direct fitness
Derived from an individuals own offspring
Indirect fitness
Derived from helping relatives produce more offspring than they could produce on their own
Ecology
The study of how organisms interact with each other and their environment
Levels of ecological study
Organismal, population, community, ecosystem, global
Conservation biology
The effort to study preserve and restore threatened populations, communities and ecosystems
Biotic factors
Living factors related to organisms that limits distribution
Abiotic factors
Non-living factors that that limit distribution
Niche models
Show the range of conditions tolerated by a species
Climate patterns
Climate is the long term weather conditions found in the area
Average temperature and precipitation
Influences amount of biomass generated
Aquatic biomes
Lakes, streams, rivers, ocean
Salinity
The proportion of solutes dissolved in water
Water depth and sunlight
The ocean is divided into different zones depending on
Types of nutrient availability
Coastal runoff, ocean upwelling, lake turnover
Commensalism
Association between organisms where one benefits and the other is not benefited or harmed
Interspecific competition
Members of different species use the same limiting resources
Intraspecific competition
Occurs between the same species
Competition
Lowers fitness of both individuals involved
Niche overlap
The degree to which species share the factors regulating population growth
Fundamental vs. realized niche
Theoretical range vs. proportion actually occupied
Consumption
An agent of natural selection
Evolutionary arms race
A repeating cycle of reciprocal adaptation
Inducible defenses
Defensive trait in response to the presence of a consumer
Mimicry
A harmless species mimics the coloration of a harmful species
Consecutive defenses
Camouflage, aposematic coloration
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