Ecology Flashcards
What is ecology?
The study of interactions that determine the distribution and abundance of organisms
Fundamental ecological questions
- Where do we find organisms (why are they there and how many?)
- What are they doing there? (Their role and what keeps them there)
- How is that they are a success in that environment (why they have fitness)
Patterns of distribution (3)
Random
Regular
Clumped
Random distribution
Randomised, neutral interaction between individuals and between individuals and local environment
Regular distribution
Very organised, evenly spaced, less common
Clumped
grouped, usually occurs when resources are concentrated in smaller areas
What is biogeography?
the study of the patterns of geographic distribution of organisms and the factors that determine those patterns
Main resources that are used
Light and temperature light
Water (H2O)
Air (Co2 and O2)
K, Na, S, Mg all of these electrolytes and protiens
Macroclimate
Patterns on the global ecosystem and landscape levels
Microclimate
Finer scale patterns such as a community of organisms on a tree trunk
Major components of climate
Temperature
Sunlight
Wind
Precipitation
Physical Principles
- Hot air carries more water than cold air
- Hot air moves up and cold air moves down
- Hopkins’ bioclimatic law: air cools as it rises
- Coriolis effect: longitudinal movement on a rotating object results in apparent latitudinal drift
What is Hopkins’ Bioclimatic Law
Air cools as it rises
What is the Coriolis effect?
Longitudinal movement on a rotating object results in apparent latitudinal drift
- It is warmer closer to the equator (due to sunshine acting directly)
Rain shadows (what causes it)
Region that has little rainfall because it is sheltered by hills/mountains
What is Primary Production
The conversion of energy (usually light) into chemical energy that is stored in organic compounds in biota (living organisms)
What does photosynthesis mainly produce
Sugars
What does the availability of biochemical energy (ATP) depend on?
Air, water and sunlight
What are limits to primary production
On land, water, sunlight and temperatures are the main limits to production
In deep aquatic environments, water is everywhere, but light is rarely found together with nutrients
Primary production equation
Net production = Gross production - Respiration
What is gross production
Everything that a plant has put into their growth- cellular respiration (all in terms of energy)
What is another word for food chain
Trophic level
What is production efficiency? (as well as other factors in ecological efficiency)
A percentage of energy from a food source that is used for growth and reproduction
Waste- unassimilated energy
Growth- energy assimilated as biomass/reproduction
Cellular respiration- energy used to maintain life
What does ecological efficiency determine?
Abundance
What is a primary consumer?
A herbivore
What is Biomass?
Renewable organic material that comes from plans and animals
What is bioaccumulation?
A buildup of an absorbed chemical in an organism overtime
What is biomagnification?
Increase in the concentration of the chemicals in each organism up the food chain
What is the Island Equilibrium Theory
Species diversity on islands will represent a dynamic balance between the probability of successful colonisation by new immigrant species, and extinction of existing resident species
What is Wallace’s line?
An imaginary line that goes in between Australia and Bali that shows the difference in animal species and is termed island biogeography
- There is a part where extinction number is = with immigration numbers
What do interactions drive
Diversity
What is biodiversity defined as?
the number of species present
Evolutionary consequences of competitive interactions
only one species becomes extinct
division of niche takes place (or resource partitioning)
Source population
Population that is well established and produces lots of individuals who might immigrate to another place but is still strong
Sink Population
Population that may not have as stable characteristics, most likely to be found on an island with competitive problems and they go extinct on the island, but the source is still producing them
Niche (what and the two types)
Niche: the role an organism plays in its environment
Fundamental niche and Realised niche are the two
Fundamental Niche
The possible distribution of the organism as determined by its evolutionary history
- e.g. all humans can theoretically live in Antartica but we all don’t
Realised Niche
The actual distribution of the organism
- i.e. there are actually not many people who live in Antartica, the realised niche is that we live in Australia
Specialist
Specialists are ecologically more efficient than generalists at the cost of having a more restricted fundamental niche
Specialists will out compete generalists
May be efficient in the environment that they are in but if it is disrupted then they may struggle
Less resilient to change
Generalist
More general adaptation and therefore can thrive in more environments
Competitive exclusion
two species competing for the same resources cannot stably coexist if other ecological factors are constant.
Disturbances examples
- Deforestation
- Agricultural development
- pollution
- Climate Change
- Invasive species introduced
- Natural Disasters
Different type of disturbances
None, Maximal, Intermediate
What does no disturbance mean
No disturbance: species well adapted, can take over area
What does maximal disturbance mean
Maximal disturbance: Species dies, vulnerable to being obliterated if disturbance is big enough. An extreme
What is intermediate disturbance
Intermediate disturbance: somewhere in the middle, don’t want disturbance to be too extreme
What is the intermediate disturbance hypothesis
Diversity will be the highest when disturbance prevents competitive exclusion, but is of low enough intensity to allow many species to prosper
Keystone species
Have the largest number of interactions within an ecosystem
NOT always at the top of the food chain
ALL ABOUT INTERACTIONS
Red queen hypothesis
” It takes all the running you can do to stay in the same place”
Never stops, one thing will keep pushing the next (e.g. fast cheetah will push a more nimble deer and so on)
Symbiosis (Types)
Parasitism (e.g. tick) +/-
Mutualism +/+ ( e.g. clownfish and anemones)
Commensalism +/0 (e.g. bird on a bison)
What are the parameters that the size of a population is dependant on?
Sources of increase:
- Birth
- Immigration (in)
Sources of decrease
- Death
- Emigration (out)
Growth Rate (r) (formula and what r means)
Determined by birth rates (b) and mortality rates (m)
= B - m = r
if r = 0 : no growth in the population
if r> 0: population increase
if r<0: population decreases
Population growth
Intrinsic rate of growth (rmax) is the rate of growth with no limiting factors
- R max is characteristic of the species
Change in population (formula)
Number of births (b) - Number of deaths (d)
n = population size
t = time
delta = change in/over
delta n / delta t = b-d
Exponential Growth formula
dN/dt = rmaxN
rmax = intrinsic rate of growth
What factors prevent exponential growth
Availability of resources
- food
- nesting
- water
What does ‘K’ mean
Carrying Capacity of the environment
Logistic growth
dN/dt=rmaxN*(KN/K
When N is smaller in value to K per capita growth approaches 1 (high rate)
When N is large and resources are limiting, r max approaches - (low rate)
Density independent
When abundance is low e.g. rapid reproduction
Density dependant
When abundance is approaching the carrying capacity (K)
Life history traits reflect evolutionary adaptations of:
- Reproduction strategies
- Number of offspring
- Level of investment
- Age of sexual maturity
- Age specific distribution of reproduction and mortality
What are the three types of survivorship
Type 3 survival: mortality decelerates over typical life span
Type 2: mostly constant mortality rate
Type 1: mortality accelerates with age
True or false: you can put all of your resources into both reproduction and growth at the same time as it will benefit productivity and fitness
FALSE you cannot do this as reproduction has consequences and costs
