Module 4 Flashcards
What is biodiversity
It refers to the full range of organisms on earth and their interactions
Why is biodiversity good for us (benefits of biodiversity)
Having a good biodiversity enables a healthy ecosystem. Healthy ecosystems allow for a lot of benefits
Biodiversity is key for human survival, wellbeing and economic propserity
They provide:
Sources of food
Drug derivations
Water
Pollination
Pest and disease control
Recreational Use
Cultural Significance
Rat material provision
Soil fertility
Nutrient cycling
What % of Aus is for grazing in modified pastures and cropping
13%
What is the order of crop production area in a decreasing order
Wheat, barley, canola, cotton, sugar cane
What is the order of livestock numbers in a decreasing order
Poultry, sheep, cattle
What are ecosystems
Ecosystems are communities of living organisms (plants, animals, and microorganisms) interacting with one another and with their physical environment (such as air, water, and soil). This interaction forms a complex network of energy flow and nutrient cycling that sustains life within a given area.
(typically includes a biotic and abiotic factor)
Why are our ecosystems good for us
They are the basis of life - they provide habitat, promote food chains and webs, and control ecological cycles and processes
Explore Australia’s biodiversity
320 500 invertebrate species
25000 vascular plant species
243 frog species
750 000 fungi species
5000 nonvascular plant species
830 bird species
390 mammal species
950 reptile species
160 000 single - celled species
5000 fish species
What has been the trend in Aus’s biodiversity?
It has been threatened in the past decades, and there is an increased number of animals considered endangered
What conservation responses would allow Aus threatened species to benefit from the most
Prevention of habitat loss
Getting rid of invasive species
Control of fires
Mitigating climate change
Manging pollution
Preventing overexploitation
What is natural capital
This is the world’s stocks of natural assets - resources and ecosystems which provide humans w/ essential g+s
Explain the case study on the Victorian highlands
Basically in the Vic highlands, the Headbeater’s possumw as under threat due to logging, causing them to be listed as endangered
Logging in Vic highlands thus poses a massive risk to habitat loss of other species as well. Logging here is normally to sell the timber
However, money gained fro harvesting timber is actually significantly outweighed by other industries –> if this is the case, then why do we continue doing it?
As a result, we need to think holisitcally on nature-based solutions and diverse teams needed to make progress on habitat destruction
What is the function of the System of Aus Environmental Economic Accounts (SEEA)
Takes human inputs, productions and benefits and same ecosystem services into account when calculating the GDP
What are ecologists meant to do for the earth
Act as ‘doctors’ for the earth
They record observations in biodiviersity –> diagnose problems, manage risk and monitor change –> prescribe a treamtnet/remediation and restoration for the problem –> advocate for ecosystem health
What was Scientists’ warning to humanity in 2017
There is a decrease in freshwater resources, increased co2 emissions and temp changes, increased population, decreased forest area and vertebrate species abundance
What was Scientists’ warning to humanity in 2021
Increased population, increased energy consumption, decreased ice mass, increased GHG emissions and CO2 emissions
What is ecosystem collapse
Basically when disruption of ecosystems lead to irreversible collapse of the ecosystem, especially if defining features and functions of ecosystem are lost
How many AUs ecosystems have been reported to show signs of collapse
19
What are some collapse pofiles (explain whta they look like)
Abrupt (immedaite drop in population)
Stepped (gradual ‘step-like’ drops in population)
Fluctuations (constant jumps and drops in eco population)
Smooth (gradual decrease like an exponential curve)
What are ‘presses’ in ecosystem collapse
These are gradual/ongoing changes in enviro which cause ecosystem collapse
What are ‘pulses’ in ecosystem collapse
These are sudden changes in enviro which cause ecosystem collapse
What is morphology
This refers to the physical structure of an organism including shape, size and anatomical features
How can morphology influence behaviour? Give examples.
These physical traits are normally influencing or adapted to specific behaviours and physiological processes
I.e. streamlined body of a fish allows for the behaviour of swimmin
The ability to have wings allow for the behaviour of flying
Carnivores have different gut floras –> causes them to want to consume meat
What is physiology
Refers to the internal biological processes that keeps an animal alive, such as metabolism, respiration etc
How can physiology influence behaviour? Give examples.
The presence of fast twitch muscle fibres in cheetahs allow them to have a predatory behaviour when it comes to hunting animals
What is behaviour
Behaviour is an action or reaction of animals in response to various stimuli, and is normally shaped by the animals’ morphology and physiology
Give an example of behaviour
Being able to fly, or predators stalking prey (enabled by morpholpogical trait of sharp claws or physiological trait of fast reflexes)
What is coping mechanism composed of
Coping mechanism = behaviour + morphology + physiology
How can behaviour be related to the abiotic environment?
Behaviour might be in response to the abiotic environment
For example, a lizard might try cooling its feet on a hot desert sand by constantly alternating which feet they lift up –> drives behaviour of lifting feet etc
How can behaviour be related to a biotic environment
Behaviour might be in response to other organisms
I.e. being scared of being hunted –> hiding/escaping/defending/foraging etc
What is fitness
Fitness refers to an animals ability to reproduce or contribute to the genepool of offsprings
An individuals relative contribution to the next generations gene pool
Can behaviour affect fitness? What experiment?
Insect herbivores consume vegatitive parts of plants (e.g. leaves)
Insects pollinate ~2/3 of all plants, often w/ food reward (e.g. nectar
Does eating diff quality resources influence fitness?
Does food quality affec butterfly reproductive success? –> foraging on high quality food has a fitness advantage?
What did the experiment on behaviour and fitness find?
There is no significant impact of adult nectar quality on no. of eggs laid, however there was a significant impact of larval diet quality on the no. of eggs laid
Thus, concluded that behaviour affects fitness, together w/ morphology and physiology. Thus, many behaviours are adaptive
What is the ecological significance of behaviour
Behaviour acts as a link between individuals and their environment
Behaviour affects demographics (population level etc)
Affects interactions between diff species
What is the evolutionary significance of behaviour
Behaviour has some genetic basis (nature vs nurture)
Behaviour affects fitness
Behaviour can be selected when benefits > costs
Explain how animals may try to obtain their food
Ambush predators ( good camouflage to catch food)
Active predators (agile and quick –> easier to catch food)
What influences animals foraging strategies
What they eat
Diet breadth (specialist –> generalist)
How they get the food (ambush vs active)
Foragining strategies AREN’T RANDOM A
What is the Optimal Foraging Theory
Suggests that an animal wants to maximise their rate of food intake
But, they must make trade offs when deciding how and where to forage. Trade offs include energy expenditure, time, predation risk and food availability
What is the Giving Up Density
This refers to the remaining quantity of food when a forager will decide to leave a food patch
What is the Marginal value theorem
This is where animals decide when to leave a resource patch and move to another to optimise their foraging efficiency
Modelled when to leave a food patch in a depleting environment, and predicts that foragers should leave a food patch when capture/harvest rate of a patch is less than the average capture/harvest rate of all of the patches
What are some anti-predator strategies?
Staying in a group
Acting costly
Be costly
Stick to foraging in known/safe areas
Hide
Run away
What are some costs to the anti predator strategies
Group –> more competition for existing food
Feeding near safe places –> missed opportunities for potentially more plentiful feeding places
Is reproductive behaviour random?
No
What are the two main behaviours relevant to sexual reproduction
Male-male competition
Female choice (sexual selection)
What are the two types of sexual selection
Intrasexual selection
Intersexual selection
What is intrasexual selection
This refers to male-male competition
What is intersexual selection
Refers to mate choice (often by the female)
Why do peacocks have fancy tails?
It is confusing because they do have high costs of maintaining the tail, but the benefit is that it increases access to mate, which is ultimately good
Explain the benefits and costs of parental care
Benefits = increased survival and growth of offspring = greater fitness
Costs = missed opportunities (i.e. less food)
Justify why behaviour isn’t something only animals do
Slime moulds normally move to more nutrient-dense environments, even though they arent animals and dont have brains
Plants have diff behaviours at different times as well (leaves and stems grow towards light, and the roots grow along chemical gradients)
What is a group
A group refers to multiple organisms who may be of same or different species occupying a common space. However, they don’t necessarily have to be interacting with one another
What is a population
A population refers to a number of organisms of the same species occupying a common space/geographical region.
Populations could move around
Why is knowing about populations important (importrance of population biology)
Form understanding of ecology, evolution, conservation and management
Understand temporal dynamics of populations (how they change over time), understand spatial dynamics of populations (where are these populations across Aus), looking at how populations are limited by spatial and temporal distributions to help us understand them a bit more
Explain variables affecting changes in population size
Births
Deaths
immigration (coming in)
Emigration (going out)
Growth
Age of maturity
Sex ratio
What are the conditions of population growth in closed systems
Only affected by births and deaths
Population growth = change in no. of individuals over time
WHat is the formula for popuulation growth in closed systems
Nt+1 = Nt + Births - deaths
Explain the role of birth and death rates in determining population growth
Fundamental to population growth. Births are additions to populations whereas deaths result in drops in population
What is exponential growth
Populations grow faster as they get bigger
What are the different dynamics of population growth
Discrete, continuous
What is discrete population growth? Why does it occur?
Reproduction occurs periodically (i.e. only spring) –> population graph looks disjointed, goes up and then drops and then repeats but overall up
What is continuous population growth? Why does it occur?
It is a smooth curve up or down or straight. Occurs because reproduction might occur year round
Why do we rarely see exponential growth? What do we see instead?
We see a logistic curve. this is because often population growth is resource limited –> can’t keep growing such as that of an exponential growth
What is the carrying capacity
The maximum population an environment has the ability to provide for (considering enviro restrictions) 0 growth stops at carrying capacity
How can we estimate birth rate
Histology of reproductive organs
Capture/counting of fertilised gametes
Counting of newly born individuals
How can we estimate death rates
Challenging as we can’t know if an animal is dead unless we see it appen or sample entire population. Common methods:
Tagging - check o how many of the tagged are alive and then assume
What are the variables at play for population growth in open systems
Influenced by birth, death, immigrants, emigrants
How can we estimate population growth in open systems
Tagging and recapture (physical, acoustic, gps, radiotelemetry), genetics, can also use citizen science
Explain how mark-release-recapture works
MRR estimates total population using sample proportions
Assumes various things: closed population (no immigration/emigration), all individuals equally likely to be marked, marked individuals don’t lose their mark
Explain the formula for mark-release-recapture
Number marked / population size = number of marked recaptures / number of recaptures total
rearrange
WHat is a spatially structured model
model used to study enviro systems that incorporate effects of spatial variation and organisation –> takes into acount that interactions, movement, processes vary depend on geographical / spatial arragnement rather than an even spread approoach
Metapopulations are local populations but individuals move, and demographics vary spatially
How can we estimate growth and age of animals or plants
Trees - tree rings
Perennial plants - rings in tap roots
Mammals - teeth
Fish - otoliths (rings in teeth and teeth wear)
What is an age/stage model
Involves treating all members of a population with regard to their age and stage of life (especially as that influences their fecundity and survival)
Life tables show survivorship probability at each age. Long term studies is jet to understanding population dynamics
Involves splitting populations into different age groups / stages and seeing the spread
WHat are the principles of a Population Viability Analysis? WHat does it aim to do/model
PVA is a tool to model population dynamics over time, and uses basic population data. It allows us to model:
How changes to ecosystem will affect % of popultion surviving, how these changes interact w/ one another, and how the changes ineract during one or many bad years (e.g drought)
Ultimately allows to predict population dynamics in the future, and predict impact of changes in enviro
What is the key info required for a population viability analysis
Population size/ carrying capacity
Fecundity (% of giving birth)
Mortality
Inter-annual variation in parameters
What is extinction
The loss of all populations of a species
What could result in extinction
Genetic stochasticity (small populations)
Demographic stochasticity (random nature of births and deaths)
Environmental stochasticity (variability)
Catastrophes (cyclones, epidemics)
Human impacts (habitat loss, fragmentation, pollution, hunting, pest spcies, climate change etc)
What is the biological species concept? WHat are the problems?
Defining a population as a group of organisms which reproduce with one another to form viable offspring
However, the problem is that there is often cross - species breeding (hybridisation): i.e. a lion and a tiger (liger)
What are some other species concepts
Phylogenetic species concept
Ecological species concept
Morphological species concept