Ecology: Lecture 1 Flashcards
What is Ecology? What components does it observe?
Ecology is the science of how organisms interact with each other and with their environment.
- It includes both abiotic and biotic components.
Why is Ecology important and why is it relevant?
Animals and plants support all human life on earth, and we would be extinct without ecosystems.
- Ecology helps ensure that our ecosystems are sustainable.
What is the difference between abiotic and biotic?
Abiotic refers to non-living parts of an ecosystem, and includes climate, environment, nutrients that are cycled through ecosystems and required by organisms.
Biotic refers to living organisms in our ecosystems - plants, animals, fungi, bacteria, etc.
What supports our ecosystems?
Our ecosystem are what support fisheries, farms, food security. We derive economic benefits from these things, and ecosystems create the conditions for life.
What type of interactions do ecologists observe?
- competition within or across species: mutualism, food issues, etc.
- How populations are shaped by environmental factors (temp, clim)
Why is it important that ecosystems are sustainable?
We need to ensure that our ecosystems are sustainable as we want to continue to be supported and limit the loss of biodiversity.
Approaches of modern ecology?
- Observational studies
- Experiments
- Data Analysis and statistical modelling of patterns
- Remote sensing, drones, camera traps
Observational studies?
Creating a “natural history” and not manipulating/changing anything.
- observing species interactions with each other or within own population
Experiments?
Manipulate environmental factors to gauge how they will adapt. They might introduce new species, limit food, change climate, or change temperature, etc.
- This is done to understand the reason for the patterns we observe
Data analysis and statistical modelling of patterns?
Make daily maps of surface temp to see how it impacts the distribution of fish/whales, etc. Observe how it is linked to biodiversity.
- Census helps us model large-scale patterns to further understanding.
Remote sensing, drone, camera traps?
Observe data on a large scale then relate back to the observation. Use this data to map, take samples, take photos, etc.
- Determine what kind of animals in certain areas.
What do the later approaches distinguish ecology from?
The last three distinguish ecology from natural history. Ecology wants to answer the question of why and how these distributions occur.
Ecology: why plants and animals are found where they are, how that happens, the mechanisms that make this happen, how it evolved, and how it might change.
Fishing example with AIS?
AIS is required for large ships to have to keep track of them. Ecologists can use this map to observe global fishing outputs or “where things are going on”
- Tells us the distribution of fish, where it might be more intense or less.
Traditional ecological knowledge?
- Ecology is a modern science, but techniques and ideas have existed long before that
- Data can be collected by non-scientists, broadening the scope of their reach
- Indigenous knowledge has been increasingly integrated into ecological studies.
What do ecologists often study: distributions?
- Limits to distribution (why isn’t everything everywhere)
- Changing distributions and why
What do ecologists often study: abundance?
- Changes in abundance (can we predict extinction, why does it occur)
- Are populations growing or shrinking?
The importance of ecology in our world?
Climate change: affects food availability, animals, humans, ecosystems, life itself
Mass extinction: disease can become more prevalent, occurs when changes do.
Biodiversity loss: cannot maintain economic stability, natural habitats lost, biodiversity makes earth unique
Ecological issues: conservation and biodiversity?
Evaluate effectiveness of conservation strategies.
Do marine protected areas work?
- are populations increasing
- how much time spent in area
- is it working/effective
Ecological issues: Environmental issues?
Evaluate the consequences of human activities
What is the effect of climate change on biodiversity?
- effect on reefs
- effect on species living there
- effect on humans living there
Ecological issues: Wildlife & resource management?
Evaluate the effectiveness of management strategies.
When does fishing become overfishing?
- avoid economic collapse
- livelihoods
- economics/employment
Ecological issues: Pest Control?
Strategies for reducing crop losses
Why do some insects get out of control?
- how to change this
- use natural predators to fix this
- reduce crop from insect/pest
Ecological issues: human health?
How are diseases spread through animals (zoonotic disease)
What are the most important animal vectors for disease?
What is the role of climate?
And how will climate change affect pathogen spread?
How are changing distributions affecting disease risks in human beings.
Levels of study: Organism
How do organisms adapt to their environment?
- Interactions with same species
- Adaptations and their effects
Levels of study: Population
Within the same species
- Same area
Levels of study: Community?
Multiple species
- coral reef, desert
- mutualistic or parasitic relationships and their interactions
Levels of study: Ecosystem?
Organisms and the abiotic environment
- effect of the environment (energy, seasons, food)
Levels of study: Landscape or Seascape?
A range of connected ecosystems
- mountain range to forest to lake
- connected by species, runoff, etc.
Levels of study: Global ecology?
The biosphere
- largest possible
- everything together
Levels of study from smallest to largest ?
- Organism
- Population
- Community
- Ecosystem
- Landscape
- Global
Limits to distribution: why are there no trees in the far north?
Because of biomes!
- Habit
What are biomes?
Habitats covering large parts of the earth, terrestrial habitat defined by its dominant vegetation.
- a continuum, not sharp divides
Terrestrial biomes?
Major ecosystem type, classified by dominant vegetations
Tundra?
Treeless
- consists of small shrubs and vegetation
- tough and resilient vegetation
- This is because of the permafrost, which doesn’t allow complex or deep root systems to form
- It is difficult to compete as a tree here
Northern Coniferous Forest?
Consists of evergreen trees
- needles minimize water loss because they are small
- the precipitation levels matter
- there are strong seasonal signals meaning that they have to react faster and its too costly to drop the leaves
- nutrients are saved and not expended.
Temperate Broadleaf Forest?
Broad leaves (deciduous/drop)
- colour change, leaves gone, nutrient retained
- leaves are expensive so they drop, as light intensity is too low
- broad leaves are better for getting energy
- Take in more energy and make more energy
Tropical forest?
Evergreen broad leaves
- not dropped
- less harsh seasons
- some of the most diverse ecosystems
- very damp and very good for plants to thrive
- water and nutrients are abundant and there is intense sunlight year round
- very complex animal and plant life
Distribution correlated with latitude: hypothesis?
Hypothesis: climate drives the observed pattern
- temperature, precipitation, etc, structure these biomes and affect individual adaptations so no single species or vegetation type can dominate everywhere- all are adapted to different climatic conditions.
What drives transitions among frosted biome types?
Temperature and precipitation drive transitions among forested biome types
Savanna?
Grasses with a few trees:
- Grasses can tolerate drought and strong/short bursts of precipitation.
- Grows rapidly and manages better than trees.
- This is not the WHOLE story
Disturbance?
Disturbance is also important.
- It is an event that removes individuals from a populations
- Has an impact, things die and are removed.
2 types of disturbances in a savanna?
- Large herbivore grazers: stop trees from becoming established.
- Fire: grasses are faster to react and grow back easily.
What would happen to savanna ecosystems without disturbances?
Without fire and grazing animals, much of the savanna would be woodlands.
- Grazers and fire remove trees and grass
- Grass grows back more quickly
What drives the transition from forested to non-forested biomes?
Precipitation and disturbance drive transition from forested to non-forested biomes.
Temperate grasslands? `
Somewhat drier than the forest - strong seasonal signal.
- Not enough of a signal to maintain the system
- Disturbance events help
- If taken away, grasslands could easily become forests
- Less precipitation and has fires/grazers
Deserts?
Consists of shrubs mainly
- dry
Changing distributions case study?
Why has the range of the coyote increased over the past 100 years?
Coyote distribution?
The historical population of coyotes has doubled now.
What limits distributions?
- Dispersal
- Abiotic Factors
- Biotic Factors
Dispersal?
- The organism didn’t get there
- smaller animals aren’t always able to get far
- It is particularly difficult to get to or away from islands as they have many endemic species.
Abiotic factors limiting distributions?
- Temperature, moisture, salinity, oxygen (oceans)
- All animals are adapted to a particular set of conditions or environment.
Biotic factors?
- Resources, food, predation, competition, disease.
Coyote distribution: Wolf distribution changed?
Wolves are predators of coyotes, therefore there is more food pressure, extra competitors.
- enough overlap that the resources become strained
Wolf extermination?
Wolves hunt livestock, so humans killed them, reducing their distribution.
- Extermination of wolves made it easier for coyotes to expand eastward.
Coyote distribution: European Settlement?
Agriculture led to forest removal, allowing coyotes to compete more and have a larger range.
- Abundant rodents and other small prey (coyotes like)
- Habitat began to resemble grassland.
Forest to agriculture?
The conversion of forest to agriculture enabled coyote expansion.
What factors limited the coyote distribution?
- Resources, predation, and competition.
This was altered by humans.
What is a population?
A population is a group of individuals of a single species living in the same area.
Population interactions?
There can be positive, negative or neutral interactions in populations:
- Mate
- Compete for food
- Socialise
Population dynamics?
Composed of population size and density.
Population size?
Number of individuals
- 45 on Ram Mountain
Population density?
Number of individuals per unit area
- 1.25 sheep/km^2
What changes over time?
Abundance and density change over time, thus the population dynamics change.
Deserts occur when?
Typically 20-30 N/S of the equator
- Dry, temperature changes
- specialized ecosystem with low productivity and occasional pulses of rain.
Equator conditions?
Heat hits right on, with high intensity. Heat energy heats the air and cools when rising - holds less moisture and causes lots of precipitation
20-30 N/S conditions?
Energy is over a more dispersed area and dry patches align
Desert locusts?
Very specialized, form massive swarms, and devastating to vegetation.
Herbivores: eat own weight each day
Life cycle: 4 months, Egg - Juvenile - Adult
Desert locust populations?
Vary greatly, outbreaks and lows are reached cyclically.
- outbreaks are rapid increases in population abundance
- something allowed the population to grow and slow rapidly.
What is exponential growth?
- unlimited growth
- growth in an unlimited environment, resources are abundant.
- Bacteria, diseases
Exponential growth model?
dN/dt = rN
dN/dt: change in population
r: per capita growth rate
N: population size
Meaning of r sign?
Positive r: grows
Negative r: declines
0: no change in size
large vs. small r?
Large r: faster growth
Small r: slower growth
Per capita growth rate?
‘r’ is the per capital growth rate
What is r determined by?
r is determined by four per capital rates:
- Birth rate
- Death rate
- Immigration rate
- Emigration rate
r equation?
r = b-d + i-e
Closed population
A closed population has no immigration or emigration.
Equation is r = b-d
b > d = grows
b < d = declines
b = d = stays the same
For the same r?
For the same r, a large population will grow more than a small one.
Net per capita migration rate (m)
Difference between immigration and emigration rates: m = i - e
Positive: I > e
Negative: I < e
Zero: I = e
Open population - r depends on?
Per capita population growth (r) depends on per capita birth, death, and net migration (m) rates.
Therefore: r = (b - d + m)
Locust outbreaks are caused by what?
For some reason, birth rate became much higher than death rate.
b»_space; d - very rapid exponential
Birth and death rates depend on the environment.
Hypothesis of outbreaks?
Outbreaks are caused by environmental change
What events lead to a breakout?
- Heavy rainfall
- New vegetation
- Higher survival and births
- Clumping
- Crowding
- Gregarization
What happens with more food?
Females lay more eggs, and more hoppers survive.
birth goes up and death goes down, therefore r increases and rapid growth ensues.
What is gregarization?
Hoppers become fairly social, leg hairs come together and brush up together, causing appearances and behaviour changes.
Solitary hoppers?
Low density
Pale green
Fly alone at ngiht
Gregarious hoppers?
High density
Strong colours
Fly in swarms during day
How do they become gregarious?
Mechanical stimulation
Hormones (serotonin)
Behaviour changes in hours
Colour change at moult
Adult swarms bring that?
Increased mobility
Move across continent
Why do outbreaks end?
- Rains end, no new vegetation
- Locusts have eaten everything
- No longer crowded, revert to solitary form
Control efforts?
- Primarily pesticide spraying
- Predict and control where they go to prepare.
What do ecologists study?
- Limits to distribution of organisms
- Changes in distributions
- Changing abundance
Distributions?
- Limited by abiotic and biotic factors
- May change if limiting factors change
Abundance?
- Per capita growth rate is a function of births, deaths, immigration, and emigration
- Grow when r > 0
- Birth and death rates are influenced by the environment.
