2.4-2.5 (Kognity only) Flashcards
K Strategists
Produce very few offspring, increase the quality of them by investing in parental care. Quality means first for purpose. Survive long enough to reproduce
r strategists
Focus on the increased quantity of offspring at the expense of quantity. Little to no parental car. Survival is low but high numbers of offspring ensure survival
r strategists are beneficial in
Unstable, unpredictable environments. Early days of succession are unstable creating harsh environments thus they are more common in pioneer stages
K strategists are beneficial in
Stable environments. Succession stability increases with times so K strategists are more common in the climax community
Survivorship curve
Shows the number of individuals in a population of 1000 that are expected to survive a certain age. The Y axis is a logarithmic scale with 1000 individuals. X axis is the organisms relative age as a percentage of max lifespan
Type I survivorship curve
Indicative of the K-selected species. The curve starts out very flat showing a high survival rate in early life. This long life expectance causes the line to have a sharp drop at the end as the mortality increases dramatically.
Type II survivorship curve
the middle ground with a more or less constant mortality rate throughout the organisms life. That is they are as likely to die at birth as they are at old age.
Type III survivorship curve
typical of the r-selected species. The curve drops sharply immediately showing very low survival rates after birth. Very few individuals make it into later life.
Biome
Collection of ecosystems classified according to their predominant vegetation. They share similar climatic conditions and organisms that have adaptions to the environment
Biomes are one level down from
The biosphere, and cover large areas of the earth’s surface. Each having abiotic and limiting factors, productivity, biodiversity, and numerous ecosystems
5 categories of biomes
Aquatic Forest (tropical, temperate, boreal, taiga), Grassland (savanna and temperate), Desert (hot, coastal, cold), Tundra (Arctic, Alpine)
Aquatic biomes are:
Freshwater or marine
Marine biome
Deep ocean, coral reef, estuaries, mangrove swamps
Freshwater biome
Ponds, lakes, streams, rivers, wetlands such as bogs and swamps
Canopy layer
Dense layer made of taller deciduous of a tree or shrub - maple oak, birch, or gums depending on location. Not many animals live in the canopy because conditions are harsh. Exposed to winds and airborne predators
Ground layer
Mosses Lichens and liverworts
Herb layer
Grasses, ferns, lichens, and wildflowers, with snakes, mice, amphibians, and insects
Shrub layer
The canopy allows sunlight to penetrate so smaller trees, saplings, and low growing woody plants such as azaleas and blackberries are found here. Animals are frequent and protected by airborne attack by the canopy, high enough above ground to avoid forest floor predators. Animals found here are dependent on the location but include numerous birds, insects, and other small mammals
The drier climates (desert and tundra)
Have more extreme temperature ranges and both show maximum temperatures around June to September
Tropical rainforests show
No seasonal variations in temperature
Savanna has
Lower temperatures when deserts and tundra show the highest
Precipitation in biomes
Not all precipitation will be available to vegetation. In the tundra, precipitation is snow and falls and freezes until summer thaw. In hot deserts it might not make the ground, evaporating before reaching the surface. If it does make the ground, temperatures are high enough to cause evaporation of soil and surface water
Precipitation evaporation (P/E)
Addresses how much water stress there is within a biome
P/E above 1
Waterlogged or heavy leached soils
P/E below 1
Indicative of water shortages (deserts). Rainfall may soak into the soil but high evaporation rains will draw it back to the surface, causing salinisation
P/E of 1
Good soil moisture leading to fertile soil and good water available to plants
Net primary productivity in Biomes
High at the equator due to ideal growing conditions of high temperatures with plentiful sun/water. NPP drops towards the poles as growing conditions become less favourable. Deserts are close to the equator but have low NPP due to water scarcity despite good temperature and sunlight. Grasslands are lower due to seasonal rainfall and a dry season. NPP is low at the poles due to lack of water and sun
Succession
A change over time, changes in the plant community cause changes in the physical environment. May occur alone (on fresh lava the whole area will go through succession through time) - but on a sand dune it is seen with zonation
Sand dunes
The area closest to the sea is at the beginning of succession, as you move away from the sea the sand dunes succession has progressed until you move into grass and onto woodland. The physical conditions change so zonation appears
Zonation
A spatial change in response to changing conditions. Occurs without succession (rocky shore demonstrates it due to tidal changes and not succession). Plant communities adapt to the different environmental conditions. Change in vegetation community along an environmental gradient
Zonation changes may occur
By change in altitude, depth of water, tidal levels, distance from sure etc. They are spatial and determined by changes in abiotic factors. It is also triggered by changes in climatic conditions with increased altitude
Changes up a mountain may include (zonation)
Shortening of the growing season by lower temperatures and longer periods of freezing, more precipitation and a change of rain to snow with longer periods of snow coverage, higher rates of isolation, strong winds for longer periods of time
As distance from the shore increases
The vegetation communities change with changing conditions
Moving away from the sea (sand dunes)
Soil changes: depth and humus content increase, pH decreases moving from alkaline to neutral, moisture holding capacity improves, sea spray and winds decrease
Succession is the
Predictable change in a vegetation community over time. It starts with a pioneer community then transitions through intermediate communities to the final climax community. The ecological community changes composition. Some species starts this process as dominant species but die out replaced by an alternative dominant species. Through time vegetation becomes taller and the ecosystem more complex
Types of succession
Hydrosere, Halosere, Psammosere, lithosere, xerosere
Xerosere
Succession in dry areas
Halosere
Succession in salt water marches
Lithosere
Succession starting from bare rock. Seen on lava flows
Psammosere
Along sand dunes, stabilises them and stops them from shifting
Hydrosere
In a body of freshwater, small lakes may disappear and be replaced by plant communities
Factors can be measured
At a particular point in time, changing over space, changing through time
Sampling
“A process used in statistical analysis in which a predetermined number of observations will be taken from a larger population”
Three main sampling techniques in ESS
Random, systematic, stratified
Sampling in ESS
Establishes when and where to measure biotic and abiotic factors and/or how they change. Spatially they may change along an environmental gradient, temporal changes can be measured through succession, and abiotic and biotic factors can be measured as part of an EIA
Random sampling strategies
Pair of numbers as a point, random areas as a square with two numbers in the bottom left corner, random lines by generating two pairs of numbers and joining them
Advantages Random Sampling
Unbiased, suitable for large populations
Disadvantages Random sampling
You may not have access to some sample points, in larger areas the sample points may miss some places
Systematic sample
Choosing a number (n) eg: every 5 people, every 30 minutes, every metre
Advantages systematic
Easier than random with no need for a grid, coverage of the whole area achieved
Disadvantages systematic
May be biased as places have different chance of selection, patterns may be missed or areas exaggerated
Stratified sampling
When the population contains subjects eg: 30% under 21, 50% between 22-17. It should have the same proportions in each age group. It does not stand alone and is combined with one of the other two to select areas