Ecology 1 Flashcards
Habitat, characteristics that describe it
the abiotic factors of the environment in which an organism lives
geographical location, type of ecosystem, physical location within ecosystem, physical and chemical conditions
Species distribution, determinants (limitations) of distribution – salmon example (what factors have to be satisfied
where an organism lives in the world
abiotic factors (T, water availability, light intensity, pH, soil salinity, food supply) as well as predators, disease resistance, reproductive rate and physical barriers .
Salmon: fast-flowing fresh water (natural selection), maximum 3 m deep (light penetration), gravel substrate (for nest building), water pH 5.5-8 (not very sensitive (wide range of tolerance), important for the eggs)
Environment – describe the adaptation of an organism to sand dunes and an organism to mangrove swamps
the living (biotic) and non-living materials (abiotic factors) in the area where certain organisms live
1. Grass to sand dunes
a) Rhizome (underground stem) grows deep to reach water that fell down due to erosion and it acts as an anchor in the unstable, shifting ground
b) Thick waxy cuticle reduces transpiration (there is little water available)
c) High soil salinity is solved be sugars accumulating in root cells and by doing that increasing the water potential and thus water uptake (concentration gradient fixed)
d) Plant is protected against strong wind by rolled up leaves which create pockets of humid air on the lower leaf surface (for stomata to work properly)
- Adaptations of trees to mangrove swamps
a) Salt glands on leaves to excrete excess salt
b) Stilt roots stabilize the tree in the soft mud
c) Cable roots grow close to soil surface where there is most oxygen
d) Buoyant seeds dispersed by ocean currents
e) Pneumatophores (vertical root branches) that grow into air and absorb oxygen for roots to use in anaerobic soil
f) Root epidermis coated in cork reducing salt permeability
g) Root and leaf cells contain mineral ions and C compounds to increase osmotic potential (increasing water uptake)
How is the range of tolerance (for an abiotic factor) investigated
line and belt transect method (spans in regular intervals of different levels of the investigated variable)
Coral reefs – depth, pH, salinity, clarity, temperature
The ideal temperature and pH of 25°C and 7.8 are ideal for coral reef development.
Depth is a limiting factor for coral reefs because low light levels and lower temperatures do not support their growth/metabolism.
Biome, how are they distinguished and determined, organisms in the same biome, types of biome
group of ecosystems that share similar abiotic conditions and geographic altitude and latitude – terrestrial biomes are distinguished primarily by their predominant vegetation, and determined by temperature and precipitation – in the same biome, organisms tend to be similar (convergent evolution)
Tundra (lowest T, low precipitation), Desert (highest T, lowest precipitation), Savanna (high T, some precipitation), Tropical forest (highest T, most precipitation), Mediterranean and Grassland, Temperature deciduous forest and Northern coniferous forests
Adaptations of organisms to life in 1) hot desert 2) tropical rainforest (two for each)
- Adaptations to life in hot desert
a) Xerophytes (desert plants) – water conservation by vertical pleated stems, very thick waxy cuticle-covering stem, spines instead of leaves, wide-spreading deep roots and CAM physiology (stomata opened during night to reduce transpiration (LIDS))
a) Fennec fox – nocturnal, underground dens, long, thick pale fur (light reflection), hair that covers pads of feet (insulation), large ears for heat exchange (increased SA), panting (no sweat glands), longer loop of Henle to reabsorb more water (camel humps store fat that releases metabolic water when broken dow) - Adaptations to life in tropical rainforest
a) Yellow meranti – tall to avoid competition for light, trunk is hard dense wood to protect against wind stress and smooth to shed rainwater rapidly, trunk buttressed at base for support in shallow soil, evergreen leaves to carry photosynthesis all year, leaf enzymes work in temp. as high as 35°C, flowers and seeds produced rarely and in large quantities to deter animals that eat them
a) Spider monkey – long arms and legs and flexible shoulders for climbing and swinging, large hook-like thumbless hands, feet and a long tail to grasp branches, developed larynx for communication, only awake in the daytime (vision better so movement between branches safer), breeding in any season, as food is always available
Community
group of populations interacting with each other within a given area
Ecological niche, fundamental vs realized niche
the position of a species within an ecosystem – where in the ecosystem it lives (determined by zones of tolerance for abiotic factors) and its ecological role (place in the food chain) – basic concept in ecology: each species in an ecosystems fulfills its unique role; no two species can occupy the same niche
Fundamental niche is the potential role of a species in its ecosystem (absence of competition) and realized niche is the actual role (limited by competition/predation)
Which two main factors are the ecological role determined by, describe each subtype
- O2 utilization for metabolic processes
a) Obligate aerobe (O2 inevitable for CR)
b) Obligate anaerobe (O2 toxic)
c) Facultative anaerobe (anoxic conditions tolerated) - Nutrition
a) Autotrophs – E for creating C-compounds comes from sunlight or redox processes (photoautotrophs or chemoautotrophs)
b) Heterotrophs – C-compounds obtained by consuming other organisms
i. Holozoic nutrition – food ingested, digested, absorbed, assimilated and egested
ii. Saprotrophic nutrition – feeding on dead organic matter by secreting enzymes onto it, digesting it externally and then absorbing the end products
c) Mixotrophs – combination of two types of nutrition
i. Facultative – alternate between the two depending on environmental conditions
ii. Obligate – can live only if they use both (e.g. “stealing” chloroplasts from other organisms and using them until they degrade)
Subtypes – examples (O2 and nutrition)
Obligate aerobe: Mycobacterium tuberculosis, most animals and plants
Obligate anaerobe: Clostridium tetani, methanogenic Arcaea
Facultative anaerobe: Yeast, Salmonella, E. coli
Autotrophs: methanogenic Archeans are chemo
Saprotrophic nutrition: Fungi, some bacteria
Facultative mixotrophs: Euglena
Archaea modes of nutrition
Chemoheterotrophs – source of E for ATP production is oxidation of C-compounds obtained from other organisms
Photoheterotrophs – source of E for ATP production is absorption of light for energy but C-compounds are obtained from the environment
Chemoautotrophs – source of E for ATP production is oxidation of inorganic substances (CO2)
Dental differences between carnivores and herbivores
Carnivores (mainly proteins and lipids, proteins are easy to digest and are mostly swallowed) have short and pointed incisors for striping meat, large canines, pointed premolars and molars for crushing and grinding
Herbivores (carbohydrates with a lot of cellulose, difficult to digest, food is chewed long) have chisel-shaped incisors for tearing vegetation, absent canines, broad premolars and molars with ridges to grind food
Herbivore adaptations for feeding on plants:
- Beetle mouthparts (biting off, chewing leaves)
- Tubular mouthparts (reaching and licking nectar)
- Aphid mouthparts (piercing leaves and sucking phloem sap)
Plant adaptations for resisting herbivory:
- Stings in stinging nettle
- Spines of a rose
- Synthesis and storage of secondary metabolites that are toxic to herbivores (resulted in plant-herbivore specificity)
Adaptations of predators and prey to their lifestyle
Predators:
- Large pointed upper front teeth for piercing prey to suck blood (vampire bats)
- Venom containing toxins to paralyze and kill prey (black mambas)
- Waving of a modified luminescent fin ray to lure prey (anglerfish)
Prey:
- Shells to protect soft parts of the body (limpets)
- Toxins accumulate from ragwort plants eaten (cinnabar moth larvae)
- Swimming in tight groups (schooling) in fish (blue-striped snappers)
Adaptations of plants for harvesting light:
- Trees have a dominant leading shoot, allowing rapid growth in height up
- Lianas climb other trees, using them for support, so they need less xylem tissue
- Epiphytes grow on the trunks and branches of trees so they receive more light than on the forest floor (but there is minimal soil for their roots)
- Strangler epiphytes climb up trunks of trees, outgrow them and shade out their leaves (eventually the tree dies)
- Shade-tolerant shrubs and herbs absorb the small amounts of light that reach the forest floor
Principal of the competitive exclusion
two species that occupy a similar niche in the same location cannot exist because one of the two will always have an advantage over the other leading to extinction/displacement/evolution of the other one – an invasive species lacks predators while the endemic species is usually the one that cannot compete
Population – breeding vs non-breeding
interactions within a population
interacting groups of organisms of the same species living in an area
non-breeding include competition for food or cooperation to avoid predation
How is population size estimated? Assumptions regarding one of the methods
Using quadrats for sessile organisms or capture-mark-release-recapture method for mobile organisms
Quadrats – generate random coordinates, place the quadrat there, count the number of organisms within, estimate the population size using formula: Population size = mean N(organisms per quadrat) x A(site, (m2)) / A(quadrat (m2))
Capture method – capture as many individuals as possible, mark them, release them, repeat the steps after some time, calculate the population size using Lincoln index: Population size = N(initially caught) x N(recaptured) / N(recaptured with marks)
Assumptions:
1. sample size large enough to be significant
2. no emigration, immigration or death
3. marking of organisms does not affect their survival
4. no misidentification of species
5. marked organisms do not lose their marks
