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Ecological Niche
A species' unique role in an ecosystem, both biotic and abiotic
Species will survive, grow, and reproduce ONLY when all dimensions of the niche are satisfied in an ecosystem
Habit Determination
Determined by zones of tolerance for abiotic factors
Food is Obtained by...
Synthesis through using light, water, CO2
or
Consumption of other organisms
To compete effectively, organisms must specialize or develop adaptations
Three Domains
Archaea, Bacteria, Eukarya
Archaea
Unicellular and have no nucleus, can survive in extreme environment (high temp, low pH, high [salt])
Metabolically diverse regarding energy used for ATP production
-phototrophic, chemotrophic, or heterotrophic
*hard to culture in lab and less well researched*
Phototrophic
Absorption of light via pigments (not chlorophyll)
Chemotrophic
Oxidation of inorganic chemicals (Fe2+, Fe3+)
Heterotrophic
Oxidation of carbon compounds
Anoxic Environment
environment that lacks oxygen
-swamps
-water-logged soils/muds
-intestinal tracts (guts) of animals
-deep lakes/seas
Oxic Environment
environment that contains oxygen
Categories of Oxygen Requirements (3)
Obligate Aerobes, Obligate Anaerobes, Facultative Anaerobes
Obligate Aerobes
Need continuous supply of oxygen, reside in only oxic environment (all animals/plants)
Obligate Anaerobes
Inhibited or killed by O2, reside only in anoxic environment (methanogenic archaea)
Facultative Anaerobes
uses oxygen when available, can reside in oxic or anoxic environment (E. coli - gut bacterium, Saccharomyces - yeast)
Autotrophs
Make their own carbon compounds from simple substances (CO2)
Photosynthesis
Uses energy from sunlight to fix CO2
Carbon is used to produce carbohydrates, amino acids, and other carbon compounds
Only occurs in eukarya and bacteria, not archaea
Groups that Photosynthesize (3)
-Plants
-Eukaryotic Algae (seaweeds and unicellular algae like chlorella)
-Bacteria (cynobacteria and purple bacteria)
Heterotrophs
Obtain carbon compounds from consumption of other organisms
Digestion, in most, occurs internally after ingestion
*all animals are heterotrophs*
Holozoic Nutrition
Food is swallowed before fully digested
Non-Holozoic Nutrition
Food is digested externally, then ingested (inject digestion enzymes into prey then absorb afterwards)
Stages of Holozoic Nutrition (5)
Ingestion, digestion, absorption, assimilation, egestion
Ingestion
Place food into gut
Digestion
Break large food molecules into smaller ones
Absorption
Transport digested food from inside gut to bloodstream across plasma membrane
Assimilation
use digested food to make macromolecules and incorporate them as part of body's tissues
Egestion
Remove undigested material from end of gut
Family Hominidae
Includes genera like humans (Homo), gorillas (Gorilla), and chimpanzees (Pan)
Some are exclusive herbivores, while others are omnivores
Relationship btwn Diet and Dentition
Studied through examination of skulls, allows for diet of extinct of extinct species to be inferred via dentition
Herbivore Teeth
Tend to be large and flat to grind fibrous plant tissues
Omnivore Teeth
Include a mix of different types, for both meat and plants
-flat molars in back (crush and grind) and sharper canines/incisors than herbivores (tear meat)
Mixotrophic Nutrition
Not exclusively autotrophic or heterotrophic
Facultative Mixotrophs
Either entirely autotrophic or entirely heterotrophic, but can switch between the two
ex. Euglena gracilis photosynthesizes light, but also feeds on detritus/smaller organisms via endocytosis
Obligate Mixotrophs
Rely on both autotrophic and heterotrophic methods of nutrition, cannot survive on just one
ex. some protists lack chloroplasts, so consume algae to steal chloroplasts
-use "klepto-chloroplasts" until they become degraded and need to be replaced
-also consume food for carbon compounds they cannot make
Herbivore Adaptation
Herbivores feed exclusively on plants, have mouthparts evident of adaptation to diet
ex. most insects show great diversity but are homologous (from same ancestor)
Insect Herbivore Mouthpart Adaptations
Either jaw-like mouthparts (beetles) to bite/chew and ingest leaf parts
or
tubular mouthparts (aphids) to pierce leaves or stems, reach phloem and feed on sap
Plant Adaptations to Herbivores (3)
1. Sharp-pointed spines to cause injury
2. Stingers to cause pain
3. Produces toxins
Plant Toxins
secondary metabolites, means not a part of the basic metabolic pathway
stored in any part of plant, usually seeds which are attractive to herbivores bc high [] of protein, starch, or oil
In response to toxins, some herbivores have developed metabolic adaptations for detoxification
Physical Adaptations
Predators: vampire bats have pointed and razor sharp teeth to pierce prey and feed on blood
Prey: Buff-tip moths look like broken twigs to camouflage and avoid predation
Chemical Adaptations
Predators: black mambas produce venom w/ neurotoxins that inhibit acetylcholinesterase to paralyze prey
Prey: Caterpillars of cinnabar moth accumulate toxic alkaloids from ragwort, black and yellow stripes serves as warning coloration
Behavioral Adaptations
Predators: Grizzly bears use ambush strategies to catch migrating salmon, some wait at top of waterfalls while others stick their heads underwater
Prey: Blue-striped snappers swim in tight schools and use sudden changes in direction to confuse predators
Rate of Change in Adaptations
-Behavioral adaptations change relatively quickly (ex blue tits)
-Structural adaptations take longer bc they are based on genetic changes (beak size in finches)
-Chemical adaptations are the slowest bc require new enzymes or regulators processes
Saprotrophic Nutrition
Saprotrophs secrete digestive enzymes into dead organic matter and digest externally b4 absorption (fungi/bacteria)
also known as decomposers
-breaks down carbon compounds in dead organic matter
-releases elements like nitrogen that can be used by other organisms in ecosystem
Plant Adaptations For Light
In environment w/ abundant water and suitable temps. plants compete for light
Forest Ecosystems Diversity for Obtaining Light (5)
Emergent trees, lianas, epiphytes, strangler epiphytes, shade-tolerant shrubs & herbs
Emergent Trees
Dominant leading shoot that grows rapidly, reaches canopy, unshaded by other trees
Lianas
Climb through other trees, using them for support
-no need to produce as much xylem (wood)
Epiphytes
Grow on trunks and branches of trees, access to higher light intensity but also less soil for roots
Strangler Epiphytes
Climb trunks of trees, encircle and outgrow them
-eventually shades out host tree, killing them (and leaving only strangler epiphyte behind)
Shade-Tolerant Shrubs and Herbs
absorb light that reaches forest floor
Fundamental Niche
Potential:
-range of biotic/abiotic conditions that a species tolerate, in absence of competition, entire fundamental niche would be occupied
*adaptations do not allow survival outside range*
Realized Niche
Actual:
-actual extent within fundamental niche that species occupies
-bc competition exists in ecosystems, species are excluded from totality of their potential
*realized niche typically only affects food supply, indirectly affecting species*
Competitive Exclusion
If one species outcompetes the other in all parts of fundamental niche, the outcompeted species (loser) does not have access to a realized niche
-species must have different realized niches to survive in ecosystem
*occurs when fundamental niches of 2 species overlaps, one species usually outcompetes the other*