B4.2 - adaptations (4e) Flashcards
what is a fundamental niche?
potential of a species based on adaptations and tolerance limits in the absence of competition
what is a realised niche?
actual extent of a species niche when in competition with other species
- includes impact of human activity on the habitat of that species
what are similarities and differences between realised and fundamental niches?
similarities:
- both describe the habitat, relationship and role occupied by a species
differences:
- fundamental niche is the potential role but a realised niche is the actual role
- fundamental niche depends on adaptation of species but realised niche is limited by competition and predators
- realised niche is smaller than fundamental niche
what is competitive exclusion?
no two species can occupy the same niche in the same location
why does evolution remove competitive exclusion?
if one of the two species adapted and evolved accordingly, the species no longer occupies the same niche
what are the outcomes of competitive exclusion?
- restriction of both species to a part of their fundamental niche, which is called a realised niche due to limited resources
- elimination of one of the competing species which would be driven from the habitat as one of the 2 species will always have an advantage over the other
- mechanisms of elimination could be through extinction , displacement or evolution of the disadvantaged species
what are the adaptations of plants for harvesting light?
- leaves are flat, broad and angled to the sun
- chloroplast is concentrated in the palisade layer towards the tops of leaves
what are examples of plants adaptations for harvesting light?
- lianas - grow from the forest floor and use the tree as a scaffold to grow into the canopy to absorb light
- epiphytes - grow on branches of trees to reach the canopy
- strangler epiphytes - grow stems downwards to reach the ground and grow roots
- herbs - growing from forest floor are adapted to yow in the shade
- shrubs - adapted to absorb red wavelength of light that pass through leaves above
- canopy trees - sturdy wooden trunks allow leaves to be positioned above their competition
what is the relationship between dentition and diet in members of the homidae family?
observations of living mammals led to theories relating dentition to herbivorous or carnivorous diets , which allowed the diet of extinct organisms to be deduced
what is the dentition and diet of orangutans (pongo) ?
omnivores, but mostly leaves and fruit
long , pointed canines but don’t eat meat
what is the dentition and diet of gorillas?
herbivores
large canines, but don’t eat meat
what is the dentition and diet of chimpanzees (pan) ?
omnivores ; eat animals, fruits, stems and leaves
small incisors and Iong pointed canines
what is the dentition and diet of humans (homo)?
mostly omnivores
canines are too small and blunt, premolars and molars are wide with rounded ridges , associated with shearing and crushing plant material
what is the diet of paranthropus robusts and homo floresiensis?
paranthropus robusts - has the dentition of a herbivore
homo floresiensis - small canines and flat, broad molars suggest a plant-based diet
why must we be cautious when inferring diet from dentition?
however, archeological evidence, including tools, suggests that they did hunt, and so were more likely to be omnivores
what are examples of adaptations of herbivores for feeding on plants?
- aphids have mouthparts (stylets) which a now it to pierce into the phloem to drink sucrose-rich cap
- leaf-eating insects use sharp pinching motions to cut into leaves and ingest them
- cows have specialised back teeth which are broad and flat for grinding plant material
- cows have ruminant digestive systems (regurgitation of grass) and a symbiotic relationship with bacteria and archaea to break down cellulose
- giraffes have tough tongues to resist thorns of acacia trees
what are examples of animal adaptations for detoxifying toxins produced by plants?
some animals have metabolic adaptations for detoxifying the toxins produced by the plant
- insects very on microbes in digestive system to breakdown toxins
- moose have proteins in saliva to neutralise plant toxins (tannins)
- liver neutralises toxins that travel through the blood
what are physical adaptations of plants for resisting herbivory?
- thorns and spikes to injure and deter herbivores
- cellulose cell walls cannot be digested by many organisms
- thick bark prevents penetration
what are chemical reactions of plants for resisting herbivory?
- leaves and stems have ting silica hain which break when rubbed and release chemical irritants
- ricin ( phytoxin) is toxic (castor bean seeds)
- alkaloids produced by lupin which cause damage to digestive reproductive, immune and central nervous system
What are chemical adaptations of predation for finding prey?
- snakes use neurotoxins to paralyse and ingest it’s prey
- spiders produce chemicals that mimic set pheromones of moths to lure them in
what are examples of physical adaptations of predators for finding prey?
- excellent senses; sight and smell
- echolocation and ability to detect changes in electromagnetic fields called by nervous system of prey
- can move quickly and precisely to catch prey
what are behavioural adaptations of predators for finding prey?
- decision making based on energy expenditure and gain
- pack predation involves teamwork and a leader
- ambush predation involves hiding and pouncing on prey
- persistence hunting
- pursuit predators outrun their prey
what are chemical adaptations of prey resisting predation?
frogs produce poison on skin to disrupt muscle function and cause death of predator
what are physical adaptations of prey resisting predation?
- camouflague to reduce the likelihood of detection
- aposemitism is the use of bright and unusual colours to indicate that a species is dangerous
- mimicry is the use of warming colours and patterns
- growth of a protective shell or exoskeleton
what are behavioural adaptations of prey resisting predation?
- running or hiding from predators
- forming groups
- warning calls to alert prey or deter predators
