Presentation on theme: "An adaptation (or adaptive feature) is an inherited feature of an organism that enables it to survive and reproduce in its habitat. Adaptations are the."— Presentation transcript:
An adaptation (or adaptive feature) is an inherited feature of an organism that enables it to survive and reproduce in its habitat. Adaptations are the end result of the evolutionary changes that a species has gone through over time. Adaptations may be: behavioral physiological structural (morphological) Adaptations Osprey: a diurnal bird of prey Spotted owl: a nocturnal bird of prey
Organisms have adaptations to exploit, to varying extents, the resources in their habitat. Where resource competition is intense, adaptations enable effective niche specialization and partitioning of resources. In the African savanna, grazing and browsing animals exploit different food resources within the same area or even within the same type of vegetation. Exploiting a Habitat
The large thorns and dense, tangled growth form of the acacias of the African savanna are adaptations to counter the effects of browsing animals such as antelope. Plants and Browsers Acacia forest
Tiny dik diks can only browse the lowest acacia branches, less than 1 m above the ground. Their small pointed muzzles avoid the hooks and spines that defeat clumsier browsers. Impalas, with their larger muzzles and longer necks, can reach three times higher than dik diks. African Browsers 1 Dik dik cm at shoulder 3-7 kg Impala cm at shoulder kg
The disproportionately small head of the gerenuk allows it to browse between the thorny branches. Swiveling hip joints allow it to stand erect and reach taller branches. Giraffes browse the upper branches of the acacia. Its long (45 cm) muscular tongue is impervious to thorns and its long neck is so mobile that its head can tip vertically. African Browsers 2 Gerenuk cm at shoulder kg Giraffe 3.3 m at shoulder 6 m to crown tonne
Organisms have adaptations for: Biorhythms and activity patterns, e.g. nocturnal behavior Locomotion (or movement) Defense of resources Predator avoidance Reproduction Feeding These categories are not mutually exclusive. Purposes of Adaptations
‣ Structural adaptations: physical features of an organism, e.g. presence of wings for flight. ‣ Behavioral adaptations: the way an organism acts, e.g. mantid behavior when seeking, capturing, and manipulating prey. ‣ Functional (physiological) adaptations: those involving physiological processes, e.g. the female mantid produces a frothy liquid to surround and protect the groups of eggs she lays. Types of Adaptations Praying mantis
‣ Fitness is a measure of how well suited an organism is to survive in its habitat and its ability to maximize the numbers of offspring surviving to reproductive age. Adaptations are distinct from properties which, although they may be striking, cannot be described as adaptive unless they are shown to be functional in the organism’s natural habitat. Adaptations and Fitness The fur of this cat is a striking property... Mothering and play behaviors are adaptive
‣ The adaptations found in plants reflect both the plant’s environment and the type and extent of predation to which the plant is subjected. Many plant adaptations are concerned with maintaining water balance. Terrestrial plant species show a variety of structural and physiological adaptations for water conservation. Plants evolve defenses, such as camouflage, spines, thorns, or poisons, against efficient herbivores. Plant Adaptations
Water Balance in Plants Plants can be categorized according to their adaptations to particular environments: Hydrophytes: live partially or fully submerged in water. Halophytes: salt tolerant species found in coastal and salt marsh environments. Xerophytes: arid adapted species found in hot and cold deserts. Halophyte: spinifexXerophyte: cactusHydrophyte: water lily
Conserving Water Adaptation for water conservation Effect of adaptation Example Thick, waxy cuticle to stems and leaves Reduces water loss through the cuticle Pinus spp., ivy, sea holly, prickly pear Reduced number of stomata Reduces the number of pores for water loss Prickly pear, Nerium sp. Leaves curled, rolled or folded when flaccid Reduces surface area for transpiration Rolled leaf: marram grass, Erica spp. Pinus Prickly pear: Opuntia Marram grass
‣ Hydrophytes are plants that have adapted to living either partially or fully submerged in water. Typical features of submerged hydrophytes, e.g. the water lily (Nymphaea alba), include: Large, thin, floating leaves Elongated petioles (leaf stalks) Reduced root system Aerial flowers Little or no waxy cuticle Poorly developed xylem tissue Little or no lignin in vascular tissues Few sclereids or fibers. Adaptations of Hydrophytes
The aquatic environment presents different problems to those faced by terrestrial plants. Water loss is not a problem and, supported by the water, they require little in the way of structural tissues. Hydrophytic Plants Submerged leaves are well spaced, finely divided, and taper towards the surface Floating leaves have a high density of stomata on the upper surface Water lily Nymphaea alba Water milfoil Myriophyllum spicatum Cross section through the petiole Cortex Abundant, large air spaces Vascular bundles
Adaptations of Halophytes ‣ Mangroves are halophytes, adapted to grow in saline, intertidal environments, where they form some of the most complex and productive ecosystems on Earth. Mangrove adaptations include: Ability to secrete salt or accumulate it in older leaves. Specialized tissue that allows water, but not salt, to enter the roots. Tissue tolerance for high salt levels. Extensive root systems give support in soft substrates; oxygen enters the roots through pneumatophores. Mangroves, USA
Plants adapted to dry conditions are called xerophytes and they show structural and physiological adaptations for water conservation. Desert plants, e.g. cacti, cope with low rainfall and potentially high transpiration rates. They develop strategies to reduce water loss, store water, and tap into available water supplies. Dry Desert Plants Water table low Shallow, but extensive fibrous root system Stem becomes the major photosynthetic organ, and a reservoir for water storage. Surface area reduced by producing a squat, rounded shape. Leaves modified into spines or hairs to reduce water loss
‣ Tropical forest plants live in areas of often high rainfall. Therefore, they have to cope with high transpiration rates. Tropical Forest Plants Shallow fibrous root system Funnel shaped leaves channel rain Water table high Water loss by transpiration
‣ Ocean margin plants, e.g. intertidal seaweeds and mangroves, must cope with high salt content in the water. Ocean Margin Plants Some mangrove species take in brackish water and excrete the salt through glands in the leaves. Seaweeds growing in the intertidal zone tolerate exposure to the drying air every 12 h. Mangrove pneumatophores
‣ Insectivorous plants are plants that obtain extra nutrients by capturing and digesting small invertebrates. They are commonly found in marginal habitats such as acid bogs or nutrient-poor soils. They are often small because of the marginal habitats in which they live. They make their own sugars through photosynthesis, but obtain nitrogen and minerals from animal tissue. Leaf modifications act as traps. Usually the traps contain special glands that secrete digestive enzymes. Insectivorous Plants Sundew (Drosera) Pitcher plant
No animal exists independently of its environment, and different environments present animals with different problems. Animals exhibit a great diversity of adaptations. These enable them to live within the constraints of their particular environment. Animal Adaptations Extreme cold Forested Arid
Rodents and Lagamorphs Lagamorphs (rabbits and hares) and rodents are two successful and highly adaptable mammalian orders. Although different in many respects, they share similar adaptations, including early maturity, high reproductive rates, chisel-like teeth, and dietary flexibility. They are found throughout the world (except in Antarctica) in habitats ranging from Arctic tundra to desert and semi- desert. Capybara: the world’s largest rodent Jackrabbit: a lagamorph
Structural Adaptations in Rabbits Structural adaptations Widely spaced eyes gives a wide field of vision for surveillance of the habitat and detection of danger. Long, mobile ears enable acute detection of sounds from many angles for predator detection. Long, strong hind legs and large feet enable rapid movement and are well suited to digging. Cryptic coloration provides effective camouflage in grassland habitat. Rabbits are colonial mammals that live underground in warrens and feed on a wide range of vegetation. Many of their more obvious structural adaptations are associated with detecting and avoiding predators.
Functional Adaptations in Rabbits Functional (physiological) adaptations are associated with physiology. The functional adaptations of rabbits are associated with detecting and avoiding predation, and maintaining populations despite high losses. Functional adaptations High reproductive rate enables rapid population increases when food is available. Keen sense of smell allows detection of potential threats from predators and from rabbits from other warrens. Microbial digestion of vegetation in the hindgut enables more efficient digestion of cellulose. High metabolic rate and fast response times enables rapid response to dangers. Hawks are major predators of rabbits
Behavioral Adaptations in Rabbits The behavioral adaptations of rabbits reflect their functional position as herbivores and important prey items in many food webs. Behavioral adaptations Freeze behavior when startled reduces the possibility of detection by wandering predators. Thumps the ground with hind legs to warn others in the warren of impending danger. Lives in groups with a well organized social structure that facilitates cooperative defense. Burrowing activity provides extensive underground habitat as refuge from predators. Freezing is a typical behavior when threatened
Monitor Lizards 1 Goannas or monitor lizards are top predators, found in a wide range of habitats, from aquatic to arid semi-desert. They are strict carnivores and eat a range of animal species, including carrion. They are diurnal and active in all seasons. Body temperatures of up to 38°C are maintained through basking and other behaviors.
Strong neck and jaw muscles aid in holding, shaking, and subduing prey. Adaptations of monitor lizards (Varanus spp.) include: The gular (throat) pouch is inflated during threat displays. Rapid movements of the gular region when the mouth is open is used as a cooling mechanism. The upper jaw can move independently of the rest of the skull to facilitate swallowing of prey whole. Monitor Lizards 2 Skin color is related to the environment. The skin of species in arid regions is highly reflective.
The snow bunting (Plectrophenax nivalis) is a small ground feeding bird that lives and breeds in the Arctic region. Snow buntings are widespread throughout the Arctic and sub-Arctic islands. They are active 24 hours a day, resting for only 2-3 hours within that period. Snow buntings migrate up to 6000 km but are always found at high latitudes. They have the unique ability to molt very rapidly after breeding, changing color quickly from a brown summer plumage to the white winter plumage. Snow Bunting 1 Siberia Asia Europe Summer breeding area Winter migratory destination North America North Pole
Snow Bunting 2 Adaptations of the snow bunting (Plectrophenax nivalis) include: The internal spaces of the dark colored feathers are filled with pigmented cells. More heat is lost from the dark summer plumage. During snow storms or periods of high wind, snow buntings will burrow into snowdrifts for shelter. Snow buntings, on average, lay 1-2 eggs more eggs than equivalent species further south. In continuous daylight, and with an abundance of insects at high latitudes, they are able to rear more young. White feathers are hollow and filled with air, which acts as an insulator. Less heat is lost from the white winter plumage.
Trophic Structure 1 Every ecosystem has a trophic structure: a hierarchy of feeding relationships which determines the pathways for energy flow and nutrient cycling. Species are assigned to trophic levels on the basis of their nutrition. Producers (P) occupy the first trophic level and directly or indirectly support all other levels. Producers derive their energy from the sun in most cases. Hydrothermal vent communities are an exception; the producers are chemosynthetic bacteria that derive energy by oxidizing hydrogen sulfide. Deep sea hydrothermal vent
Trophic Structure 2 All organisms other than producers are consumers (C). Consumers are ranked according to the trophic level they occupy. First order (or primary) consumers (herbivores), rely directly on producers for their energy. A special class of consumers, the detritivores, derive their energy from the detritus representing all trophic levels. Photosynthetic productivity (the amount of food generated per unit time through photosynthesis) sets the limit for the energy budget of an ecosystem. Consumer (C3) Consumer (C2) Consumer (C1) Producer (P)
Organization of Trophic Levels Trophic structure can be described by trophic level or consumer level:
Major Trophic Levels Trophic LevelSource of EnergyExamples Producers Solar energy Green plants, photosynthetic protists and bacteria Herbivores Producers Grasshoppers, water fleas, antelope, termites Primary Carnivores Herbivores Wolves, spiders, some snakes, warblers Secondary Carnivores Primary carnivoresKiller whales, tuna, falcons Omnivores Several trophic levels Humans, rats, opossums, bears, racoons, crabs Detritivores and Decomposers Wastes and dead bodies of other organisms Fungi, many bacteria, earthworms, vultures
The sequence of organisms, each of which is a source of food for the next, is called a food chain. Food chains commonly have four links but seldom more than six. In food chains the arrows go from food to feeder. Organisms whose food is obtained through the same number of links belong to the same trophic level. Examples of food chains include: Food Chains 2° carnivore 1° carnivore Herbivore Producer (P) seaweed aquatic macrophyte cat’s eye freshwater crayfish whelk brown trout seagull kingfisher
Examples of Food Chains seagull starfish freshwater crayfish aquatic macrophyte brown trout kingfisher seaweedabalone
Food Chain Energy Flow Energy is lost as heat from each trophic level via respiration. Dead organisms at each level are decomposed. Some secondary consumers feed directly off decomposer organisms. Heat
Some consumers (particularly ‘top’ carnivores and omnivores) may feed at several different trophic levels, and many herbivores eat many plant species. For example, moose feed on grasses, birch, aspen, firs, and aquatic plants. The different food chains in an ecosystem therefore tend to form complex webs of feeding interactions called a food web. Food Webs
A Simple Lake Food Web This lake food web includes only a limited number of organisms, and only two producers. Even with these restrictions, the web is complex.
‣ Energy, unlike, matter, cannot be recycled. Ecosystems must receive a constant input of new energy from an outside source which, in most cases, is the sun. Energy in Ecosystems Organic molecule s and oxygen Carbon dioxide and water Cellular respiration Light energy Photosynthesis
‣ Energy is ultimately lost as heat to the atmosphere. Cellular respiration Heat Energy Cellular work and accumulated biomass ultimately dissipates as heat energy Static biomass locks up some chemical energy Growth and repair of tissues Muscle contraction and flagella movement Active transport processes, e.g. ion pumps Production of macromolecules, e.g. proteins Energy in Ecosystems
Living things are classified according to the way in which they obtain their energy: Producers (or autotrophs) Consumers (or heterotrophs) Energy Inputs and Outputs
Green plants, algae, and some bacteria use the sun’s energy to produce glucose in a process called photosynthesis. The chemical energy stored in glucose fuels metabolism. The photosynthesis that occurs in the oceans is vital to life on Earth, providing oxygen and absorbing carbon dioxide. Cellular respiration is the process by which organisms break down energy rich molecules (e.g. glucose) to release the energy in a useable form (ATP). Energy Transformations Cellular respiration in mitochondria Photosynthesis in chloroplasts
‣ Producers are able to manufacture their food from simple inorganic substances (e.g. CO 2 ). Producers include green plants, algae and other photosynthetic protists, and some bacteria. Producers Death Some tissue is not eaten by consumers and becomes food for decomposers. Wastes Metabolic waste products are released. Respiration Heat given off in the process of daily living. Reflected light Unused solar radiation is reflected off the surface of the organism. Dead tissue Growth and new offspring New offspring as well as new branches and leaves. Eaten by consumers Some tissue eaten by herbivores and omnivores. Solar radiation SUN Producers
‣ Consumers are organisms that feed on autotrophs or on other heterotrophs to obtain their energy. Includes: animals, heterotrophic protists, and some bacteria. Consumers Death Some tissue not eaten by consumers becomes food for detritivores and decomposers. Wastes Metabolic waste products are released (e.g. urine, feces, CO 2 ) Respiration Heat given off in the process of daily living. Dead tissue Growth and reproduction New offspring as well as growth and weight gain. Eaten by consumers Some tissue eaten by carnivores and omnivores. Food Consumers obtain their energy from a variety of sources: plant tissues (herbivores), animal tissues (carnivores), plant and animal tissues (omnivores), dead organic matter or detritus (detritivores and decomposers). Consumers
Producer tissue Nutrients released from dead tissues are absorbed by producers. Wastes Metabolic waste products are released. Respiration Heat given off in the process of daily living. Growth and reproduction New tissue created, mostly in the form of new offspring. ‣ Decomposers are consumers that obtain their nutrients from the breakdown of dead organic matter. They include fungi and soil bacteria. Decomposers Dead tissue Death Decomposers die; their tissue is broken down by other decomposers and detritivores Dead tissue of consumers Dead tissue of producers Dead tissue of decomposers Decomposers
The energy entering ecosystems is fixed by producers in photosynthesis. Gross primary production (GPP) is the total energy fixed by a plant through photosynthesis. Net primary production (NPP) is the GPP minus the energy required by the plant for respiration. It represents the amount of stored chemical energy that will be available to consumers in an ecosystem. Productivity is defined as the rate of production. Net primary productivity is the biomass produced per unit area per unit time, e.g. g m - 2 y -1 Primary Production Grassland: high productivity Grass biomass available to consumers
‣ The primary productivity of an ecosystem depends on a number of interrelated factors, such as light intensity, temperature, nutrient availability, water, and mineral supply. The most productive ecosystems are systems with high temperatures, plenty of water, and non-limiting supplies of soil nitrogen. Measuring Plant Productivity
The primary productivity of oceans is lower than that of terrestrial ecosystems because the water reflects (or absorbs) much of the light energy before it reaches and is utilized by the plant. Ecosystem Productivity kcal m -2 y -1 kJ m -2 y -1 Although the open ocean’s productivity is low, the ocean contributes a lot to the Earth’s total production because of its large size. Tropical rainforest also contributes a lot because of its high productivity.
‣ Secondary production is the amount of biomass at higher trophic levels (the consumer production). It represents the amount of chemical energy in consumers’ food that is converted to their own new biomass. Energy transfers between producers and herbivores, and between herbivores and higher level consumers is inefficient. Secondary Production Herbivores (1° consumers)... Eaten by 2° consumers