9 - Diversity and Adaptation (copy)

Habitat

The physical place or environment in which an organism lives.

Adaptation

A particular structural, behavioural or physiological characteristic of an organism that makes it better suited to its environment.

Ecosystem

A system of organisms interacting with one another and their non-living surroundings, including the community and habitat.

Community

The naturally occurring group of organisms living together as an ecological entity; the biological part of the ecosystem.

Abiotic vs biotic factors

Abiotic - Non-living components of an ecosystem e.g. pH, salinity, temperature, turbidity, wind speed

Biotic - Living components of an ecosystem e.g. competitors, parasites, pathogens, symbionts, and predators.

Genetic diversity

The range of genotypes of individuals in a population of a species or a species, essential for species survival in changing conditions.

Genetic diversity in asexual reproduction

Low diversity, only can be caused by spontaneous mutation.

Spontaneous mutation

Only way that completely new alleles can occur. Can be passed onto offspring in sexual reproduction of occurring in germline cells. Can result in beneficial traits improving survival.

Adaptations

Inherited characteristics that make organisms better suited for an environment. Does not include traits acquired throughout lifetime (these cannot be passed to offspring)

3 types of adaptations

Structural, physiological and behavioural

Structural adaptations

Anatomical or physical features of an organism that increase its survival chance.

Xerophytes

A group of plants adapted to live in dry conditions (includes some Australian plants, succulents and cacti), that have structural adaptations like fleshy stems, leaves and roots that swell up to retain water, maximise water reabsorption and minimise water loss. Important water source for Aboriginal people.

Types of structural leaf adaptations

-Thick, waxy cuticle layers in eucalyptus trees to reduce water loss through evaporation.

-Tiny cylindrical leaf shapes in cypress pines mean less surface area for water loss.

-Porcupine grass can roll up their leaves in hotter months to reduce the number of stomata exposed to hot temperature.

Structural adaptations in animals

- Thorny devil spikes deter predators and siphon water to mouth, also camouflaged colours

- Wombat joeys stay in pouch with a rear opening. Teeth specialised for tough fibres

Physiological adaptations

Features of an organism's functioning that increase its survival chance

Physiological adaptations in plants

- Frost resistance in Australian plants in cold environments

- Deciduous trees

- Salt tolerance or salt avoidance

Anti-freeze proteins

Bind to and inhibit the growth of ice crystals that are formed in the space in cell walls

Deciduous trees

As daylight decreases (or if drought occurs), a waterproof layer forms at the base of each leaf, preventing water from entering the leaf and halts photosynthesis, causing chlorophyll degeneration, exposing the pigment anthocyanin before the leaf dies.

Halophytes

Salt-tolerant plants like succulents that avoid toxicity due to high salt concentration by increasing cellular water content in large vacuoles, meaning sodium and chloride ions can accumulate in a cell.

Mangroves

A type of salt-avoidant plant that maintains minimal levels of salt in its cells by excluding up to 97% of salts at the roots and can actively secrete excess salts from glands and leaves can die off with excess salt.

Physiological adaptations in animals

- Osmoregulation through reabsorption and regulation of water excretion

- Thermoregulation through counter-current heat exchange, blubber and aestivation

Water reabsorption

Desert animals have high water reabsorption through the kidneys and reuse water produced by cell respiration e.g. spinifex hopping mouse

Osmoregulation in salt vs freshwater fish

Saltwater: Produce concentrated urine, have a low filtration rate and actively secrete ions

Freshwater: Produce dilute urine, have a high filtration rate and actively uptake ions

Counter-current heat exchange

Animals in colder regions transfer heat from blood traveling through the arteries to the foot to the colder blood returning to the body in the nearby vein.

Aestivation

Animals in a hot climate go into dormancy to reduce their metabolic rate and therefore internal body temperature, retaining water and conserving energy.

Behavioural adaptations

Ways an organism acts that increase its chance of survival

Behavioural adaptations in plants

Often occur due to physiological changes like rapid changes in turgor due to touch like touch-me-nots and venus flytraps

Behavioural adaptation in animals

- Thermoregulation by ectotherms and endotherms

- Group behaviour

Ectotherms

Animals that have fluctuating body temperatures in response to external temperatures so they rely on external sources of heat to regulate internal body temperature, e.g. snakes

Endotherms

Animals like mammals that maintain a constant internal body temperature by generating heat internally from cell metabolic processes, e.g. kangaroos rest in day and gather at dusk to feed, wallabies lick wrists w/ dense capillaries to cool

Group behaviour

Behavioural adaptations to ensure survival of a group, e.g. meerkat sentries

3 ways that species interact

Predation, competition and symbiosis

4 types of symbiosis

Parasitism, mutualism, commensalism and amensalism

What are the 3 effects that interaction between species and/or abiotic factors can have?

Benign, beneficial or harmful

2 types of competition

intraspecific competition - Competition within species for resources like water or mates increases as the population grows, becoming a limiting factor for the population

Interspecific competition - Competition between members of different species e.g. predator-prey relationships

Competition

Individuals compete for resources such as food, space, and mates. In all cases of competition, both parties (the competitors) are harmed to varying extents by the interaction.

Generalist predators

Maintain stable populations by prey switching (predating on different species as one species becomes scarce) in response to changing prey densities.

Predator-prey cycles

Fluctuations in the size of the population of prey species may be closely followed by fluctuations in the number of predators, particularly in predator species that have a definite preferred prey

Parasitism

A relationship between two organisms of different species where one (the host) benefits and the other (the parasite) is harmed but not usually killed. Both parasite and host show adaptations to the relationship.

Two types of parasites

Endoparasites and ectoparasites

Ectoparasites

Live externally on a host, sucking body fluids, causing irritation and possibly acting as vectors for pathogens. Includes lice, ticks and bed bugs

Endoparasites

Live within a host. May need two hosts to complete the life cycle:

- primary host (in which the parasite becomes sexually mature)

- one or more intermediate hosts (which usually house larval stages)

Endoparasitic adaptations

Specialized mouthparts, being long and thin, and lack of a digestive tract, enable them to spend their life inside the intestines of their vertebrate hosts.

Plant parasites

Hemiparasities - photosynthesizing but lack their own roots and rob their host plant of water and nutrients

Holoparasites - Entirely dependant on the host plant

Mutualism

A relationship that exists between organisms of different species that benefits both and harms neither. Two types are obligate and facultative mutualism

Facultative mutualism

When the mutualistic association of two organisms is beneficial but not obligatory for one or both species

Obligate mutualism

When the two species cannot survive without each other

Pollinators are an example of a __________ relationship?

Mutualistic; between plants and animals as pollen is spread and organism gets food

Commensalism

A relationship where one party (the commensal) benefits, while the host is unaffected.

Amensalism

A relationship where one of the species is inhibited or harmed, while the other is not.

What is the source of energy for most of Earth's ecosystems?

Light energy coming from the sun trapped by producers

Producers (autotrophs)

Organisms like green plants, algae, other photosynthetic protists, and some bacteria capable of manufacturing their food from simple inorganic substances (e.g. CO2)

What ecosystem doesn't rely on the sun for energy?

Hydrothermal vent communities where producers are chemosynthetic bacteria that derive energy by oxidizing hydrogen sulphide

Consumers (heterotrophs)

All organisms other than producers that obtain their energy in the form of chemical energy present in their food (autotrophs or other heterotrophs)

Decomposers

Consumers that obtain their nutrients from the external breakdown of dead organic matter. Includes fungi and soil bacteria

Detritivores

Derive their energy from the consumption of detritus (dead plant and animal materials) representing all trophic levels.

Trophic Levels

Organisms whose food is obtained through the same number of links belong to the same trophic level.

Food chain

The sequence of organisms, each of which is a source of food for the next, usually with around 4-6 links with arrows going from food to feeder.

Food web

The different food chains in an ecosystem tend to form complex webs of feeding interactions

Keystone species

A species that has a disproportionately large effect on other organisms within an ecosystem. The removal or decrease in numbers can cause a total collapse or allow for invasive species.

2 types of keystone species

Predators - control the population size and distribution of their prey to maintain ecosystem balance e.g. sharks w/ turtles

Ecosystem engineers - produce or change an environment, allowing for other species to survive and flourish e.g. beavers and mangroves

Sustainable harvesting

ATSI practices that meet their needs and conserve species, in order to avoid overhunting and protect ecosystem balance

How do ATSI people measure seasons?

They used changes in the landscape

Billabong

A pool of water left behind when a river alters its course or after floodwaters recede, that act as a valuable source of fresh water and an important ecosystem for many species.