biology unit 2 aos 2 - reproduction and ecosystems

Asexual reproduction

A mode of reproduction in which a single parent reproduces without the fusion of egg and sperm

Fission

The division of a parent cell into two or more cells is called fission, the two types are binary fission and multiple fission

Budding

Single celled organisms develop small buds or growth on the side of the parent cell which grows into genetically identical cells

Fragmentation

AR where body of multicellular organisms divides into many parts, genetically identical, heal themselves at site of wound, worms

Sexual reproduction

A mode of reproduction where a female gamete fuses with a male gamete to produce offspring

Somatic cell nuclear transfer

Involves taking the nucleus from a somatic cell, such as skin cell and transferring it into an enucleated cell

Ecosystem

A community of interacting organisms and the physical factors that surround them

Population

A group of the same species that occupy an area

Food web

A network of the energy flow of feeding relationships and interacting organisms in an ecosystem

Symbiosis

A close physical and long term relationship between two organisms of different species

Mutalism

A relationship between two organisms where both benefit eg. Bees and flowering plants

Commensalism

A relationship in which one organism benefits and the other is unaffected, rare in nature

Eg. Remoras and sharks

Parasitism

A relationship in which one organism (parasite) benefits by living in or on the body of another (host) which is affected

Eg. Mosquito and human

Competition

A relationship in which members of one or different species rival for overlapping or limited resources

Intraspecific

Organisms of the same species connecting for resources (intranet - compass/carwatha)

Interspecific

Organisms from different species competing for resources (internet - everyone)

Population size

The number of individual organisms of the same species, living in the same area at the same time

Population density

A measure of the average number of individual organisms living in a given area, all species have an optimum number so there is enough resources

Population distribution

The way in which members of a population are dispersed in a specific area, can be uniform, random or clumped,

Predation

When one organism kills and consumes another organism

Keystone species

a species that has a large effect on its environment and the ecosystem (the food web and energy flow)

Adaptions

Are an adjustment to an organisms environment to increase its chances of survival

Fire stick farming

Indigenous Australians use burning as a way of regenerating the local environment, reduces dry vegetation, leaf litter and other fuel for a bushfire, less fuel available means a later fire will have less material to burn and be less intense

Vegetative reproduction

Asexual reproduction where plant undergoes fragmentation to form another genetically identical plant, plant grows roots and leaves and eventually becomes a clone, strawberries produce special roots or runners that grow genetically identical offspring

Parthenogenesis

Occurs when the embryo has developed from an unfertilised egg, two egg cells fuse and produce an offspring with different mixes of mother’s genetic material

Advantages of AR

only need 1 parent, can reproduce quickly, mature quickly, dominate certain habitats

Disadvantages of AR

limited diversity - genetically identical, vulnerable to disease/predator one dies they all do, limited phenotype variability, can overpopulate

Gametes

Egg and sperm cells

Advantages of SR

adaptable to environmental changes, higher diversity- greater survival, ability to eliminate harmful mutations (50% chance of being passed on from germline cells)

Disadvantages of SR

2 organisms required for gametes to fuse, time consuming (find mate, mating, care for offspring), slow developmental (take longer to reach sexual maturity)

Reproductive cloning

Clone implanted into surrogate, Produces a whole genetically identical organism

Therapeutic cloning

Clone is grown in a petri dish, Produces genetically matched tissue for medical purposes

Pros of cloning

Produces a new organism or tissue to help people, can be used to test cancer treatments or new vaccines, help with endangered species, animals with desirable traits

Cons of cloning

Expensive and unviable life

Steps to somatic cell nuclear transfer

1) nucleus is removed from a healthy egg

2) a nucleus is removed and transplanted from another cell, such as a skin cell

3) the nucleus is placed into the enucleated egg

4) a small electric shock needed to stimulate egg cell

Behavioural adaptations

Relate to how an organism acts to increase its likelihood of survival eg. Penguins huddle together for warmth

Structural adaptations

Physical characteristics such as colour and shape of an organism to enhance survival eg. Whale blubber for insulation

Physiological adaptations

The favourable traits that relate to an organisms internal systems eg. Hibernate during winter, venom to stun prey

Hunting

Is targeted and specific, to ensure the balance of resources is maintained in an ecosystem, eg. Leaving behind eggs or young animals to ensure next generation, use specific traps

Responsible cultivation

Indigenous people us knowledge of land and seasons to live sustainably, eat a large variety of food to ensure not one thing is over eaten

Binary fission

AR where single parent cell divides into two genetically identical daughter cells