chapter 9-10 Flashcards
Natural selection
Nature selects who would live and who wouldn’t ( different frog colour example
asexual reproduction advantages and Disadvantages.
asexual reproduction:
–>ADVANTAGES
-only one parent is needed, does not rely on another organism less energy required to find a mate
-very quick process
-allows a single organism to quickly colonise a new area
–>DISADVANTAGES
-lack of genetic variation reduces the chance of a population adapting to a new environmental condition
-pressure on availability of recourses
- if conditions change entire population can be lost
external fertilization features and where they occur
External fertilisation occurs when animals release their gametes into the external environment so that fertilisation occurs outside the body of females. Features of external fertilisation include the following:
Very large numbers of gametes are produced.
Large numbers of gametes increase the chance of fertilisation but also mean there is much gamete wastage.
aquatic environment
Internal fertilisation
Internal fertilisation occurs when males deliver sperm directly into the reproductive tract of females so that fertilisation of eggs occurs inside the body of females. Features of internal fertilisation include the following:
It has an energy cost of finding, attracting and securing a female mate.
It has the benefit of increasing the chances of the gametes meeting, and therefore increases the chances of fertilisation.
It occurs in some aquatic organisms as well as in terrestrial organisms.
All terrestrial animals use internal fertilisation, except for amphibians, such as frogs and toads that mate in the water.
Somatic cell nuclear transfer (SCNT)
The nucleus of a cell is removed, creating an enucleated cell.
The nucleus of another cell can be transferred to an enucleated cell to form a redesigned nucleated cell.
An enucleated cell can be fused with a somatic cell using a short electrical pulse
Biodiversity, its importance and the three levels: Genetic, Species &
ecosystem.
Biodiversity can be defined as the “variety of life in our natural world” and is measured as the number of different species—including plants, animals, fungi, algae, and even microorganisms, like bacteria—that share a certain home region. Biodiversity is a key indicator of the health of an ecosystem.
Genetic diversity refers to the variety of genes or the number of different inherited characteristics present in a species. Different populations of the same species may have different levels of genetic diversity. Populations with a high level of genetic diversity are more likely to have some individuals that can survive and reproduce when environmental conditions change. Genetic diversity is created through mutations, or changes, in an organism’s DNA that are passed on to the next generation.
Species diversity refers to the variety of different kinds of organism living in a particular habitat or region; for example, the diversity of plant species of the Gibson Desert.
Ecosystem diversity refers to the variety of physical environments in which organisms live and with which they interact. They range from biologically rich ecosystems, such as coral reefs and rainforests, to biologically sparse ecosystems
Genetic diversity importance
Genetic diversity:
increases species survival following environmental change
increases the number of individuals that can survive and reproduce
increases biodiversity in ecosystems
means natural selection can act, as there are many alleles to select from.
abiotic factors
abiotic factors nonliving factor, such as weather, that can affect population size
tolerance range
tolerance range extent of variation in an environmental factor within which a particular species can survive
Adaptations for survival (Behavioural, Physiological, structural)
Structural
Physical features of an organism that enable them to survive in a given environment
Blubber in seals providing a protective layer from the cold temperatures of the ocean
Physiological
Internal and/or cellular features of an organism that enable them to survive in a given environment
Vasoconstriction of blood vessels that conserves heat and increases blood pressure
Behavioural
Activities that an organism performs in response to internal and external stimuli
Huddling in penguins to stay warm, migration of birds to warmer regions over winter
limiting factor
limiting factor environmental condition that restricts the types of organism that can survive in a given habitat
Survival without drinking: the tarrkawarra
he tarrkawarra, or spinifex hopping mouse (Notomys alexis), is a placental mammal that lives in sandy deserts in Australia (figure 10.9). Because it can survive without drinking liquid water, the tarrkawarra can endure long periods of drought. Its kidney tubules reabsorb almost all the water from the kidney filtrate so that it produces highly concentrated and almost solid urine.
Survival by dormancy: frogs in the outback
The frogs then go into an inactive state known as dormancy, in which both breathing and heart rate are minimal and energy needs are greatly reduced. Their low energy requirements are met from their fat reserves.
They remain buried and are protected from desiccation until the next rains come; this may be a wait of one or two years.
They come out of their dormant state only when soaking rains fall and soil moisture rises. Once activated, the frogs return to the surface to feed and breed in temporary pools.
camel survival
a double row of long eyelashes and slit-shaped nostrils that can be closed — both features protecting the camel from windborne sand particles (figure 10.15)
bony structures in their nasal passages that enable the water vapour in their outgoing breath to be absorbed; it is then exhaled as dry air
oval-shaped red blood cells; this enables the cells to continue circulating even when the viscosity (thickness) of the blood increases due to the camel becoming dehydrated and losing body water
the ability to produce very dry faeces because of a long colon in their gut
the inbuilt fat store in the hump; this is also a physiological adaption. As the fat stores are metabolised for energy production when food is scarce, the reactions also produce metabolic water for the camel.
A biotic factor….
(living) — the populations of various species that live in a given region ex.aquatic plants, fish, amphibians, and algae
Intraspecific
Interspecific
Intraspecific Competition for resources between members of the same species
Wheat crops competing for soil and nutrients
Interspecific
Competition for resources between members of different species Leopards and lions competing for the same prey
Amensalism
Amensalism
One organism is inhibited or destroyed, the other is unaffected Elephants stepping on ants — the elephant is unaffected, however the ant dies
Predator–prey
One species kills and eats the other Polar bears (predator) eat seals (prey) in the Arctic
Herbivore-plant
An animal eats a plant
Koalas eating eucalypt leaves
Parasitism
An organism living on or within another organism to derive a benefit, whilst harming the host A flea living on a golden retriever — the flea obtains food, however the golden retriever loses nutrients
Mutualism
A beneficial relationship between two species
Hummingbird and bee balm flower — the hummingbird gets nectar, the balm flower spreads its pollen
Commensalism
One member gains a benefit from the relationship, the other is unaffected
The clown fish and the sea anemone — the clown fish obtains shelter and food scraps, and the sea anemone is unaffected
embryo splitting
- Fertilization
The process begins with in vitro fertilization (IVF), where an egg is fertilized by sperm outside the body. This fertilized egg is allowed to develop into an early-stage embryo, usually reaching the 2 to 8-cell stage. - Embryo Splitting
At the appropriate stage (usually 2 to 8 cells), the embryo is carefully divided. Each of the resulting cells, or blastomeres, is capable of developing into a complete embryo because all the cells in the early embryo are totipotent (can develop into any type of cell). - Culturing the Split Embryos
The individual cells from the split embryo are cultured separately in conditions that support their development. They are allowed to continue dividing and form new embryos, essentially creating identical twins or clones of the original embryo. - Embryo Transfer
Once the embryos have reached a certain stage of development (usually the blastocyst stage), they are transferred into the uterus of a surrogate mother for gestation. - Pregnancy and Development
If successful, the embryos implant in the uterine lining, leading to pregnancy. The surrogate mother will carry the cloned embryos to term.
PTC its advantages and disadvantages
Tissue culture cloning of plants has several advantages:
Slow-growing plants can be produced in large numbers.
Plants can be cultured all year round in controlled conditions of temperature and day length, rather than relying on seasonal growth.
Virus-free tissue can be used to produce a large number of plants that do not carry the virus. (Viruses are responsible for many plant diseases that can affect commercial crops.)
Cultured plants can be transported from country to country. The sterile conditions in which they are cultured ensures that the plants are pest-free, so that lengthy quarantine periods are avoided.
