MODULE 3 Flashcards
What is an ecosystem?
A biological community of interacting organisms and their physical environment.
What is an ecosysteme made up of?
Made up of organisms (biotic) living in an area that interacts with each other and with the non living (abiotiv)
What is selection pressure?
A selection pressureis the effect of an environmental
factor that differentially influences the mortality or fertility of members of a population with different phenotypes.
What is an example of selection pressure?
Predation by cheetahs creates a strong selection pressure for wildebeest to be fast runners
What are the different kinds of selection pressures?
• Scarcity of food • Competition for shelter • Competition for mates • Disease • Temperature • Weather conditions Predation
What is a selecting agent?
The specific environmental factor that is
responsible for a selection pressure.
What is a selective advantage?
An increased relative ability to survive or reproduce
under a given selection pressure.
What are biotic selection pressures?
Biotic selection pressures are selection pressures created by a living (or biological) selecting
agent
What are abiotic selection pressures?
Abiotic selection pressures are those which are exerted by a non-living, or non-biological
selecting agent such as.
Name biotic selection pressures
- Predation
- Disease
- Competition for food
- Competition for mates
Name abiotic selection pressures
Extreme temperatures • Weather events • Too much/little exposure to light • Aridity • Harmful chemicals
How and why did the prickly pear population change over time?
Was introduced from South America in the 19th century and became invasive, rendering 40000 km of QLD farmland unproductive.
In 1925, the C.Cactorum moth was introduced to eat the prickly pear, and in a short period, the population declined. Some areas are now resistant to moth larvae.
What is biological control?
A species introduced to a region to control the population of another species, usually a pest.
How and why did the cane toad population change over time?
Since the introduction of cane toads in 1835 they have continued to spread across Australia.
Compared to the toads in established QLD areas the toads at the invasion front have evolved to have longer legs, faster movement and metabolism for movement.
What selective advantage did the toads have?
For the long-legged fast-moving phenotype they face less competition for food in unoccupied areas.
What is an adaptation?
A feature of a species that has been altered by evolution to make the species better suited to its environment.
What is a structural adaptation? Give an example
The adaptation in the physical structure and build of living things. These physical features can be internal or external. For example, the blubber in a blue whale protects them from cold water.
What is a physiological adaptation? Give an example
Involves the body system or organs. Koalas survive on gum leaves even though they contain little nutrition as they have a low metabolic rate.
What is a behavioural adaptation? Give an example
The way an organism acts. Eg. Bats huddle on the roof of a cave, helping them share body heat.
How can social behaviour as an adaptation can increase a species chance of survival?
Often is exhibited for the survival of the group, warding away predators, staying hidden from predators, helping them survive during extreme temperatures or conditions in their habitat, as well as helping them obtain food and reproduce.
What is evolution?
Evolution is the change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes that are passed on from parent to offspring during reproduction.
What is genotypic variation?
The genetic differences between individuals that can be passed from parents to offspring.
What is a phenotype and what is phenotypic variation?
Phenotypes are traits or characteristics of an organism that we can observe, such as size, color, shape, capabilities, behaviors, etc.
Phenotypic variation, then, is the variability in phenotypes that exists in a population.
Why is there on average, less genotypic variation amongst wild populations?
The species are living under vaery strong selection pressures, meaning those that don’t suit the environment don’t survive. Unlike in domesticated populations.
What was Darwin’s observation regarding offspring?
Organisms produce more offspring than required to replace themselves
What do selective agents create?
A struggle for survival.
What was Darwin’s observation regarding regional variation?
CD observed that closely related species in locations that are isolated from each other by a geographical barrier exhibit significant variation in structure.
How does this observation relate to the Galapagos finches?
Closely related finches are found on each of the islands, but the size and shape of their beaks varies significantly.
Darwin was able to demonstrate that the beak morphology of the finches was able to be related to the types of available food on the various islands.
What is adaptive radiation?
The rapid divergent evolution of one species into several
new species, as a result of separate,
isolated populations of the species experiencing
different selection pressures.
What is genetic diversity?
The total number of genetic characteristics in the genetic makeup of a species.
What is species diversity?
The measure of the diversity of different species in an ecological community
What is the mechanism of evolution?
Natural selection is the mechanism of evolution. It is the differential survival and reproduction of individuals in a species, due to selective advantages and disadvantages conferred by heritable differences in their phenotype.
What was Lamarck’s theory about evolution?
Lamark believed that species evolved through acquired characteristics that are developed throughout an organisms life. He believed these traits were gained and passed on.
What is sexual selection?
A form of natural selection in which the selection pressure is the mating preference of the opposite
sex.
For some species, natural selection favours individuals who reproduce at the expense of survival.
What is the difference between geological history and evolutionary history?
Geological- The history of the earth since its formation.
Evolutionary-The history of life on earth since it first appeared.
What is directional selection?
An extreme phenotype is favoured over other phenotypes, causing the allele frequency to shift over time in the direction of that phenotype
How does directional selection relate to the evolution of the horse?
Early horses were smaller and had 4 toes. As time continued they got longer and the middle toe remained becoming the hoof. The advantage is less friction with the ground and more efficiency of movement.
What is allopatric speciation?
One species may diverge to give rise to two new species when: 1. A parent population is divided by a geographic barrier 2. There is no gene flow between the two daughter populations 3. Mutations (may) arise in each population (randomly). 4. Different selection pressures operate in each population.
What is the result of allopatric speciation?
The two daughter populations may evolve to become so different that even if the geographic barrier is subsequently removed, the individuals within those daughter populations no longer mate and produce fertile offspring
The horse is an example of what kind of evolutionary change?
Micro-evolution
What is microevolution?
Small scale changes within a population, takes place over shorter periods of time, doesn’t always create new species, can create varieties, breeds or races
What is macroevolution?
Takes place over millions of years, measured in geologic time and results in new species and groups such as families and orders rising.
How do microevolutionary changes cause speciation?
Small changes within a population lead to specialisation, as these changes progressively accumulate over a long period, causing the dramatic difference between the modern species and its ancestor.
What are the differences between the kaibab squirrels in the Grand Canyon?
In the Grand Canyon, the Kaibab squirrel are separated and geographically isolated by the Colorado river. One area is sunny, with the squirrels there having lighter fur and bushier tails. The darker side has darker squirrels and don’t have any white fur.
How is the Kaibab squirrel an example of allopatric speciation?
The squirrels on either side of the river, face different selection pressures, evolving to better suit their environment better. If the river was to dry up, they wouldn’t be genetically compatible anymore to mate and produce living fertile offspring.
How is the platypus an example of macroevolution?
It took place over an incredibly long period of time, resulting in a new species. This species is much more specialised than their early ancestors, having mammalian, amphibian and reptile qualities.
What is divergent evolution?
The pattern of evolution in which an ancestral species gives rise to two or more distinct species.
-In closely related species similarities between organisms results from their relatively recent divergence from a common ancestor.
How does natural selection support divergent evolution?
-Different selection pressures, different environments causing the species to evolve differently, but still have the same ancestor.
What is convergent evolution?
A pattern of evolution in which under similar selection
pressures, two unrelated species evolve similar
adaptations independently.
What is an example of convergent evolution?
Penguins and puffins- aren’t related but look similar due to their similar environments and selection pressures.
What are the two types of evolution that can exist in a species?
Punctuated equilibrium and gradualism
What is punctuated equilibrium
After a period of rapid evolution
following a speciation event, a species becomes
stable for a long period of time
Fossil record gaps-occurred too quickly for fossil formation
What is gradualism?
Populations slowly diverge by accumulating changes in characteristics due to different selection pressures. It suggests that transitional forms should exist
How does general biochemical evidence prove evolution?
All living things share the same macromolecules and DNA. Species that are most closely related have similar proteins and DNA.
What is the process of DNA hybridisation?
Splits double-stranded DNA lengthwise to expose the nucleotide bases on the individual strands. The separate sections are mixed to form a hybrid. The more closely the base pairs are, the stronger the binding of the strands.
What is an example of DNA Hybridisation?
The DNA of a human and a mushroom would be weakly combined compared to the DNA of a human and a chimpanzee.
Orangutan and human DNA is 97% the same. At what temperature would an orangutan-human DNA hybrid “melt”?
(At 87 degrees the two strands separate)
84 degrees
100-97=3
84+3=87
What are homologous structures?
Structures that have the same ‘plan’ but serve a different purpose.
Similarities in the structure of organisms imply that they have separated from a common ancestor more recently.
What is an example of homologous structures?
Mammals, birds and reptiles and amphibians have the same arrangement of bones in their forelimbs, yet they perform different functions.
What are analogous structures?
Serve the same purpose in different species but their underlying anatomical plan is fundamentally different
Example of convergent evolution
What is an example of analogous structures?
The wings of a grasshopper and the wings of a bird- same function different anatomical structures
What are vestigal structures?
An anatomical feature that no longer has a purpose in the current form of a species but did in its ancestor
What is comparative embryology?
Organisms that look similar as embryos share a common ancestor, pharyngeal folds are found on both humans and fish embryos, suggesting a common evolutionary origin.
What is biogeography?
The geographical distribution of organisms both living and extinct- ratites (emus and cassowaries in Australia, ostriches in Africa, Rheas in South America, elephant bird in Madagascar, kiwi bird in NZ)
What is the law of superstition?
Rock layers at the top are new, bottom are old
How does the law of superstition prove evolution?
Fossils in lower layers are simple, and new layers are complex, some species have disappeared, suggests species have appeared that weren’t there before.
What is radiocarbon dating and how does it date fossils?
n
How are cane toads modern examples of evidence for evolution?
The invasion front group have genes that enable them to move faster and this is a favoured characteristic. This group moves more and areas inhabited by them are showing changes in structural and behavioural characteristics.
How are cane toads modern examples of evidence for evolution? (crocodiles and snakes)
Redbelly black snakes have smaller heads now so they can’t eat the poisonous, larger toads
QLD crocodiles have become toxin resistant but NT haven’t (toxin= selecting agent)
How is anti-biotic resistance proof of evolution?
- High number of bacteria- some are resistant
- Antibiotics will kill the bacteria and the body’s good bacteria
- The resistant bacteria now have preferred conditions to grow and take over
- Bacteria transfers their anti drug resistance to other bacteria
What are the selective advantages in anti-biotic resistance?
Bacterial mutations, antibiotics have created a selective advantage for antibiotic resistant bacteria to thrive
