biology assessment 1

Selection pressures

External agents influencing an organism's survival in an environment, can be negative or positive, may change over time, and can be density-dependent or density-independent.

what are density-dependent factors

Factors affected by population size in an ecosystem.

Density dependent factors

Predators

Availability of resources (e.g. shelter, water)

Nutrient supply

Disease/pathogen spread

Accumulation of wastes

what are density-independent factors

Factors unaffected by population size in an ecosystem.

density independent factors

Phenomena (e.g. natural disasters)

Abiotic factors (e.g. temperature, CO2 levels)

Weather conditions (e.g. floods, storms)

types of selection pressures

resource availability, environmental conditions, biological factors

resource availability (type of selection pressure)

presence of sufficient food, habitat (shelter/territory) and mates

environmental conditions (type of selection pressure)

temperature, weather conditions or geographical access

biological factors (type of selection pressure)

predators and pathogens (disease)

types of landforms

Desert or Arid zone

Shrubland

Open Woodland

Sclerophyll forest

Temperate rainforest

Tropical rainforest

Biodiversity

Variety of living things and interactions in an area.

genetic diversity

the variety of genes within a species, a species has different population, and genetic compositions. Not all groups of animals have the same degree of genetic diversity. If we want to maintain genetic diversity, we have to conserve the different species.

species diversity

the variety of species within a habitat or a region. Different regions have different levels of species diversity. species are grouped into families based on their shared characteristics.

ecosystem diversity

the variety of ecosystems in a given place. Ecosystem sizes vary etc GBR is very big.

types of biodiversity

genetic, species, ecosystem

factors of population growth/reduction

reproduction, migration, death rates, limited resources, limited habitat space, sex ratio for mating, selection pressures

Adaptations

Features developed through natural selection for its current function

Any alterations in the structure or function of an organism or any of its parts that result from natural selection and by which the organism becomes better fitted to survive and multiply in its environment. 

not all _______ are adaptations

traits

questions to assess adaptability

is it heritable

is it functional

does it increase fitness

types of adaptation

behavioural, structural, physiological

behavioural adaptation definition

things an animal does

behavioural adaptation examples

Migration, hibernation, mating dance, moving with the herd

structural adaptation definition

parts of the animal

structural adaptation examples

Shape of a bird’s beak, colouration, having wings

physiological adaptations definition

processes within the animal

physiological adaptations examples

Cellular respiration, life cycles, ability to produce venom

what were some facts about galapagos finches

showed distinctive features (beak structure), only a few migrated to the island and then distributed, common ancestor for each of the different finches

what caused the differences between species in the galapogas finches

inheritance, competition, variation and natural selection

Large-billed finches feed more efficiently on large, hard seeds, whereas

smaller-billed finches feed more efficiently on small, soft seeds.

how to write a case study

1. Name the organism

2. Name the characteristic

3. Describe the characteristic

4. Describe the environment

5. Explain how this characteristic gives a benefit to the organism’ survival in the environment it inhabits.

Ecosystem

An ecosystem includes all of the living things (plants, animals and organisms) in a given area, interacting with each other, and also with their non-living environments (weather, sun, soil, climate, atmosphere). 

Abiotic factors

Non-living physical and chemical elements in an ecosystem like water, air, and sunlight.

Biotic factors

Living or once living organisms in an ecosystem capable of reproduction, e.g. animals, plants, fungi

effect of biotic factors (list the factors)

availability of food, mates, predators, competitors

effect of biotic factors (availability of food)

low food availability = decrease in population and abundance

effect of biotic factors (mates)

Ability to find mates = reproduction and increase in population and abundance

effect of biotic factors (predators)

High amount of predators = decrease in prey population 

effect of biotic factors (competitors)

high amount of competition = competition for resource and decrease in population

effect of abiotic factors (list factors)

temperature, oxygen availability, water availability

effect of abiotic factors (oxygen availability)

low oxygen = low respiration and decrease in organisms that can inhabit an environment

effect of abiotic factors (water availability)

low water = competition for water and decrease in abundance species

if factors are positive they _______

if factors are negative they ______

 INCREASE abundance and diversity

DECREASE abundance and diversity 

why was the cane toad introduced

biological control for cane beetle.

why did cane toad population increase?

positive selection pressure. As a result the population of cane toads increase. 

name the positive selection pressures related to cane toads

Larger size and longer legs, Toads became fast-moving and directional due to spatial sorting, Increased food source of native fauna, Had no natural predators

name the negative selection pressures related to cane toads

Development of arthritis in older toads

overall statement on cane toads

 the population increases due to the positive selection pressures. Population now uncontrolled, invasive species

Competition

Rivalry among living things for resources, mates, shelter, and space.

interspecific competition

occurs among organisms of different species

intraspecific competition

occurs among the members of the same species. 

biotic impacts

the impacts of biotic factors in the ecosystem

predation, competition, symbiotic relationships

Symbiotic relationships

Long-term, close interactions between two or more biological species

types of symbiotic relationships

Predation, Parasitism, Commensalism, Mutualism

predation

A symbiotic relationship between two organisms of different species in which one of them is a predator that captures and feeds on the other (prey). 

example of predation

cat and mouse, fox and bandicoot

parasitism

A symbiotic relationship between species, where one organism (parasite), lives on or inside the host organism, causing it some harm, draining it of its resources. 

e.g. of parasitism

ticks and deers, ticks and humans

commensalism

A symbiotic relationship in which one organism benefits from the other organism, but doesn’t harm it in the process. 

e.g. of commensalism

barnacle and a whale, sea anemone and clownfish

mutualism

A symbiotic relationship in which two organisms benefit from each other. 

e.g. mutualism

Honeybee and plant, bacteria and human

ecological niche

• a combination of living and non-living resources that organisms can use to survive

• the role an organism plays in a community

what does ecological niche encompass

both the physical and environmental conditions it requires (like temp and terrain) and interactions with other species (like predation)

Abundance

Relative representation of a species in an ecosystem, measured by the number of individuals per sample.

relative abundance

percent composition of an organism of a particular kind relative to the total number of organisms in the area. 

Distribution

Arrangement of a species within an area influenced by abiotic and biotic factors.

types of dispersion (distribution)

uniform, random, clumped

environment of thylacine

grasslands, wetlands and dry eucalyptus forests.

hypothesis 1 for thylacine

human hunting, european settlers wanted to get ride of them so they could have clear farms, 3500 killed,

may not be true because it is suggested that extinction began long before human hunting

hypothesis 2 for thylacine

competition with dingoes and disease, predicted that dingoes were naturally selected over tassy tigers, because they were more versatile predators, smarter, faster.

which is hypothesis for thylacine is more signficiant

human hunting