Biology Flash Cards

What is reproduction?

The biological process by which organisms create offspring to continue their species (continuity of species)

Why is genetic diversity important?

Makes organisms able to withstand selection pressures and without it they can be vulnerable to selection pressures

What are the two main types of reproduction?

Sexual reproduction and asexual reproduction

What is sexual reproduction?

Requires 2 parents. Fusion of male and female gametes (sex cells). Genetically diverse = able to withstand environmental selection pressures. Takes time and energy to find mate. Slower process with fewer offspring produced. During this process 2 different reactions occur (the acrosome reaction and the cortical reaction)

What is the acrosome reaction?

The acrosome (a cap-like structure in the front of the sperm's head) contains powerful digestive enzymes. When a sperm reaches the egg it encounters the egg's protective layer (zona pellucida). The sperm binds to the egg and releases the enzyme digesting a pathway through the outer layer

What is the cortical reaction?

When a sperm and egg membrane touch the egg cell opens tiny sacs right beneath the surface. These sacs release enzymes that destroy the remaining sperm-binding receptors so sperm can no longer attach and harden the egg's outer layer meaning any sperm trying to tunnel in are completely blocked

What is sexual reproduction in plants?

Involves the fusion of the male (pollen) and female (ovule) gametes

What is the stamen?

The male reproductive organ

What is the carpel?

The female organ

What is pollination?

Occurs when pollen from the anther is transferred to the stigma of the flower (it is NOT a form of fertilization). Allows sexual reproduction to occur (allows the male gamete to reach the female gamete)

What is self-pollination?

Pollination within the same plant

What is cross-pollination?

Pollination between different plants

What are the agents of pollination?

Wind and animals (eg. bees)

What is the method of sexual reproduction in plants?

Pollination transfer of pollen from the anther to the stigma

What are angiosperms?

Flowering plants that reproduce using flowers. Produce seed enclosed within a fruit. After pollination

What are gymnosperms?

Non-flowering plants that reproduce using cones. Seeds are often found exposed on cones

What is a fruit?

The mature ovary of a flowering plant typically containing seeds. It forms after fertilization when the ovary of the flower develops into a protective structure for seeds. Any structure that encases a seed (eg. pod

What is asexual reproduction?

1 Parent. One parent cell produces offspring. Various methods (Budding

What is budding?

Commonly seen in fungi such as yeast and protists (Ex. Hydra). A small outgrowth

What is binary fission?

Commonly seen in bacteria and protists. The process starts when the DNA replicates resulting in 2 copies. The cell then grows and elongates and the two DNA copies move to opposite ends of the cell. The cell membrane divides and a cell wall forms down the middle

What is vegetative propagation?

A type of asexual reproduction in plants where new plants grow from non-reproductive parts of plants (roots

What are the natural methods of vegetative propagation?

Runners (strawberries)

Which organisms can reproduce both sexually and asexually?

Some animals can reproduce both sexually and asexually which allows them to adapt to changing conditions by allowing them to choose to reproduce to keep or diversify their traits depending on environmental conditions. Asexual reproduction occurs in favourable conditions for fast growth. In stressful or changing environments

What are spores?

Tiny reproductive cells produced by fungi that disperse and grow into new fungi (Ex. rhizopus

What is a sporangium?

During asexual reproduction

What is the process of asexual spore formation?

At the tip of the hyphae a sporangium develops. Identical spores are produced inside the sporangium (by mitosis). The sporangium bursts open

What is sexual spore formation?

In sexual reproduction

What is the process of sexual spore formation?

Two different hyphae grew towards each other. The tips of the hyphae fuse together and then the nuclei fuse together

What are gametes?

Sex cells (eg. egg

What are somatic cells?

Body cells (eg. nerve

What is fertilisation?

The process where a male and female gamete (sperm and egg) fuse to form a zygote which then develops into offspring. The male parent contributes the sperm cell

What are the two types of fertilisation?

Internal fertilisation and external fertilisation

What is internal fertilisation?

Occurs inside the female's body. Male gametes are internally transferred into the female's reproductive tract (through a tube in the penis). Will occur only if a mature egg is released (from the ovary) and a swimming sperm can reach it. The haploid (1n) number of chromosomes from the sperm pairs with the haploid number of the ova and forms a zygote. This division and growth continues through mitosis. Common in mammals like elephants and kangaroos

What are the advantages of internal fertilisation?

Higher chance of fertilisation (sperm and eggs protected within). Embryo is protected from predators and harsh environment conditions. Better chance of fertilisation since the gametes are in close proximity. Can take place on land

What are the disadvantages of internal fertilisation?

Fewer offspring produced overall. Requires more time and energy for mating and parental care. Can spread disease through physical and sexual contact (in animals)

What is external fertilisation?

Occurs when eggs and sperm are released into the external environment

What are the advantages of external fertilisation?

Large number of offspring produced at once. No need for complex reproductive organs or mating. Energy and time efficient

What are the disadvantages of external fertilisation?

Lower chance of fertilisation (many gametes may never meet). Egg and sperm are easily eaten or destroyed by the environment/predators. Embryos unprotected = very few survive to adulthood. Cannot take place on land - requires a wet environment

What do the reproductive structures of a female mammal do?

Create a protective

What are the three types of mammals?

Placental

What features do all mammals have in common?

Uterus

What are placental mammals?

Give birth to live young that have developed inside the mother's uterus. Nourish their unborn offspring via placenta that attaches to the walls of the uterus. Examples are dogs

What are marsupials?

Give birth to relatively undeveloped young

What are monotremes?

Lay eggs rather than giving live birth. Eggs are incubated by the mother. Once hatched the young are nourished by milk which the young suckle. Examples are the platypus and echidna

What do the ovaries do?

Produce eggs (ovum) and hormones like estrogen and progesterone

What do the fallopian tubes do?

Transport eggs from the ovaries to the uterus

What is the uterus?

The hollow

What is the endometrium?

The inner lining of the uterus that thickens in preparation for implantation

What does the cervix do?

Controls the entry and exit between the uterus and vagina

What does the vagina do?

Serves as the site for sperm deposition and the birth canal during delivery

What are hormones?

Chemical messengers produced by glands and are essential for regulating various bodily functions

What is ovulation?

The release of a mature egg (ovum) from a follicle in the ovary. It usually occurs around day 14 of a 28 day menstrual cycle. Hormones trigger the release of the egg. The mature follicle bursts

What is the menstrual cycle?

Process that prepares the female body for pregnancy

What is the corpus luteum?

What the empty follicle left behind in the ovary changes into after the egg is released during ovulation

What does follicle stimulating hormone (FSH) do?

Stimulates the development of the follicle in the ovary

What does estrogen do in ovulation?

Produced by the maturing follicle and reaches high levels

What does luteinising hormone (LH) do?

Surges mid-cycle

What is fertilisation in mammals?

Occurs in the fallopian tube. Sperm are ejaculated and immediately begin swimming to the egg

What is implantation in mammals?

Occurs when a fertilised egg (now a blastocyst) attaches to the thickened lining of the uterus (endometrium). This process happens after fertilisation

What does human chorionic gonadotropin (hCG) do?

Maintains the corpus luteum

What does progesterone do in implantation?

Makes the endometrium thick and nutrient rich

What does estrogen do in implantation?

Also supports the growth and thickening of the endometrium

What is pregnancy in mammals?

Begins with successful implantation and is divided into 3 trimesters. During the first trimester

What does progesterone do in pregnancy?

Maintains the lining of the uterus throughout pregnancy and prevents uterus contractions

What does estrogen do in pregnancy?

Promotes the development of fetal organs and stimulates blood flow in the placenta for oxygen and nutrient delivery

What does oxytocin do?

Released during labor to stimulate uterus contractions and assist with delivery and post-birth bonding

What does terrestrial mean?

Land-based

What does desiccation mean?

Drying out

What is airborne transmission?

The process by which pathogens are spread from an infected host to a new host through the air

What is the process of airborne transmission?

An infected host coughs

What does "identify" mean?

Recognise and name it

What does "describe" mean?

Give the characteristics and features

What does "explain" mean?

Relate cause and effect and give the why

What does "compare" mean?

Similarities and differences

What does "contrast" mean?

Show differences

What does "analyse" mean?

Identify the components and the relationships between them

What does "evaluate" mean?

Make a judgement based on criteria

What does "assess" mean?

Make a judgement of value

What does "discuss" mean?

Give points for and/or against

What does "outline" mean?

Indicate the main features of (general terms)

What does "addon" mean?

Using an example/show by example etc: Integrate an example into your response